[PATCH] Add error hints for invalid COPY options

From bb3ece5bb89b1aa265c77a17735d4a206184dabf Mon Sep 17 00:00:00 2001
From: Shinya Sugamoto <sugamoto@me.com>
Date: Sat, 22 Nov 2025 22:03:21 +0900
Subject: [PATCH] Refactor COPY option handling with table-driven approach

Refactor ProcessCopyOptions() to use a table-driven approach for option
handling.  This provides a single source of truth for valid COPY options
- when adding a new option, simply add an entry to the copy_options[]
table and implement its processor function.

Also add error hints for invalid COPY options using ClosestMatch to
suggest similar valid option names, and list all valid values for
options with few choices (format, on_error, log_verbosity).
---
 contrib/file_fdw/expected/file_fdw.out |   3 +
 src/backend/commands/copy.c            | 448 ++++++++++++++++---------
 src/test/regress/expected/copy2.out    |  27 ++
 src/test/regress/sql/copy2.sql         |   7 +
 4 files changed, 323 insertions(+), 162 deletions(-)

diff --git a/contrib/file_fdw/expected/file_fdw.out b/contrib/file_fdw/expected/file_fdw.out
index 5121e27dce5..bf953c62a49 100644
--- a/contrib/file_fdw/expected/file_fdw.out
+++ b/contrib/file_fdw/expected/file_fdw.out
@@ -54,6 +54,7 @@ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS ("a=b" 'true');  -- ERROR
 ERROR:  invalid option name "a=b": must not contain "="
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'xml');  -- ERROR
 ERROR:  COPY format "xml" not recognized
+HINT:  Valid formats are "binary", "csv", and "text".
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'text', quote ':');          -- ERROR
 ERROR:  COPY QUOTE requires CSV mode
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'text', escape ':');         -- ERROR
@@ -96,10 +97,12 @@ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'csv', null '
 ERROR:  COPY null representation cannot use newline or carriage return
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (on_error 'unsupported');       -- ERROR
 ERROR:  COPY ON_ERROR "unsupported" not recognized
+HINT:  Valid values are "ignore" and "stop".
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'binary', on_error 'ignore');       -- ERROR
 ERROR:  only ON_ERROR STOP is allowed in BINARY mode
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (log_verbosity 'unsupported');       -- ERROR
 ERROR:  COPY LOG_VERBOSITY "unsupported" not recognized
+HINT:  Valid values are "default", "silent", and "verbose".
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (reject_limit '1');       -- ERROR
 ERROR:  COPY REJECT_LIMIT requires ON_ERROR to be set to IGNORE
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (on_error 'ignore', reject_limit '0');       -- ERROR
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 28e878c3688..b5ffb3c1062 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -38,6 +38,7 @@
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
 #include "utils/rls.h"
+#include "utils/varlena.h"
 
 /*
  *	 DoCopy executes the SQL COPY statement
@@ -467,6 +468,7 @@ defGetCopyOnErrorChoice(DefElem *def, ParseState *pstate, bool is_from)
 			(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 	/*- translator: first %s is the name of a COPY option, e.g. ON_ERROR */
 			 errmsg("COPY %s \"%s\" not recognized", "ON_ERROR", sval),
+			 errhint("Valid values are \"%s\" and \"%s\".", "ignore", "stop"),
 			 parser_errposition(pstate, def->location)));
 	return COPY_ON_ERROR_STOP;	/* keep compiler quiet */
 }
@@ -525,10 +527,259 @@ defGetCopyLogVerbosityChoice(DefElem *def, ParseState *pstate)
 			(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 	/*- translator: first %s is the name of a COPY option, e.g. ON_ERROR */
 			 errmsg("COPY %s \"%s\" not recognized", "LOG_VERBOSITY", sval),
+			 errhint("Valid values are \"%s\", \"%s\", and \"%s\".", "default", "silent", "verbose"),
 			 parser_errposition(pstate, def->location)));
 	return COPY_LOG_VERBOSITY_DEFAULT;	/* keep compiler quiet */
 }
 
+/*
+ * Context structure for COPY option processing.
+ */
+typedef struct CopyOptionContext
+{
+	ParseState *pstate;
+	CopyFormatOptions *opts_out;
+	bool		is_from;
+	bool		format_specified;
+	bool		freeze_specified;
+	bool		header_specified;
+	bool		on_error_specified;
+	bool		log_verbosity_specified;
+	bool		reject_limit_specified;
+} CopyOptionContext;
+
+/* Individual option processors */
+
+static void
+copy_opt_format(CopyOptionContext *ctx, DefElem *defel)
+{
+	char	   *fmt = defGetString(defel);
+
+	if (ctx->format_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->format_specified = true;
+
+	if (strcmp(fmt, "text") == 0)
+		 /* default format */ ;
+	else if (strcmp(fmt, "csv") == 0)
+		ctx->opts_out->csv_mode = true;
+	else if (strcmp(fmt, "binary") == 0)
+		ctx->opts_out->binary = true;
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("COPY format \"%s\" not recognized", fmt),
+				 errhint("Valid formats are \"%s\", \"%s\", and \"%s\".",
+						 "binary", "csv", "text"),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
+
+static void
+copy_opt_freeze(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->freeze_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->freeze_specified = true;
+	ctx->opts_out->freeze = defGetBoolean(defel);
+}
+
+static void
+copy_opt_delimiter(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->delim)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->delim = defGetString(defel);
+}
+
+static void
+copy_opt_null(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->null_print)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->null_print = defGetString(defel);
+}
+
+static void
+copy_opt_default(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->default_print)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->default_print = defGetString(defel);
+}
+
+static void
+copy_opt_header(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->header_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->header_specified = true;
+	ctx->opts_out->header_line = defGetCopyHeaderOption(defel, ctx->is_from);
+}
+
+static void
+copy_opt_quote(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->quote)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->quote = defGetString(defel);
+}
+
+static void
+copy_opt_escape(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->escape)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->escape = defGetString(defel);
+}
+
+static void
+copy_opt_force_quote(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->force_quote || ctx->opts_out->force_quote_all)
+		errorConflictingDefElem(defel, ctx->pstate);
+	if (defel->arg && IsA(defel->arg, A_Star))
+		ctx->opts_out->force_quote_all = true;
+	else if (defel->arg && IsA(defel->arg, List))
+		ctx->opts_out->force_quote = castNode(List, defel->arg);
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("argument to option \"%s\" must be a list of column names",
+						defel->defname),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
+
+static void
+copy_opt_force_not_null(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->force_notnull || ctx->opts_out->force_notnull_all)
+		errorConflictingDefElem(defel, ctx->pstate);
+	if (defel->arg && IsA(defel->arg, A_Star))
+		ctx->opts_out->force_notnull_all = true;
+	else if (defel->arg && IsA(defel->arg, List))
+		ctx->opts_out->force_notnull = castNode(List, defel->arg);
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("argument to option \"%s\" must be a list of column names",
+						defel->defname),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
+
+static void
+copy_opt_force_null(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->force_null || ctx->opts_out->force_null_all)
+		errorConflictingDefElem(defel, ctx->pstate);
+	if (defel->arg && IsA(defel->arg, A_Star))
+		ctx->opts_out->force_null_all = true;
+	else if (defel->arg && IsA(defel->arg, List))
+		ctx->opts_out->force_null = castNode(List, defel->arg);
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("argument to option \"%s\" must be a list of column names",
+						defel->defname),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
+
+static void
+copy_opt_convert_selectively(CopyOptionContext *ctx, DefElem *defel)
+{
+	/*
+	 * Undocumented, not-accessible-from-SQL option: convert only the
+	 * named columns to binary form, storing the rest as NULLs. It's
+	 * allowed for the column list to be NIL.
+	 */
+	if (ctx->opts_out->convert_selectively)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->convert_selectively = true;
+	if (defel->arg == NULL || IsA(defel->arg, List))
+		ctx->opts_out->convert_select = castNode(List, defel->arg);
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("argument to option \"%s\" must be a list of column names",
+						defel->defname),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
+
+static void
+copy_opt_encoding(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->file_encoding >= 0)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->file_encoding = pg_char_to_encoding(defGetString(defel));
+	if (ctx->opts_out->file_encoding < 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("argument to option \"%s\" must be a valid encoding name",
+						defel->defname),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
+
+static void
+copy_opt_on_error(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->on_error_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->on_error_specified = true;
+	ctx->opts_out->on_error = defGetCopyOnErrorChoice(defel, ctx->pstate,
+													  ctx->is_from);
+}
+
+static void
+copy_opt_log_verbosity(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->log_verbosity_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->log_verbosity_specified = true;
+	ctx->opts_out->log_verbosity = defGetCopyLogVerbosityChoice(defel,
+																ctx->pstate);
+}
+
+static void
+copy_opt_reject_limit(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->reject_limit_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->reject_limit_specified = true;
+	ctx->opts_out->reject_limit = defGetCopyRejectLimitOption(defel);
+}
+
+/*
+ * Table of all valid COPY options.
+ *
+ * This is the single source of truth for valid COPY options.  When adding a
+ * new option, add an entry here and implement its processor function above.
+ */
+static const struct
+{
+	const char *name;
+	void		(*processor) (CopyOptionContext *ctx, DefElem *defel);
+	bool		suggest_in_hints;
+}			copy_options[] =
+
+{
+	{"default", copy_opt_default, true},
+	{"delimiter", copy_opt_delimiter, true},
+	{"encoding", copy_opt_encoding, true},
+	{"escape", copy_opt_escape, true},
+	{"force_not_null", copy_opt_force_not_null, true},
+	{"force_null", copy_opt_force_null, true},
+	{"force_quote", copy_opt_force_quote, true},
+	{"format", copy_opt_format, true},
+	{"freeze", copy_opt_freeze, true},
+	{"header", copy_opt_header, true},
+	{"log_verbosity", copy_opt_log_verbosity, true},
+	{"null", copy_opt_null, true},
+	{"on_error", copy_opt_on_error, true},
+	{"quote", copy_opt_quote, true},
+	{"reject_limit", copy_opt_reject_limit, true},
+	{"convert_selectively", copy_opt_convert_selectively, false},
+	{NULL, NULL, false}
+};
+
 /*
  * Process the statement option list for COPY.
  *
@@ -551,12 +802,7 @@ ProcessCopyOptions(ParseState *pstate,
 				   bool is_from,
 				   List *options)
 {
-	bool		format_specified = false;
-	bool		freeze_specified = false;
-	bool		header_specified = false;
-	bool		on_error_specified = false;
-	bool		log_verbosity_specified = false;
-	bool		reject_limit_specified = false;
+	CopyOptionContext ctx;
 	ListCell   *option;
 
