Fix a number of places that produced XX000 errors in the regression tests.

It's against project policy to use elog() for user-facing errors, or to
omit an errcode() selection for errors that aren't supposed to be "can't
happen" cases.  Fix all the violations of this policy that result in
ERRCODE_INTERNAL_ERROR log entries during the standard regression tests,
as errors that can reliably be triggered from SQL surely should be
considered user-facing.

I also looked through all the files touched by this commit and fixed
other nearby problems of the same ilk.  I do not claim to have fixed
all violations of the policy, just the ones in these files.

In a few places I also changed existing ERRCODE choices that didn't
seem particularly appropriate; mainly replacing ERRCODE_SYNTAX_ERROR
by something more specific.

Back-patch to 9.5, but no further; changing ERRCODE assignments in
stable branches doesn't seem like a good idea.

6 files changed, 56 insertions, 27 deletions

diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 8176b6a6d41..180f529060d 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -484,7 +484,7 @@ allocate_reloption(bits32 kinds, int type, char *name, char *desc)
 			size = sizeof(relopt_string);
 			break;
 		default:
-			elog(ERROR, "unsupported option type");
+			elog(ERROR, "unsupported reloption type %d", type);
 			return NULL;		/* keep compiler quiet */
 	}
 
@@ -1016,7 +1016,8 @@ parse_one_reloption(relopt_value *option, char *text_str, int text_len,
 				parsed = parse_bool(value, &option->values.bool_val);
 				if (validate && !parsed)
 					ereport(ERROR,
-					   (errmsg("invalid value for boolean option \"%s\": %s",
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						errmsg("invalid value for boolean option \"%s\": %s",
 							   option->gen->name, value)));
 			}
 			break;
@@ -1027,12 +1028,14 @@ parse_one_reloption(relopt_value *option, char *text_str, int text_len,
 				parsed = parse_int(value, &option->values.int_val, 0, NULL);
 				if (validate && !parsed)
 					ereport(ERROR,
-					   (errmsg("invalid value for integer option \"%s\": %s",
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						errmsg("invalid value for integer option \"%s\": %s",
 							   option->gen->name, value)));
 				if (validate && (option->values.int_val < optint->min ||
 								 option->values.int_val > optint->max))
 					ereport(ERROR,
-						  (errmsg("value %s out of bounds for option \"%s\"",
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						   errmsg("value %s out of bounds for option \"%s\"",
 								  value, option->gen->name),
 					 errdetail("Valid values are between \"%d\" and \"%d\".",
 							   optint->min, optint->max)));
@@ -1045,12 +1048,14 @@ parse_one_reloption(relopt_value *option, char *text_str, int text_len,
 				parsed = parse_real(value, &option->values.real_val);
 				if (validate && !parsed)
 					ereport(ERROR,
-							(errmsg("invalid value for floating point option \"%s\": %s",
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							 errmsg("invalid value for floating point option \"%s\": %s",
 									option->gen->name, value)));
 				if (validate && (option->values.real_val < optreal->min ||
