Fix overly-strict sanity check in BeginInternalSubTransaction that made it

fail when used in a deferred trigger.  Bug goes back to 8.0; no doubt the
reason it hadn't been noticed is that we've been discouraging use of
user-defined constraint triggers.  Per report from Frank van Vugt.

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index c16b4fa6be9261dfb2d12f6db29a98fd91ae7d4a..000c72f8de1933a8a54d74cbe998be9a91773198 100644 (file)
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *   $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.243 2007/05/27 03:50:39 tgl Exp $
+ *   $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.244 2007/05/30 21:01:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3348,10 +3348,11 @@ RollbackToSavepoint(List *options)
 
 /*
  * BeginInternalSubTransaction
- *     This is the same as DefineSavepoint except it allows TBLOCK_STARTED
- *     state, and therefore it can safely be used in a function that might
- *     be called when not inside a BEGIN block.  Also, we automatically
- *     cycle through CommitTransactionCommand/StartTransactionCommand
+ *     This is the same as DefineSavepoint except it allows TBLOCK_STARTED,
+ *     TBLOCK_END, and TBLOCK_PREPARE states, and therefore it can safely be
+ *     used in functions that might be called when not inside a BEGIN block
+ *     or when running deferred triggers at COMMIT/PREPARE time.  Also, it
+ *     automatically does CommitTransactionCommand/StartTransactionCommand
  *     instead of expecting the caller to do it.
  */
 void
@@ -3363,6 +3364,8 @@ BeginInternalSubTransaction(char *name)
    {
        case TBLOCK_STARTED:
        case TBLOCK_INPROGRESS:
+       case TBLOCK_END:
+       case TBLOCK_PREPARE:
        case TBLOCK_SUBINPROGRESS:
            /* Normal subtransaction start */
            PushTransaction();
@@ -3380,7 +3383,6 @@ BeginInternalSubTransaction(char *name)
        case TBLOCK_DEFAULT:
        case TBLOCK_BEGIN:
        case TBLOCK_SUBBEGIN:
-       case TBLOCK_END:
        case TBLOCK_SUBEND:
        case TBLOCK_ABORT:
        case TBLOCK_SUBABORT:
@@ -3390,7 +3392,6 @@ BeginInternalSubTransaction(char *name)
        case TBLOCK_SUBABORT_PENDING:
        case TBLOCK_SUBRESTART:
        case TBLOCK_SUBABORT_RESTART:
-       case TBLOCK_PREPARE:
            elog(FATAL, "BeginInternalSubTransaction: unexpected state %s",
                 BlockStateAsString(s->blockState));
            break;