 	/* Support external use for option sanity checking */
@@ -565,177 +811,55 @@ ProcessCopyOptions(ParseState *pstate,
 
 	opts_out->file_encoding = -1;
 
+	/* Initialize option processing context */
+	memset(&ctx, 0, sizeof(ctx));
+	ctx.pstate = pstate;
+	ctx.opts_out = opts_out;
+	ctx.is_from = is_from;
+
 	/* Extract options from the statement node tree */
 	foreach(option, options)
 	{
 		DefElem    *defel = lfirst_node(DefElem, option);
+		bool		found = false;
 
-		if (strcmp(defel->defname, "format") == 0)
-		{
-			char	   *fmt = defGetString(defel);
-
-			if (format_specified)
-				errorConflictingDefElem(defel, pstate);
-			format_specified = true;
-			if (strcmp(fmt, "text") == 0)
-				 /* default format */ ;
-			else if (strcmp(fmt, "csv") == 0)
-				opts_out->csv_mode = true;
-			else if (strcmp(fmt, "binary") == 0)
-				opts_out->binary = true;
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("COPY format \"%s\" not recognized", fmt),
-						 parser_errposition(pstate, defel->location)));
-		}
-		else if (strcmp(defel->defname, "freeze") == 0)
-		{
-			if (freeze_specified)
-				errorConflictingDefElem(defel, pstate);
-			freeze_specified = true;
-			opts_out->freeze = defGetBoolean(defel);
-		}
-		else if (strcmp(defel->defname, "delimiter") == 0)
-		{
-			if (opts_out->delim)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->delim = defGetString(defel);
-		}
-		else if (strcmp(defel->defname, "null") == 0)
-		{
-			if (opts_out->null_print)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->null_print = defGetString(defel);
-		}
-		else if (strcmp(defel->defname, "default") == 0)
-		{
-			if (opts_out->default_print)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->default_print = defGetString(defel);
-		}
-		else if (strcmp(defel->defname, "header") == 0)
-		{
-			if (header_specified)
-				errorConflictingDefElem(defel, pstate);
-			header_specified = true;
-			opts_out->header_line = defGetCopyHeaderOption(defel, is_from);
-		}
-		else if (strcmp(defel->defname, "quote") == 0)
-		{
-			if (opts_out->quote)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->quote = defGetString(defel);
-		}
-		else if (strcmp(defel->defname, "escape") == 0)
-		{
-			if (opts_out->escape)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->escape = defGetString(defel);
-		}
-		else if (strcmp(defel->defname, "force_quote") == 0)
+		/* Look up the option in copy_options table */
+		for (int i = 0; copy_options[i].name != NULL; i++)
 		{
-			if (opts_out->force_quote || opts_out->force_quote_all)
-				errorConflictingDefElem(defel, pstate);
-			if (defel->arg && IsA(defel->arg, A_Star))
-				opts_out->force_quote_all = true;
-			else if (defel->arg && IsA(defel->arg, List))
-				opts_out->force_quote = castNode(List, defel->arg);
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("argument to option \"%s\" must be a list of column names",
-								defel->defname),
-						 parser_errposition(pstate, defel->location)));
-		}
-		else if (strcmp(defel->defname, "force_not_null") == 0)
-		{
-			if (opts_out->force_notnull || opts_out->force_notnull_all)
-				errorConflictingDefElem(defel, pstate);
-			if (defel->arg && IsA(defel->arg, A_Star))
-				opts_out->force_notnull_all = true;
-			else if (defel->arg && IsA(defel->arg, List))
-				opts_out->force_notnull = castNode(List, defel->arg);
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("argument to option \"%s\" must be a list of column names",
-								defel->defname),
-						 parser_errposition(pstate, defel->location)));
-		}
-		else if (strcmp(defel->defname, "force_null") == 0)
-		{
-			if (opts_out->force_null || opts_out->force_null_all)
-				errorConflictingDefElem(defel, pstate);
-			if (defel->arg && IsA(defel->arg, A_Star))
-				opts_out->force_null_all = true;
-			else if (defel->arg && IsA(defel->arg, List))
-				opts_out->force_null = castNode(List, defel->arg);
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("argument to option \"%s\" must be a list of column names",
-								defel->defname),
-						 parser_errposition(pstate, defel->location)));
+			if (strcmp(copy_options[i].name, defel->defname) == 0)
+			{
+				copy_options[i].processor(&ctx, defel);
+				found = true;
+				break;
+			}
 		}
-		else if (strcmp(defel->defname, "convert_selectively") == 0)
+
+		if (!found)
 		{
 			/*
-			 * Undocumented, not-accessible-from-SQL option: convert only the
-			 * named columns to binary form, storing the rest as NULLs. It's
-			 * allowed for the column list to be NIL.
+			 * When an unknown option is specified, complain about it.
+			 * Provide a hint with a valid option that looks similar, if there
+			 * is one.
 			 */
-			if (opts_out->convert_selectively)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->convert_selectively = true;
-			if (defel->arg == NULL || IsA(defel->arg, List))
-				opts_out->convert_select = castNode(List, defel->arg);
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("argument to option \"%s\" must be a list of column names",
-								defel->defname),
-						 parser_errposition(pstate, defel->location)));
-		}
-		else if (strcmp(defel->defname, "encoding") == 0)
-		{
-			if (opts_out->file_encoding >= 0)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->file_encoding = pg_char_to_encoding(defGetString(defel));
-			if (opts_out->file_encoding < 0)
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("argument to option \"%s\" must be a valid encoding name",
-								defel->defname),
-						 parser_errposition(pstate, defel->location)));
-		}
-		else if (strcmp(defel->defname, "on_error") == 0)
-		{
-			if (on_error_specified)
-				errorConflictingDefElem(defel, pstate);
-			on_error_specified = true;
-			opts_out->on_error = defGetCopyOnErrorChoice(defel, pstate, is_from);
-		}
-		else if (strcmp(defel->defname, "log_verbosity") == 0)
-		{
-			if (log_verbosity_specified)
-				errorConflictingDefElem(defel, pstate);
-			log_verbosity_specified = true;
-			opts_out->log_verbosity = defGetCopyLogVerbosityChoice(defel, pstate);
-		}
-		else if (strcmp(defel->defname, "reject_limit") == 0)
-		{
-			if (reject_limit_specified)
-				errorConflictingDefElem(defel, pstate);
-			reject_limit_specified = true;
-			opts_out->reject_limit = defGetCopyRejectLimitOption(defel);
-		}
-		else
+			ClosestMatchState match_state;
+			const char *closest_match;
+
+			initClosestMatch(&match_state, defel->defname, 4);
+			for (int i = 0; copy_options[i].name != NULL; i++)
+			{
+				if (copy_options[i].suggest_in_hints)
+					updateClosestMatch(&match_state, copy_options[i].name);
+			}
+
+			closest_match = getClosestMatch(&match_state);
 			ereport(ERROR,
 					(errcode(ERRCODE_SYNTAX_ERROR),
 					 errmsg("option \"%s\" not recognized",
 							defel->defname),
+					 closest_match ?
+					 errhint("Perhaps you meant \"%s\".", closest_match) : 0,
 					 parser_errposition(pstate, defel->location)));
+		}
 	}
 
