Remove MsgType type

From b74e5ff37ce648639d662600a392e12a8c9b44f4 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 3 Jul 2025 14:46:17 +0200
Subject: [PATCH] Remove MsgType type

Presumably, this type was meant to hold the protocol message type in
the pre-version-3 era, but this was never even fully developed then,
and the name is pretty confusing nowadays.  It has only one vestigial
use that we can get rid of.  Since a cancel request is indicated by a
special protocol version number, we can use the ProtocolVersion type,
which MsgType was based on.  (If this is also found confusing, we
could also use uint32 directly.)
---
 src/include/libpq/pqcomm.h       | 3 +--
 src/interfaces/libpq/fe-cancel.c | 4 ++--
 src/tools/pgindent/typedefs.list | 1 -
 3 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/include/libpq/pqcomm.h b/src/include/libpq/pqcomm.h
index 625f4b43879..235f6ed7d0d 100644
--- a/src/include/libpq/pqcomm.h
+++ b/src/include/libpq/pqcomm.h
@@ -114,7 +114,6 @@ is_unixsock_path(const char *path)
 
 
 typedef uint32 ProtocolVersion; /* FE/BE protocol version number */
-typedef ProtocolVersion MsgType;
 
 
 /*
@@ -146,7 +145,7 @@ typedef uint32 AuthRequest;		/* an AUTH_REQ_* code */
 typedef struct CancelRequestPacket
 {
 	/* Note that each field is stored in network byte order! */
-	MsgType		cancelRequestCode;	/* code to identify a cancel request */
+	ProtocolVersion cancelRequestCode;	/* code to identify a cancel request */
 	uint32		backendPID;		/* PID of client's backend */
 	uint8		cancelAuthCode[FLEXIBLE_ARRAY_MEMBER];	/* secret key to
 														 * authorize cancel */
diff --git a/src/interfaces/libpq/fe-cancel.c b/src/interfaces/libpq/fe-cancel.c
index c872a0267f0..f23caf8349d 100644
--- a/src/interfaces/libpq/fe-cancel.c
+++ b/src/interfaces/libpq/fe-cancel.c
@@ -448,7 +448,7 @@ PQgetCancel(PGconn *conn)
 	}
 
 	req = (CancelRequestPacket *) &cancel->cancel_req;
-	req->cancelRequestCode = (MsgType) pg_hton32(CANCEL_REQUEST_CODE);
+	req->cancelRequestCode = pg_hton32(CANCEL_REQUEST_CODE);
 	req->backendPID = pg_hton32(conn->be_pid);
 	memcpy(req->cancelAuthCode, conn->be_cancel_key, conn->be_cancel_key_len);
 	/* include the length field itself in the length */
@@ -479,7 +479,7 @@ PQsendCancelRequest(PGconn *cancelConn)
 
 	/* Send the message body. */
 	memset(&req, 0, offsetof(CancelRequestPacket, cancelAuthCode));
-	req.cancelRequestCode = (MsgType) pg_hton32(CANCEL_REQUEST_CODE);
+	req.cancelRequestCode = pg_hton32(CANCEL_REQUEST_CODE);
 	req.backendPID = pg_hton32(cancelConn->be_pid);
 	if (pqPutnchar(&req, offsetof(CancelRequestPacket, cancelAuthCode), cancelConn))
 		return STATUS_ERROR;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 9dd65b10254..792042e4961 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -1722,7 +1722,6 @@ ModifyTablePath
 ModifyTableState
 MonotonicFunction
 MorphOpaque
-MsgType
 MultiAssignRef
 MultiSortSupport
 MultiSortSupportData
-- 
2.52.0