From 133ee1f88ec2ca732bfc6084e99a7f7d4a2710c5 Mon Sep 17 00:00:00 2001 From: Jelte Fennema-Nio Date: Mon, 16 Dec 2024 14:33:46 +0100 Subject: [PATCH v2] Use last string-literal subscript as default column name --- src/backend/parser/parse_clause.c | 4 +- src/backend/parser/parse_expr.c | 2 +- src/backend/parser/parse_target.c | 128 +++++++++++++++++++++++++---- src/backend/parser/parse_utilcmd.c | 10 ++- src/include/parser/parse_target.h | 4 +- 5 files changed, 123 insertions(+), 25 deletions(-) diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c index 979926b605..8008e51a2f 100644 --- a/src/backend/parser/parse_clause.c +++ b/src/backend/parser/parse_clause.c @@ -571,7 +571,7 @@ transformRangeFunction(ParseState *pstate, RangeFunction *r) funcexprs = lappend(funcexprs, newfexpr); funcnames = lappend(funcnames, - FigureColname((Node *) newfc)); + FigureColname((Node *) newfc, (Expr *) newfexpr)); /* coldeflist is empty, so no error is possible */ @@ -599,7 +599,7 @@ transformRangeFunction(ParseState *pstate, RangeFunction *r) funcexprs = lappend(funcexprs, newfexpr); funcnames = lappend(funcnames, - FigureColname(fexpr)); + FigureColname(fexpr, (Expr *) newfexpr)); if (coldeflist && r->coldeflist) ereport(ERROR, diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index c2806297aa..cdc0bf229f 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -2377,7 +2377,7 @@ transformXmlExpr(ParseState *pstate, XmlExpr *x) if (r->name) argname = map_sql_identifier_to_xml_name(r->name, false, false); else if (IsA(r->val, ColumnRef)) - argname = map_sql_identifier_to_xml_name(FigureColname(r->val), + argname = map_sql_identifier_to_xml_name(FigureColname(r->val, (Expr *) expr), true, false); else { diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c index 76bf88c3ca..10996e0083 100644 --- a/src/backend/parser/parse_target.c +++ b/src/backend/parser/parse_target.c @@ -55,7 +55,8 @@ static List *ExpandSingleTable(ParseState *pstate, ParseNamespaceItem *nsitem, bool make_target_entry); static List *ExpandRowReference(ParseState *pstate, Node *expr, bool make_target_entry); -static int FigureColnameInternal(Node *node, char **name); +static char *FigureColnameTransformed(Expr *expr); +static int FigureColnameUntransformed(Node *node, char **name); /* @@ -99,7 +100,7 @@ transformTargetEntry(ParseState *pstate, * Generate a suitable column name for a column without any explicit * 'AS ColumnName' clause. */ - colname = FigureColname(node); + colname = FigureColname(node, (Expr *) expr); } return makeTargetEntry((Expr *) expr, @@ -1706,15 +1707,25 @@ expandRecordVariable(ParseState *pstate, Var *var, int levelsup) * list, we have to guess a suitable name. The SQL spec provides some * guidance, but not much... * - * Note that the argument is the *untransformed* parse tree for the target - * item. This is a shade easier to work with than the transformed tree. + * Note that this requires both the *untransformed* and the *transformed* parse + * tree. The untransformed is generally easier to work with than the + * transformed one, but in some cases we need the details. */ char * -FigureColname(Node *node) +FigureColname(Node *untransformed, Expr *transformed) { char *name = NULL; - (void) FigureColnameInternal(node, &name); + /* + * XXX: Could add hook here that receives both transform and untransformed + * to allow extensions to create arbitrary column names + */ + + name = FigureColnameTransformed(transformed); + if (name != NULL) + return name; + + (void) FigureColnameUntransformed(untransformed, &name); if (name != NULL) return name; /* default result if we can't guess anything */ @@ -1729,16 +1740,100 @@ FigureColname(Node *node) * we can't pick a good name. */ char * -FigureIndexColname(Node *node) +FigureIndexColname(Node *untransformed, Expr *transformed) { char *name = NULL; - (void) FigureColnameInternal(node, &name); + /* + * XXX: Could add hook here to allow extensions to create arbitrary column + * names + */ + + name = FigureColnameTransformed(transformed); + if (name != NULL) + return name; + + (void) FigureColnameUntransformed(untransformed, &name); return name; } +char * +FigureColnameTransformed(Expr *expr) +{ + if (expr == NULL) + return NULL; + + switch (nodeTag(expr)) + { + case T_SubscriptingRef: + { + SubscriptingRef *sbsref = (SubscriptingRef *) expr; + char *name = NULL; + + /* + * XXX: Could add a hook here based on the type of + * refcontainertype and getSubscriptingRoutines. + */ + + if (sbsref->reflowerindexpr != NIL) + return NULL; + + foreach_ptr(Node, upper, sbsref->refupperindexpr) + { + Const *constExpr; + + if (!IsA(upper, Const)) + continue; + constExpr = (Const *) upper; + + if (constExpr->constisnull) + return NULL; + + if (constExpr->consttype != TEXTOID) + return NULL; + + name = TextDatumGetCString(constExpr->constvalue); + } + return name; + + } + break; + case T_CoerceViaIO: + { + CoerceViaIO *cvi = (CoerceViaIO *) expr; + + return FigureColnameTransformed(cvi->arg); + } + break; + case T_RelabelType: + { + RelabelType *cvi = (RelabelType *) expr; + + return FigureColnameTransformed(cvi->arg); + } + break; + case T_ArrayCoerceExpr: + { + ArrayCoerceExpr *cvi = (ArrayCoerceExpr *) expr; + + return FigureColnameTransformed(cvi->arg); + } + break; + case T_ConvertRowtypeExpr: + { + ConvertRowtypeExpr *cvi = (ConvertRowtypeExpr *) expr; + + return FigureColnameTransformed(cvi->arg); + } + break; + default: + return NULL; + } + return NULL; +} + /* - * FigureColnameInternal - + * FigureColnameUntransformed - * internal workhorse for FigureColname * * Return value indicates strength of confidence in result: @@ -1749,7 +1844,7 @@ FigureIndexColname(Node *node) * If the result isn't zero, *name is set to the chosen name. */ static int -FigureColnameInternal(Node *node, char **name) +FigureColnameUntransformed(Node *node, char **name) { int strength = 0; @@ -1791,13 +1886,14 @@ FigureColnameInternal(Node *node, char **name) if (IsA(i, String)) fname = strVal(i); + } if (fname) { *name = fname; return 2; } - return FigureColnameInternal(ind->arg, name); + return FigureColnameUntransformed(ind->arg, name); } break; case T_FuncCall: @@ -1812,8 +1908,8 @@ FigureColnameInternal(Node *node, char **name) } break; case T_TypeCast: - strength = FigureColnameInternal(((TypeCast *) node)->arg, - name); + strength = FigureColnameUntransformed(((TypeCast *) node)->arg, + name); if (strength <= 1) { if (((TypeCast *) node)->typeName != NULL) @@ -1824,7 +1920,7 @@ FigureColnameInternal(Node *node, char **name) } break; case T_CollateClause: - return FigureColnameInternal(((CollateClause *) node)->arg, name); + return FigureColnameUntransformed(((CollateClause *) node)->arg, name); case T_GroupingFunc: /* make GROUPING() act like a regular function */ *name = "grouping"; @@ -1877,8 +1973,8 @@ FigureColnameInternal(Node *node, char **name) } break; case T_CaseExpr: - strength = FigureColnameInternal((Node *) ((CaseExpr *) node)->defresult, - name); + strength = FigureColnameUntransformed((Node *) ((CaseExpr *) node)->defresult, + name); if (strength <= 1) { *name = "case"; diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c index 0f324ee4e3..dc947d6590 100644 --- a/src/backend/parser/parse_utilcmd.c +++ b/src/backend/parser/parse_utilcmd.c @@ -3059,13 +3059,15 @@ transformIndexStmt(Oid relid, IndexStmt *stmt, const char *queryString) if (ielem->expr) { + /* Now do parse transformation of the expression */ + Node *transformed = transformExpr(pstate, ielem->expr, + EXPR_KIND_INDEX_EXPRESSION); + /* Extract preliminary index col name before transforming expr */ if (ielem->indexcolname == NULL) - ielem->indexcolname = FigureIndexColname(ielem->expr); + ielem->indexcolname = FigureIndexColname(ielem->expr, (Expr *) transformed); - /* Now do parse transformation of the expression */ - ielem->expr = transformExpr(pstate, ielem->expr, - EXPR_KIND_INDEX_EXPRESSION); + ielem->expr = transformed; /* We have to fix its collations too */ assign_expr_collations(pstate, ielem->expr); diff --git a/src/include/parser/parse_target.h b/src/include/parser/parse_target.h index 3281f63494..5d9f670549 100644 --- a/src/include/parser/parse_target.h +++ b/src/include/parser/parse_target.h @@ -52,7 +52,7 @@ extern List *checkInsertTargets(ParseState *pstate, List *cols, List **attrnos); extern TupleDesc expandRecordVariable(ParseState *pstate, Var *var, int levelsup); -extern char *FigureColname(Node *node); -extern char *FigureIndexColname(Node *node); +extern char *FigureColname(Node *untransformed, Expr *transformed); +extern char *FigureIndexColname(Node *untransformed, Expr *transformed); #endif /* PARSE_TARGET_H */ base-commit: 39240bcad56dc51a7896d04a1e066efcf988b58f -- 2.43.0