 	/*
diff --git a/src/test/regress/expected/copy2.out b/src/test/regress/expected/copy2.out
index f3fdce23459..a4b4e33248f 100644
--- a/src/test/regress/expected/copy2.out
+++ b/src/test/regress/expected/copy2.out
@@ -96,6 +96,7 @@ COPY x from stdin (on_error unsupported);
 ERROR:  COPY ON_ERROR "unsupported" not recognized
 LINE 1: COPY x from stdin (on_error unsupported);
                            ^
+HINT:  Valid values are "ignore" and "stop".
 COPY x from stdin (format TEXT, force_quote(a));
 ERROR:  COPY FORCE_QUOTE requires CSV mode
 COPY x from stdin (format TEXT, force_quote *);
@@ -128,6 +129,7 @@ COPY x from stdin (log_verbosity unsupported);
 ERROR:  COPY LOG_VERBOSITY "unsupported" not recognized
 LINE 1: COPY x from stdin (log_verbosity unsupported);
                            ^
+HINT:  Valid values are "default", "silent", and "verbose".
 COPY x from stdin with (reject_limit 1);
 ERROR:  COPY REJECT_LIMIT requires ON_ERROR to be set to IGNORE
 COPY x from stdin with (on_error ignore, reject_limit 0);
@@ -138,6 +140,31 @@ COPY x from stdin with (header 2.5);
 ERROR:  header requires a Boolean value, a non-negative integer, or the string "match"
 COPY x to stdout with (header 2);
 ERROR:  cannot use multi-line header in COPY TO
+-- test error hints for invalid COPY options
+COPY x from stdin (foramt CSV);  -- error, suggests "format"
+ERROR:  option "foramt" not recognized
+LINE 1: COPY x from stdin (foramt CSV);
+                           ^
+HINT:  Perhaps you meant "format".
+COPY x from stdin (completely_invalid_option 'value');  -- error, no suggestion
+ERROR:  option "completely_invalid_option" not recognized
+LINE 1: COPY x from stdin (completely_invalid_option 'value');
+                           ^
+COPY x from stdin (format cvs);  -- error, lists valid formats
+ERROR:  COPY format "cvs" not recognized
+LINE 1: COPY x from stdin (format cvs);
+                           ^
+HINT:  Valid formats are "binary", "csv", and "text".
+COPY x from stdin (format CSV, on_error ignor);  -- error, lists valid on_error values
+ERROR:  COPY ON_ERROR "ignor" not recognized
+LINE 1: COPY x from stdin (format CSV, on_error ignor);
+                                       ^
+HINT:  Valid values are "ignore" and "stop".
+COPY x from stdin (format CSV, log_verbosity verbos);  -- error, lists valid log_verbosity values
+ERROR:  COPY LOG_VERBOSITY "verbos" not recognized
+LINE 1: COPY x from stdin (format CSV, log_verbosity verbos);
+                                       ^
+HINT:  Valid values are "default", "silent", and "verbose".
 -- too many columns in column list: should fail
 COPY x (a, b, c, d, e, d, c) from stdin;
 ERROR:  column "d" specified more than once
diff --git a/src/test/regress/sql/copy2.sql b/src/test/regress/sql/copy2.sql
index cef45868db5..b8c9d2439ef 100644
--- a/src/test/regress/sql/copy2.sql
+++ b/src/test/regress/sql/copy2.sql
@@ -94,6 +94,13 @@ COPY x from stdin with (header -1);
 COPY x from stdin with (header 2.5);
 COPY x to stdout with (header 2);
 
+-- test error hints for invalid COPY options
+COPY x from stdin (foramt CSV);  -- error, suggests "format"
+COPY x from stdin (completely_invalid_option 'value');  -- error, no suggestion
+COPY x from stdin (format cvs);  -- error, lists valid formats
+COPY x from stdin (format CSV, on_error ignor);  -- error, lists valid on_error values
+COPY x from stdin (format CSV, log_verbosity verbos);  -- error, lists valid log_verbosity values
+
 -- too many columns in column list: should fail
 COPY x (a, b, c, d, e, d, c) from stdin;
 
-- 
2.50.1 (Apple Git-155)

From c923fce80ee0d6cb8bc37f0dd893abc069a01c26 Mon Sep 17 00:00:00 2001
From: Shinya Sugamoto <sugamoto@me.com>
Date: Sat, 22 Nov 2025 22:03:21 +0900
Subject: [PATCH] Refactor COPY option handling and improve error hints
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- Restructure ProcessCopyOptions() so that each option has its own
	processor function. This makes option handling more modular and
	easier to extend.
- Improve error messages by adding hints that show valid values
	when users specify unrecognized option values.
---
 contrib/file_fdw/expected/file_fdw.out |   3 +
 src/backend/commands/copy.c            | 597 ++++++++++++++-----------
 src/test/regress/expected/copy2.out    |  27 ++
 src/test/regress/sql/copy2.sql         |   7 +
 4 files changed, 375 insertions(+), 259 deletions(-)

diff --git a/contrib/file_fdw/expected/file_fdw.out b/contrib/file_fdw/expected/file_fdw.out
index 5121e27dce5..bf953c62a49 100644
--- a/contrib/file_fdw/expected/file_fdw.out
+++ b/contrib/file_fdw/expected/file_fdw.out
@@ -54,6 +54,7 @@ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS ("a=b" 'true');  -- ERROR
 ERROR:  invalid option name "a=b": must not contain "="
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'xml');  -- ERROR
 ERROR:  COPY format "xml" not recognized
+HINT:  Valid formats are "binary", "csv", and "text".
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'text', quote ':');          -- ERROR
 ERROR:  COPY QUOTE requires CSV mode
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'text', escape ':');         -- ERROR
@@ -96,10 +97,12 @@ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'csv', null '
 ERROR:  COPY null representation cannot use newline or carriage return
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (on_error 'unsupported');       -- ERROR
 ERROR:  COPY ON_ERROR "unsupported" not recognized
+HINT:  Valid values are "ignore" and "stop".
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'binary', on_error 'ignore');       -- ERROR
 ERROR:  only ON_ERROR STOP is allowed in BINARY mode
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (log_verbosity 'unsupported');       -- ERROR
 ERROR:  COPY LOG_VERBOSITY "unsupported" not recognized
+HINT:  Valid values are "default", "silent", and "verbose".
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (reject_limit '1');       -- ERROR
 ERROR:  COPY REJECT_LIMIT requires ON_ERROR to be set to IGNORE
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (on_error 'ignore', reject_limit '0');       -- ERROR
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 28e878c3688..804810c2272 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -38,6 +38,7 @@
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
 #include "utils/rls.h"
+#include "utils/varlena.h"
 