 								 option->values.real_val > optreal->max))
 					ereport(ERROR,
-						  (errmsg("value %s out of bounds for option \"%s\"",
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						   errmsg("value %s out of bounds for option \"%s\"",
 								  value, option->gen->name),
 					 errdetail("Valid values are between \"%f\" and \"%f\".",
 							   optreal->min, optreal->max)));
@@ -1168,7 +1173,7 @@ fillRelOptions(void *rdopts, Size basesize,
 						}
 						break;
 					default:
-						elog(ERROR, "unrecognized reloption type %c",
+						elog(ERROR, "unsupported reloption type %d",
 							 options[i].gen->type);
 						break;
 				}
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 050efdc4806..3701d8e59d5 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2801,7 +2801,9 @@ l1:
 	if (result == HeapTupleInvisible)
 	{
 		UnlockReleaseBuffer(buffer);
-		elog(ERROR, "attempted to delete invisible tuple");
+		ereport(ERROR,
+				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				 errmsg("attempted to delete invisible tuple")));
 	}
 	else if (result == HeapTupleBeingUpdated && wait)
 	{
@@ -3343,7 +3345,9 @@ l2:
 	if (result == HeapTupleInvisible)
 	{
 		UnlockReleaseBuffer(buffer);
-		elog(ERROR, "attempted to update invisible tuple");
+		ereport(ERROR,
+				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				 errmsg("attempted to update invisible tuple")));
 	}
 	else if (result == HeapTupleBeingUpdated && wait)
 	{
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 47dd3accafe..8db1b35fe82 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -1422,9 +1422,9 @@ BeginCopy(bool is_from,
 		 * in any RLS clauses.
 		 *
 		 * When this happens, we are passed in the relid of the originally
-		 * found relation (which we have locked).  As the planner will look
-		 * up the relation again, we double-check here to make sure it found
-		 * the same one that we have locked.
+		 * found relation (which we have locked).  As the planner will look up
+		 * the relation again, we double-check here to make sure it found the
+		 * same one that we have locked.
 		 */
 		if (queryRelId != InvalidOid)
 		{
@@ -1603,10 +1603,12 @@ ClosePipeToProgram(CopyState cstate)
 	pclose_rc = ClosePipeStream(cstate->copy_file);
 	if (pclose_rc == -1)
 		ereport(ERROR,
-				(errmsg("could not close pipe to external command: %m")));
+				(errcode_for_file_access(),
+				 errmsg("could not close pipe to external command: %m")));
 	else if (pclose_rc != 0)
 		ereport(ERROR,
-				(errmsg("program \"%s\" failed",
+				(errcode(ERRCODE_EXTERNAL_ROUTINE_EXCEPTION),
+				 errmsg("program \"%s\" failed",
 						cstate->filename),
 				 errdetail_internal("%s", wait_result_to_str(pclose_rc))));
 }
@@ -1703,7 +1705,8 @@ BeginCopyTo(Relation rel,
 			cstate->copy_file = OpenPipeStream(cstate->filename, PG_BINARY_W);
 			if (cstate->copy_file == NULL)
 				ereport(ERROR,
-						(errmsg("could not execute command \"%s\": %m",
+						(errcode_for_file_access(),
+						 errmsg("could not execute command \"%s\": %m",
 								cstate->filename)));
 		}
 		else
@@ -1730,7 +1733,10 @@ BeginCopyTo(Relation rel,
 								cstate->filename)));
 