 /*
  *	 DoCopy executes the SQL COPY statement
@@ -365,133 +366,328 @@ DoCopy(ParseState *pstate, const CopyStmt *stmt,
 }
 
 /*
- * Extract the CopyFormatOptions.header_line value from a DefElem.
- *
- * Parses the HEADER option for COPY, which can be a boolean, a non-negative
- * integer (number of lines to skip), or the special value "match".
+ * Context structure for COPY option processing.
  */
-static int
-defGetCopyHeaderOption(DefElem *def, bool is_from)
+typedef struct CopyOptionContext
 {
-	/*
-	 * If no parameter value given, assume "true" is meant.
-	 */
-	if (def->arg == NULL)
-		return COPY_HEADER_TRUE;
+	ParseState *pstate;
+	CopyFormatOptions *opts_out;
+	bool		is_from;
+	bool		format_specified;
+	bool		freeze_specified;
+	bool		header_specified;
+	bool		on_error_specified;
+	bool		log_verbosity_specified;
+	bool		reject_limit_specified;
+} CopyOptionContext;
+
+/* Individual option processors */
+
+static void
+processOptionFormat(CopyOptionContext *ctx, DefElem *defel)
+{
+	char	   *fmt = defGetString(defel);
+
+	if (ctx->format_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->format_specified = true;
+
+	if (strcmp(fmt, "text") == 0)
+		 /* default format */ ;
+	else if (strcmp(fmt, "csv") == 0)
+		ctx->opts_out->csv_mode = true;
+	else if (strcmp(fmt, "binary") == 0)
+		ctx->opts_out->binary = true;
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("COPY format \"%s\" not recognized", fmt),
+				 errhint("Valid formats are \"%s\", \"%s\", and \"%s\".",
+						 "binary", "csv", "text"),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
 
-	/*
-	 * Allow 0, 1, "true", "false", "on", "off", a non-negative integer, or
-	 * "match".
-	 */
-	switch (nodeTag(def->arg))
+static void
+processOptionFreeze(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->freeze_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->freeze_specified = true;
+	ctx->opts_out->freeze = defGetBoolean(defel);
+}
+
+static void
+processOptionDelimiter(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->delim)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->delim = defGetString(defel);
+}
+
+static void
+processOptionNull(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->null_print)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->null_print = defGetString(defel);
+}
+
+static void
+processOptionDefault(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->default_print)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->default_print = defGetString(defel);
+}
+
+static void
+processOptionHeader(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->header_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->header_specified = true;
+
+	if (defel->arg == NULL)
+	{
+		ctx->opts_out->header_line = COPY_HEADER_TRUE;
+		return;
+	}
+	switch (nodeTag(defel->arg))
 	{
 		case T_Integer:
 			{
-				int			ival = intVal(def->arg);
+				int			ival = intVal(defel->arg);
 
 				if (ival < 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 							 errmsg("a negative integer value cannot be "
-									"specified for %s", def->defname)));
+									"specified for %s", defel->defname)));
 
-				if (!is_from && ival > 1)
+				if (!ctx->is_from && ival > 1)
 					ereport(ERROR,
 							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 							 errmsg("cannot use multi-line header in COPY TO")));
 
-				return ival;
+				ctx->opts_out->header_line = ival;
+				return;
 			}
-			break;
 		default:
 			{
-				char	   *sval = defGetString(def);
+				char	   *sval = defGetString(defel);
 
-				/*
-				 * The set of strings accepted here should match up with the
-				 * grammar's opt_boolean_or_string production.
-				 */
-				if (pg_strcasecmp(sval, "true") == 0)
-					return COPY_HEADER_TRUE;
-				if (pg_strcasecmp(sval, "false") == 0)
-					return COPY_HEADER_FALSE;
-				if (pg_strcasecmp(sval, "on") == 0)
-					return COPY_HEADER_TRUE;
-				if (pg_strcasecmp(sval, "off") == 0)
-					return COPY_HEADER_FALSE;
+				if (pg_strcasecmp(sval, "true") == 0 ||
+					pg_strcasecmp(sval, "on") == 0)
+				{
+					ctx->opts_out->header_line = COPY_HEADER_TRUE;
+					return;
+				}
+				if (pg_strcasecmp(sval, "false") == 0 ||
+					pg_strcasecmp(sval, "off") == 0)
+				{
+					ctx->opts_out->header_line = COPY_HEADER_FALSE;
+					return;
+				}
 				if (pg_strcasecmp(sval, "match") == 0)
 				{
-					if (!is_from)
+					if (!ctx->is_from)
 						ereport(ERROR,
 								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 								 errmsg("cannot use \"%s\" with HEADER in COPY TO",
 										sval)));
-					return COPY_HEADER_MATCH;
+					ctx->opts_out->header_line = COPY_HEADER_MATCH;
+					return;
 				}
 			}
 			break;
 	}
+
 	ereport(ERROR,
 			(errcode(ERRCODE_SYNTAX_ERROR),
 			 errmsg("%s requires a Boolean value, a non-negative integer, "
 					"or the string \"match\"",
-					def->defname)));
-	return COPY_HEADER_FALSE;	/* keep compiler quiet */
+					defel->defname)));
 }
 
-/*
- * Extract a CopyOnErrorChoice value from a DefElem.
- */
-static CopyOnErrorChoice
-defGetCopyOnErrorChoice(DefElem *def, ParseState *pstate, bool is_from)
+static void
+processOptionQuote(CopyOptionContext *ctx, DefElem *defel)
 {
-	char	   *sval = defGetString(def);
+	if (ctx->opts_out->quote)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->quote = defGetString(defel);
+}
 
-	if (!is_from)
+static void
+processOptionEscape(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->escape)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->escape = defGetString(defel);
+}
+
+static void
+processOptionForceQuote(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->force_quote || ctx->opts_out->force_quote_all)
+		errorConflictingDefElem(defel, ctx->pstate);
+
+	if (defel->arg && IsA(defel->arg, A_Star))
+		ctx->opts_out->force_quote_all = true;
+	else if (defel->arg && IsA(defel->arg, List))
+		ctx->opts_out->force_quote = castNode(List, defel->arg);
+	else
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-		/*- translator: first %s is the name of a COPY option, e.g. ON_ERROR,
-		 second %s is a COPY with direction, e.g. COPY TO */
-				 errmsg("COPY %s cannot be used with %s", "ON_ERROR", "COPY TO"),
-				 parser_errposition(pstate, def->location)));
+				 errmsg("argument to option \"%s\" must be a list of column names",
+						defel->defname),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
+
+static void
+processOptionForceNotNull(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->force_notnull || ctx->opts_out->force_notnull_all)
+		errorConflictingDefElem(defel, ctx->pstate);
+
+	if (defel->arg && IsA(defel->arg, A_Star))
+		ctx->opts_out->force_notnull_all = true;
+	else if (defel->arg && IsA(defel->arg, List))
+		ctx->opts_out->force_notnull = castNode(List, defel->arg);
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("argument to option \"%s\" must be a list of column names",
+						defel->defname),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
+
+static void
+processOptionForceNull(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->force_null || ctx->opts_out->force_null_all)
+		errorConflictingDefElem(defel, ctx->pstate);
+
+	if (defel->arg && IsA(defel->arg, A_Star))
+		ctx->opts_out->force_null_all = true;
+	else if (defel->arg && IsA(defel->arg, List))
+		ctx->opts_out->force_null = castNode(List, defel->arg);
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("argument to option \"%s\" must be a list of column names",
+						defel->defname),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
 