 			if (fstat(fileno(cstate->copy_file), &st))
-				elog(ERROR, "could not stat file \"%s\": %m", cstate->filename);
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not stat file \"%s\": %m",
+								cstate->filename)));
 
 			if (S_ISDIR(st.st_mode))
 				ereport(ERROR,
@@ -2271,13 +2277,13 @@ CopyFrom(CopyState cstate)
 	{
 		if (!ThereAreNoPriorRegisteredSnapshots() || !ThereAreNoReadyPortals())
 			ereport(ERROR,
-					(ERRCODE_INVALID_TRANSACTION_STATE,
+					(errcode(ERRCODE_INVALID_TRANSACTION_STATE),
 					 errmsg("cannot perform FREEZE because of prior transaction activity")));
 
 		if (cstate->rel->rd_createSubid != GetCurrentSubTransactionId() &&
 		 cstate->rel->rd_newRelfilenodeSubid != GetCurrentSubTransactionId())
 			ereport(ERROR,
-					(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE,
+					(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 					 errmsg("cannot perform FREEZE because the table was not created or truncated in the current subtransaction")));
 
 		hi_options |= HEAP_INSERT_FROZEN;
@@ -2737,7 +2743,8 @@ BeginCopyFrom(Relation rel,
 			cstate->copy_file = OpenPipeStream(cstate->filename, PG_BINARY_R);
 			if (cstate->copy_file == NULL)
 				ereport(ERROR,
-						(errmsg("could not execute command \"%s\": %m",
+						(errcode_for_file_access(),
+						 errmsg("could not execute command \"%s\": %m",
 								cstate->filename)));
 		}
 		else
@@ -2752,7 +2759,10 @@ BeginCopyFrom(Relation rel,
 								cstate->filename)));
 
 			if (fstat(fileno(cstate->copy_file), &st))
-				elog(ERROR, "could not stat file \"%s\": %m", cstate->filename);
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not stat file \"%s\": %m",
+								cstate->filename)));
 
 			if (S_ISDIR(st.st_mode))
 				ereport(ERROR,
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index baf66f1e6c0..85b04832479 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -180,7 +180,10 @@ vacuum(int options, RangeVar *relation, Oid relid, VacuumParams *params,
 	 * calls a hostile index expression that itself calls ANALYZE.
 	 */
 	if (in_vacuum)
-		elog(ERROR, "%s cannot be executed from VACUUM or ANALYZE", stmttype);
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("%s cannot be executed from VACUUM or ANALYZE",
+						stmttype)));
 
 	/*
 	 * Send info about dead objects to the statistics collector, unless we are
diff --git a/src/backend/executor/execQual.c b/src/backend/executor/execQual.c
index 0f911f210bf..16bc8fa5f6c 100644
--- a/src/backend/executor/execQual.c
+++ b/src/backend/executor/execQual.c
@@ -631,7 +631,8 @@ ExecEvalScalarVar(ExprState *exprstate, ExprContext *econtext,
 		{
 			if (variable->vartype != attr->atttypid)
 				ereport(ERROR,
-						(errmsg("attribute %d has wrong type", attnum),
+						(errcode(ERRCODE_DATATYPE_MISMATCH),
+						 errmsg("attribute %d has wrong type", attnum),
 						 errdetail("Table has type %s, but query expects %s.",
 								   format_type_be(attr->atttypid),
 								   format_type_be(variable->vartype))));
@@ -4111,7 +4112,8 @@ ExecEvalFieldSelect(FieldSelectState *fstate,
 	/* As in ExecEvalScalarVar, we should but can't check typmod */
 	if (fselect->resulttype != attr->atttypid)
 		ereport(ERROR,
-				(errmsg("attribute %d has wrong type", fieldnum),
+				(errcode(ERRCODE_DATATYPE_MISMATCH),
+				 errmsg("attribute %d has wrong type", fieldnum),
 				 errdetail("Table has type %s, but query expects %s.",
 						   format_type_be(attr->atttypid),
 						   format_type_be(fselect->resulttype))));
diff --git a/src/backend/utils/adt/txid.c b/src/backend/utils/adt/txid.c
index ce1d9abddea..ba4b48298fd 100644
--- a/src/backend/utils/adt/txid.c
+++ b/src/backend/utils/adt/txid.c
@@ -334,8 +334,11 @@ parse_snapshot(const char *str)
 	return buf_finalize(buf);
 
 bad_format:
-	elog(ERROR, "invalid input for txid_snapshot: \"%s\"", str_start);
-	return NULL;
+	ereport(ERROR,
+			(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+			 errmsg("invalid input syntax for type txid_snapshot: \"%s\"",
+					str_start)));
+	return NULL;				/* keep compiler quiet */
 }
 
 /*
@@ -526,8 +529,10 @@ txid_snapshot_recv(PG_FUNCTION_ARGS)
 	PG_RETURN_POINTER(snap);
 
 bad_format:
-	elog(ERROR, "invalid snapshot data");
-	return (Datum) NULL;
+	ereport(ERROR,
+			(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
+			 errmsg("invalid external txid_snapshot data")));
+	PG_RETURN_POINTER(NULL);	/* keep compiler quiet */
 }
 
 /*