+static void
+processOptionConvertSelectively(CopyOptionContext *ctx, DefElem *defel)
+{
 	/*
-	 * Allow "stop", or "ignore" values.
+	 * Undocumented, not-accessible-from-SQL option: convert only the
+	 * named columns to binary form, storing the rest as NULLs. It's
+	 * allowed for the column list to be NIL.
 	 */
+	if (ctx->opts_out->convert_selectively)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->opts_out->convert_selectively = true;
+
+	if (defel->arg == NULL || IsA(defel->arg, List))
+		ctx->opts_out->convert_select = castNode(List, defel->arg);
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("argument to option \"%s\" must be a list of column names",
+						defel->defname),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
+
+static void
+processOptionEncoding(CopyOptionContext *ctx, DefElem *defel)
+{
+	if (ctx->opts_out->file_encoding >= 0)
+		errorConflictingDefElem(defel, ctx->pstate);
+
+	ctx->opts_out->file_encoding = pg_char_to_encoding(defGetString(defel));
+	if (ctx->opts_out->file_encoding < 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("argument to option \"%s\" must be a valid encoding name",
+						defel->defname),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
+
+/* Process ON_ERROR option: "stop" or "ignore" */
+static void
+processOptionOnError(CopyOptionContext *ctx, DefElem *defel)
+{
+	char	   *sval;
+
+	if (ctx->on_error_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->on_error_specified = true;
+
+	if (!ctx->is_from)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("COPY %s cannot be used with %s", "ON_ERROR", "COPY TO"),
+				 parser_errposition(ctx->pstate, defel->location)));
+
+	sval = defGetString(defel);
 	if (pg_strcasecmp(sval, "stop") == 0)
-		return COPY_ON_ERROR_STOP;
-	if (pg_strcasecmp(sval, "ignore") == 0)
-		return COPY_ON_ERROR_IGNORE;
+		ctx->opts_out->on_error = COPY_ON_ERROR_STOP;
+	else if (pg_strcasecmp(sval, "ignore") == 0)
+		ctx->opts_out->on_error = COPY_ON_ERROR_IGNORE;
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("COPY %s \"%s\" not recognized", "ON_ERROR", sval),
+				 errhint("Valid values are \"%s\" and \"%s\".", "ignore", "stop"),
+				 parser_errposition(ctx->pstate, defel->location)));
+}
 
-	ereport(ERROR,
-			(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-	/*- translator: first %s is the name of a COPY option, e.g. ON_ERROR */
-			 errmsg("COPY %s \"%s\" not recognized", "ON_ERROR", sval),
-			 parser_errposition(pstate, def->location)));
-	return COPY_ON_ERROR_STOP;	/* keep compiler quiet */
+static void
+processOptionLogVerbosity(CopyOptionContext *ctx, DefElem *defel)
+{
+	char	   *sval;
+
+	if (ctx->log_verbosity_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->log_verbosity_specified = true;
+
+	sval = defGetString(defel);
+	if (pg_strcasecmp(sval, "silent") == 0)
+		ctx->opts_out->log_verbosity = COPY_LOG_VERBOSITY_SILENT;
+	else if (pg_strcasecmp(sval, "default") == 0)
+		ctx->opts_out->log_verbosity = COPY_LOG_VERBOSITY_DEFAULT;
+	else if (pg_strcasecmp(sval, "verbose") == 0)
+		ctx->opts_out->log_verbosity = COPY_LOG_VERBOSITY_VERBOSE;
+	else
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("COPY %s \"%s\" not recognized", "LOG_VERBOSITY", sval),
+				 errhint("Valid values are \"%s\", \"%s\", and \"%s\".",
+						 "default", "silent", "verbose"),
+				 parser_errposition(ctx->pstate, defel->location)));
 }
 
-/*
- * Extract REJECT_LIMIT value from a DefElem.
- *
- * REJECT_LIMIT can be specified in two ways: as an int64 for the COPY command
- * option or as a single-quoted string for the foreign table option using
- * file_fdw. Therefore this function needs to handle both formats.
- */
-static int64
-defGetCopyRejectLimitOption(DefElem *def)
+static void
+processOptionRejectLimit(CopyOptionContext *ctx, DefElem *defel)
 {
 	int64		reject_limit;
 
-	if (def->arg == NULL)
+	if (ctx->reject_limit_specified)
+		errorConflictingDefElem(defel, ctx->pstate);
+	ctx->reject_limit_specified = true;
+
+	if (defel->arg == NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_SYNTAX_ERROR),
-				 errmsg("%s requires a numeric value",
-						def->defname)));
-	else if (nodeTag(def->arg) == T_String)
-		reject_limit = pg_strtoint64(strVal(def->arg));
+				 errmsg("%s requires a numeric value", defel->defname)));
+
+	if (nodeTag(defel->arg) == T_String)
+		reject_limit = pg_strtoint64(strVal(defel->arg));
 	else
-		reject_limit = defGetInt64(def);
+		reject_limit = defGetInt64(defel);
 
 	if (reject_limit <= 0)
 		ereport(ERROR,
@@ -499,35 +695,45 @@ defGetCopyRejectLimitOption(DefElem *def)
 				 errmsg("REJECT_LIMIT (%" PRId64 ") must be greater than zero",
 						reject_limit)));
 
-	return reject_limit;
+	ctx->opts_out->reject_limit = reject_limit;
 }
 
 /*
- * Extract a CopyLogVerbosityChoice value from a DefElem.
+ * Definition of a COPY option.
  */
-static CopyLogVerbosityChoice
-defGetCopyLogVerbosityChoice(DefElem *def, ParseState *pstate)
+typedef struct CopyOptionDef
 {
-	char	   *sval;
+	const char *name;
+	void		(*processor) (CopyOptionContext *ctx, DefElem *defel);
+	bool		suggest_in_hints;
+} CopyOptionDef;
 
-	/*
-	 * Allow "silent", "default", or "verbose" values.
-	 */
-	sval = defGetString(def);
-	if (pg_strcasecmp(sval, "silent") == 0)
-		return COPY_LOG_VERBOSITY_SILENT;
-	if (pg_strcasecmp(sval, "default") == 0)
-		return COPY_LOG_VERBOSITY_DEFAULT;
-	if (pg_strcasecmp(sval, "verbose") == 0)
-		return COPY_LOG_VERBOSITY_VERBOSE;
-
-	ereport(ERROR,
-			(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-	/*- translator: first %s is the name of a COPY option, e.g. ON_ERROR */
-			 errmsg("COPY %s \"%s\" not recognized", "LOG_VERBOSITY", sval),
-			 parser_errposition(pstate, def->location)));
-	return COPY_LOG_VERBOSITY_DEFAULT;	/* keep compiler quiet */
-}
+/*
+ * Table of all valid COPY options.
+ *
+ * This is the single source of truth for valid COPY options.  When adding a
+ * new option, add an entry here and implement its processor function above.
+ */
+static const CopyOptionDef copy_options[] =
+{
+	{"default", processOptionDefault, true},
+	{"delimiter", processOptionDelimiter, true},
+	{"encoding", processOptionEncoding, true},
+	{"escape", processOptionEscape, true},
+	{"force_not_null", processOptionForceNotNull, true},
+	{"force_null", processOptionForceNull, true},
+	{"force_quote", processOptionForceQuote, true},
+	{"format", processOptionFormat, true},
+	{"freeze", processOptionFreeze, true},
+	{"header", processOptionHeader, true},
+	{"log_verbosity", processOptionLogVerbosity, true},
+	{"null", processOptionNull, true},
+	{"on_error", processOptionOnError, true},
+	{"quote", processOptionQuote, true},
+	{"reject_limit", processOptionRejectLimit, true},
+	{"convert_selectively", processOptionConvertSelectively, false},
+	{NULL, NULL, false}
+};
 
 /*
  * Process the statement option list for COPY.
@@ -551,12 +757,7 @@ ProcessCopyOptions(ParseState *pstate,
 				   bool is_from,
 				   List *options)
 {
-	bool		format_specified = false;
-	bool		freeze_specified = false;
-	bool		header_specified = false;
-	bool		on_error_specified = false;
-	bool		log_verbosity_specified = false;
-	bool		reject_limit_specified = false;
+	CopyOptionContext ctx;
 	ListCell   *option;
 
 	/* Support external use for option sanity checking */
@@ -565,177 +766,55 @@ ProcessCopyOptions(ParseState *pstate,
 
 	opts_out->file_encoding = -1;
 
+	/* Initialize option processing context */
+	memset(&ctx, 0, sizeof(ctx));
+	ctx.pstate = pstate;
+	ctx.opts_out = opts_out;
+	ctx.is_from = is_from;
+
 	/* Extract options from the statement node tree */
 	foreach(option, options)
 	{
 		DefElem    *defel = lfirst_node(DefElem, option);
+		bool		found = false;
 
-		if (strcmp(defel->defname, "format") == 0)
-		{
-			char	   *fmt = defGetString(defel);
-
-			if (format_specified)
-				errorConflictingDefElem(defel, pstate);
-			format_specified = true;
-			if (strcmp(fmt, "text") == 0)
-				 /* default format */ ;
-			else if (strcmp(fmt, "csv") == 0)
-				opts_out->csv_mode = true;
-			else if (strcmp(fmt, "binary") == 0)
-				opts_out->binary = true;
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("COPY format \"%s\" not recognized", fmt),
-						 parser_errposition(pstate, defel->location)));
-		}
-		else if (strcmp(defel->defname, "freeze") == 0)
-		{
-			if (freeze_specified)
-				errorConflictingDefElem(defel, pstate);
-			freeze_specified = true;
-			opts_out->freeze = defGetBoolean(defel);
-		}
-		else if (strcmp(defel->defname, "delimiter") == 0)
-		{
-			if (opts_out->delim)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->delim = defGetString(defel);
-		}
-		else if (strcmp(defel->defname, "null") == 0)
-		{
-			if (opts_out->null_print)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->null_print = defGetString(defel);
-		}
-		else if (strcmp(defel->defname, "default") == 0)
-		{
-			if (opts_out->default_print)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->default_print = defGetString(defel);
-		}
-		else if (strcmp(defel->defname, "header") == 0)
-		{
-			if (header_specified)
-				errorConflictingDefElem(defel, pstate);
-			header_specified = true;
-			opts_out->header_line = defGetCopyHeaderOption(defel, is_from);
-		}
-		else if (strcmp(defel->defname, "quote") == 0)
-		{
-			if (opts_out->quote)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->quote = defGetString(defel);
-		}
-		else if (strcmp(defel->defname, "escape") == 0)
-		{
-			if (opts_out->escape)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->escape = defGetString(defel);
-		}
-		else if (strcmp(defel->defname, "force_quote") == 0)
-		{
-			if (opts_out->force_quote || opts_out->force_quote_all)
-				errorConflictingDefElem(defel, pstate);
-			if (defel->arg && IsA(defel->arg, A_Star))
-				opts_out->force_quote_all = true;
-			else if (defel->arg && IsA(defel->arg, List))
-				opts_out->force_quote = castNode(List, defel->arg);
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("argument to option \"%s\" must be a list of column names",
-								defel->defname),
-						 parser_errposition(pstate, defel->location)));
-		}
-		else if (strcmp(defel->defname, "force_not_null") == 0)
-		{
-			if (opts_out->force_notnull || opts_out->force_notnull_all)
-				errorConflictingDefElem(defel, pstate);
-			if (defel->arg && IsA(defel->arg, A_Star))
-				opts_out->force_notnull_all = true;
-			else if (defel->arg && IsA(defel->arg, List))
-				opts_out->force_notnull = castNode(List, defel->arg);
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("argument to option \"%s\" must be a list of column names",
-								defel->defname),
-						 parser_errposition(pstate, defel->location)));
-		}
-		else if (strcmp(defel->defname, "force_null") == 0)
+		/* Look up the option in copy_options table */
+		for (int i = 0; copy_options[i].name != NULL; i++)
 		{
-			if (opts_out->force_null || opts_out->force_null_all)
-				errorConflictingDefElem(defel, pstate);
-			if (defel->arg && IsA(defel->arg, A_Star))
-				opts_out->force_null_all = true;
-			else if (defel->arg && IsA(defel->arg, List))
-				opts_out->force_null = castNode(List, defel->arg);
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("argument to option \"%s\" must be a list of column names",
-								defel->defname),
-						 parser_errposition(pstate, defel->location)));
+			if (strcmp(copy_options[i].name, defel->defname) == 0)
+			{
+				copy_options[i].processor(&ctx, defel);
+				found = true;
+				break;
+			}
 		}
-		else if (strcmp(defel->defname, "convert_selectively") == 0)
+
+		if (!found)
 		{
 			/*
-			 * Undocumented, not-accessible-from-SQL option: convert only the
-			 * named columns to binary form, storing the rest as NULLs. It's
-			 * allowed for the column list to be NIL.
+			 * When an unknown option is specified, complain about it.
+			 * Provide a hint with a valid option that looks similar, if there
+			 * is one.
 			 */
-			if (opts_out->convert_selectively)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->convert_selectively = true;
-			if (defel->arg == NULL || IsA(defel->arg, List))
-				opts_out->convert_select = castNode(List, defel->arg);
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("argument to option \"%s\" must be a list of column names",
-								defel->defname),
-						 parser_errposition(pstate, defel->location)));
-		}
-		else if (strcmp(defel->defname, "encoding") == 0)
-		{
-			if (opts_out->file_encoding >= 0)
-				errorConflictingDefElem(defel, pstate);
-			opts_out->file_encoding = pg_char_to_encoding(defGetString(defel));
-			if (opts_out->file_encoding < 0)
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("argument to option \"%s\" must be a valid encoding name",
-								defel->defname),
-						 parser_errposition(pstate, defel->location)));
-		}
-		else if (strcmp(defel->defname, "on_error") == 0)
-		{
-			if (on_error_specified)
-				errorConflictingDefElem(defel, pstate);
-			on_error_specified = true;
-			opts_out->on_error = defGetCopyOnErrorChoice(defel, pstate, is_from);
-		}
-		else if (strcmp(defel->defname, "log_verbosity") == 0)
-		{
-			if (log_verbosity_specified)
-				errorConflictingDefElem(defel, pstate);
-			log_verbosity_specified = true;
-			opts_out->log_verbosity = defGetCopyLogVerbosityChoice(defel, pstate);
-		}
-		else if (strcmp(defel->defname, "reject_limit") == 0)
-		{
-			if (reject_limit_specified)
-				errorConflictingDefElem(defel, pstate);
-			reject_limit_specified = true;
-			opts_out->reject_limit = defGetCopyRejectLimitOption(defel);
-		}
-		else
+			ClosestMatchState match_state;
+			const char *closest_match;
+
+			initClosestMatch(&match_state, defel->defname, 4);
+			for (int i = 0; copy_options[i].name != NULL; i++)
+			{
+				if (copy_options[i].suggest_in_hints)
+					updateClosestMatch(&match_state, copy_options[i].name);
+			}
+
+			closest_match = getClosestMatch(&match_state);
 			ereport(ERROR,
 					(errcode(ERRCODE_SYNTAX_ERROR),
 					 errmsg("option \"%s\" not recognized",
 							defel->defname),
+					 closest_match ?
+					 errhint("Perhaps you meant \"%s\".", closest_match) : 0,
 					 parser_errposition(pstate, defel->location)));
+		}
 	}
 
 	/*
diff --git a/src/test/regress/expected/copy2.out b/src/test/regress/expected/copy2.out
index f3fdce23459..a4b4e33248f 100644
--- a/src/test/regress/expected/copy2.out
+++ b/src/test/regress/expected/copy2.out
@@ -96,6 +96,7 @@ COPY x from stdin (on_error unsupported);
 ERROR:  COPY ON_ERROR "unsupported" not recognized
 LINE 1: COPY x from stdin (on_error unsupported);
                            ^
+HINT:  Valid values are "ignore" and "stop".
 COPY x from stdin (format TEXT, force_quote(a));
 ERROR:  COPY FORCE_QUOTE requires CSV mode
 COPY x from stdin (format TEXT, force_quote *);
@@ -128,6 +129,7 @@ COPY x from stdin (log_verbosity unsupported);
 ERROR:  COPY LOG_VERBOSITY "unsupported" not recognized
 LINE 1: COPY x from stdin (log_verbosity unsupported);
                            ^
+HINT:  Valid values are "default", "silent", and "verbose".
 COPY x from stdin with (reject_limit 1);
 ERROR:  COPY REJECT_LIMIT requires ON_ERROR to be set to IGNORE
 COPY x from stdin with (on_error ignore, reject_limit 0);
@@ -138,6 +140,31 @@ COPY x from stdin with (header 2.5);
 ERROR:  header requires a Boolean value, a non-negative integer, or the string "match"
 COPY x to stdout with (header 2);
 ERROR:  cannot use multi-line header in COPY TO
+-- test error hints for invalid COPY options
+COPY x from stdin (foramt CSV);  -- error, suggests "format"
+ERROR:  option "foramt" not recognized
+LINE 1: COPY x from stdin (foramt CSV);
+                           ^
+HINT:  Perhaps you meant "format".
+COPY x from stdin (completely_invalid_option 'value');  -- error, no suggestion
+ERROR:  option "completely_invalid_option" not recognized
+LINE 1: COPY x from stdin (completely_invalid_option 'value');
+                           ^
+COPY x from stdin (format cvs);  -- error, lists valid formats
+ERROR:  COPY format "cvs" not recognized
+LINE 1: COPY x from stdin (format cvs);
+                           ^
+HINT:  Valid formats are "binary", "csv", and "text".
+COPY x from stdin (format CSV, on_error ignor);  -- error, lists valid on_error values
+ERROR:  COPY ON_ERROR "ignor" not recognized
+LINE 1: COPY x from stdin (format CSV, on_error ignor);
+                                       ^
+HINT:  Valid values are "ignore" and "stop".
+COPY x from stdin (format CSV, log_verbosity verbos);  -- error, lists valid log_verbosity values
+ERROR:  COPY LOG_VERBOSITY "verbos" not recognized
+LINE 1: COPY x from stdin (format CSV, log_verbosity verbos);
+                                       ^
+HINT:  Valid values are "default", "silent", and "verbose".
 -- too many columns in column list: should fail
 COPY x (a, b, c, d, e, d, c) from stdin;
 ERROR:  column "d" specified more than once
diff --git a/src/test/regress/sql/copy2.sql b/src/test/regress/sql/copy2.sql
index cef45868db5..b8c9d2439ef 100644
--- a/src/test/regress/sql/copy2.sql
+++ b/src/test/regress/sql/copy2.sql
@@ -94,6 +94,13 @@ COPY x from stdin with (header -1);
 COPY x from stdin with (header 2.5);
 COPY x to stdout with (header 2);
 
+-- test error hints for invalid COPY options
+COPY x from stdin (foramt CSV);  -- error, suggests "format"
+COPY x from stdin (completely_invalid_option 'value');  -- error, no suggestion
+COPY x from stdin (format cvs);  -- error, lists valid formats
+COPY x from stdin (format CSV, on_error ignor);  -- error, lists valid on_error values
+COPY x from stdin (format CSV, log_verbosity verbos);  -- error, lists valid log_verbosity values
+
 -- too many columns in column list: should fail
 COPY x (a, b, c, d, e, d, c) from stdin;
 
-- 
2.50.1 (Apple Git-155)

From b7dd821ed89dcd2846169f46ff983e051b75ef5e Mon Sep 17 00:00:00 2001
From: Shinya Sugamoto <sugamoto@me.com>
Date: Fri, 5 Dec 2025 00:16:55 +0900
Subject: [PATCH] Add option name validation and hints for COPY command
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Add validation for COPY option names with helpful error messages:
- Suggest similar option names for typos (e.g., "foramt" -> "format")
- Show valid values for format, on_error, and log_verbosity options
- Internal options like convert_selectively are excluded from suggestions
---
 contrib/file_fdw/expected/file_fdw.out |  3 +
 src/backend/commands/copy.c            | 91 ++++++++++++++++++++++++--
 src/test/regress/expected/copy2.out    | 31 +++++++++
 src/test/regress/sql/copy2.sql         |  8 +++
 4 files changed, 128 insertions(+), 5 deletions(-)

diff --git a/contrib/file_fdw/expected/file_fdw.out b/contrib/file_fdw/expected/file_fdw.out
index 5121e27dce5..bf953c62a49 100644
--- a/contrib/file_fdw/expected/file_fdw.out
+++ b/contrib/file_fdw/expected/file_fdw.out
@@ -54,6 +54,7 @@ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS ("a=b" 'true');  -- ERROR
 ERROR:  invalid option name "a=b": must not contain "="
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'xml');  -- ERROR
 ERROR:  COPY format "xml" not recognized
+HINT:  Valid formats are "binary", "csv", and "text".
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'text', quote ':');          -- ERROR
 ERROR:  COPY QUOTE requires CSV mode
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'text', escape ':');         -- ERROR
@@ -96,10 +97,12 @@ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'csv', null '
 ERROR:  COPY null representation cannot use newline or carriage return
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (on_error 'unsupported');       -- ERROR
 ERROR:  COPY ON_ERROR "unsupported" not recognized
+HINT:  Valid values are "ignore" and "stop".
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'binary', on_error 'ignore');       -- ERROR
 ERROR:  only ON_ERROR STOP is allowed in BINARY mode
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (log_verbosity 'unsupported');       -- ERROR
 ERROR:  COPY LOG_VERBOSITY "unsupported" not recognized
+HINT:  Valid values are "default", "silent", and "verbose".
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (reject_limit '1');       -- ERROR
 ERROR:  COPY REJECT_LIMIT requires ON_ERROR to be set to IGNORE
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (on_error 'ignore', reject_limit '0');       -- ERROR
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 28e878c3688..1d48035e3e0 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -35,9 +35,83 @@
 #include "parser/parse_relation.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
+#include "utils/elog.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
 #include "utils/rls.h"
+#include "utils/varlena.h"
+
+/*
+ * List of valid COPY option names, used for validation and error hints.
+ *
+ * Options with suggest_in_hints=true will be suggested in error hints when a
+ * user specifies an unrecognized option name.  Internal/undocumented options
+ * should set this to false.
+ */
+typedef struct CopyOptionDef
+{
+	const char *name;
+	bool		suggest_in_hints;
+} CopyOptionDef;
+
+static const CopyOptionDef valid_copy_options[] = {
+	{"default", true},
+	{"delimiter", true},
+	{"encoding", true},
+	{"escape", true},
+	{"force_not_null", true},
+	{"force_null", true},
+	{"force_quote", true},
+	{"format", true},
+	{"freeze", true},
+	{"header", true},
+	{"log_verbosity", true},
+	{"null", true},
+	{"on_error", true},
+	{"quote", true},
+	{"reject_limit", true},
+	{"convert_selectively", false},	/* internal, undocumented */
+	{NULL, false}
+};
+
+/*
+ * Validate a COPY option name.
+ *
+ * If the option name is not recognized, report an error with a hint
+ * suggesting a similar valid option name if one exists.
+ */
+static void
+validate_copy_option(const char *option, ParseState *pstate, int location)
+{
+	ClosestMatchState match_state;
+	const char *closest_match;
+
+	/* Check if it's a valid option */
+	for (int i = 0; valid_copy_options[i].name != NULL; i++)
+	{
+		if (strcmp(valid_copy_options[i].name, option) == 0)
+			return;				/* valid option */
+	}
+
+	/*
+	 * Unknown option - build an error with a hint suggesting a similar option
+	 * name if there is one.
+	 */
+	initClosestMatch(&match_state, option, 4);
+	for (int i = 0; valid_copy_options[i].name != NULL; i++)
+	{
+		if (valid_copy_options[i].suggest_in_hints)
+			updateClosestMatch(&match_state, valid_copy_options[i].name);
+	}
+	closest_match = getClosestMatch(&match_state);
+
+	ereport(ERROR,
+			(errcode(ERRCODE_SYNTAX_ERROR),
+			 errmsg("option \"%s\" not recognized", option),
+			 closest_match ?
+			 errhint("Perhaps you meant \"%s\".", closest_match) : 0,
+			 parser_errposition(pstate, location)));
+}
 
 /*
  *	 DoCopy executes the SQL COPY statement
@@ -467,6 +541,7 @@ defGetCopyOnErrorChoice(DefElem *def, ParseState *pstate, bool is_from)
 			(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 	/*- translator: first %s is the name of a COPY option, e.g. ON_ERROR */
 			 errmsg("COPY %s \"%s\" not recognized", "ON_ERROR", sval),
+			 errhint("Valid values are \"%s\" and \"%s\".", "ignore", "stop"),
 			 parser_errposition(pstate, def->location)));
 	return COPY_ON_ERROR_STOP;	/* keep compiler quiet */
 }
@@ -525,6 +600,8 @@ defGetCopyLogVerbosityChoice(DefElem *def, ParseState *pstate)
 			(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 	/*- translator: first %s is the name of a COPY option, e.g. ON_ERROR */
 			 errmsg("COPY %s \"%s\" not recognized", "LOG_VERBOSITY", sval),
+			 errhint("Valid values are \"%s\", \"%s\", and \"%s\".",
+					 "default", "silent", "verbose"),
 			 parser_errposition(pstate, def->location)));
 	return COPY_LOG_VERBOSITY_DEFAULT;	/* keep compiler quiet */
 }
@@ -570,6 +647,9 @@ ProcessCopyOptions(ParseState *pstate,
 	{
 		DefElem    *defel = lfirst_node(DefElem, option);
 
+		/* Validate the option name; errors out if unrecognized */
+		validate_copy_option(defel->defname, pstate, defel->location);
+
 		if (strcmp(defel->defname, "format") == 0)
 		{
 			char	   *fmt = defGetString(defel);
@@ -587,6 +667,8 @@ ProcessCopyOptions(ParseState *pstate,
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
 						 errmsg("COPY format \"%s\" not recognized", fmt),
+						 errhint("Valid formats are \"%s\", \"%s\", and \"%s\".",
+								 "binary", "csv", "text"),
 						 parser_errposition(pstate, defel->location)));
 		}
 		else if (strcmp(defel->defname, "freeze") == 0)
@@ -731,11 +813,10 @@ ProcessCopyOptions(ParseState *pstate,
 			opts_out->reject_limit = defGetCopyRejectLimitOption(defel);
 		}
 		else
-			ereport(ERROR,
-					(errcode(ERRCODE_SYNTAX_ERROR),
-					 errmsg("option \"%s\" not recognized",
-							defel->defname),
-					 parser_errposition(pstate, defel->location)));
+			ereport(FATAL,
+					(errcode(ERRCODE_INTERNAL_ERROR),
+					 errmsg("unhandled COPY option \"%s\"", defel->defname)));
+		
 	}
 
 	/*
diff --git a/src/test/regress/expected/copy2.out b/src/test/regress/expected/copy2.out
index f3fdce23459..7480903023f 100644
--- a/src/test/regress/expected/copy2.out
+++ b/src/test/regress/expected/copy2.out
@@ -96,6 +96,7 @@ COPY x from stdin (on_error unsupported);
 ERROR:  COPY ON_ERROR "unsupported" not recognized
 LINE 1: COPY x from stdin (on_error unsupported);
                            ^
+HINT:  Valid values are "ignore" and "stop".
 COPY x from stdin (format TEXT, force_quote(a));
 ERROR:  COPY FORCE_QUOTE requires CSV mode
 COPY x from stdin (format TEXT, force_quote *);
@@ -128,6 +129,7 @@ COPY x from stdin (log_verbosity unsupported);
 ERROR:  COPY LOG_VERBOSITY "unsupported" not recognized
 LINE 1: COPY x from stdin (log_verbosity unsupported);
                            ^
+HINT:  Valid values are "default", "silent", and "verbose".
 COPY x from stdin with (reject_limit 1);
 ERROR:  COPY REJECT_LIMIT requires ON_ERROR to be set to IGNORE
 COPY x from stdin with (on_error ignore, reject_limit 0);
@@ -138,6 +140,35 @@ COPY x from stdin with (header 2.5);
 ERROR:  header requires a Boolean value, a non-negative integer, or the string "match"
 COPY x to stdout with (header 2);
 ERROR:  cannot use multi-line header in COPY TO
+-- test error hints for invalid COPY options
+COPY x from stdin (foramt CSV);  -- error, suggests "format"
+ERROR:  option "foramt" not recognized
+LINE 1: COPY x from stdin (foramt CSV);
+                           ^
+HINT:  Perhaps you meant "format".
+COPY x from stdin (convert_selectivel (a));  -- error, should NOT suggest convert_selectively
+ERROR:  option "convert_selectivel" not recognized
+LINE 1: COPY x from stdin (convert_selectivel (a));
+                           ^
+COPY x from stdin (completely_invalid_option 'value');  -- error, no suggestion
+ERROR:  option "completely_invalid_option" not recognized
+LINE 1: COPY x from stdin (completely_invalid_option 'value');
+                           ^
+COPY x from stdin (format cvs);  -- error, lists valid formats
+ERROR:  COPY format "cvs" not recognized
+LINE 1: COPY x from stdin (format cvs);
+                           ^
+HINT:  Valid formats are "binary", "csv", and "text".
+COPY x from stdin (format CSV, on_error ignor);  -- error, lists valid on_error values
+ERROR:  COPY ON_ERROR "ignor" not recognized
+LINE 1: COPY x from stdin (format CSV, on_error ignor);
+                                       ^
+HINT:  Valid values are "ignore" and "stop".
+COPY x from stdin (format CSV, log_verbosity verbos);  -- error, lists valid log_verbosity values
+ERROR:  COPY LOG_VERBOSITY "verbos" not recognized
+LINE 1: COPY x from stdin (format CSV, log_verbosity verbos);
+                                       ^
+HINT:  Valid values are "default", "silent", and "verbose".
 -- too many columns in column list: should fail
 COPY x (a, b, c, d, e, d, c) from stdin;
 ERROR:  column "d" specified more than once
diff --git a/src/test/regress/sql/copy2.sql b/src/test/regress/sql/copy2.sql
index cef45868db5..39d8e3fd992 100644
--- a/src/test/regress/sql/copy2.sql
+++ b/src/test/regress/sql/copy2.sql
@@ -94,6 +94,14 @@ COPY x from stdin with (header -1);
 COPY x from stdin with (header 2.5);
 COPY x to stdout with (header 2);
 
+-- test error hints for invalid COPY options
+COPY x from stdin (foramt CSV);  -- error, suggests "format"
+COPY x from stdin (convert_selectivel (a));  -- error, should NOT suggest convert_selectively
+COPY x from stdin (completely_invalid_option 'value');  -- error, no suggestion
+COPY x from stdin (format cvs);  -- error, lists valid formats
+COPY x from stdin (format CSV, on_error ignor);  -- error, lists valid on_error values
+COPY x from stdin (format CSV, log_verbosity verbos);  -- error, lists valid log_verbosity values
+
 -- too many columns in column list: should fail
 COPY x (a, b, c, d, e, d, c) from stdin;
 
-- 
2.50.1 (Apple Git-155)