fix: Use full ENR name for temp tables in ATParseTransformCmd

ATParseTransformCmd reconstructs the AlterTableStmt RangeVar from
RelationGetRelationName(rel), which returns NameStr(rel->rd_rel->relname).
The Name type is capped at NAMEDATALEN-1 (63 chars), so temp table names
>= 64 chars get clipped. This causes subsequent RangeVarGetRelidExtended
calls to fail because the clipped name doesn't match the full name stored
in ENR.

Fix: For T-SQL #temp tables, look up the full untruncated name from ENR
using get_ENR_withoid and use it as the RangeVar relname instead.

Signed-off-by: anju15bharti <abanju@amazon.com>

Author: anju15bharti

src/backend/commands/tablecmds.c

@@ -5834,6 +5834,23 @@ ATParseTransformCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 		makeRangeVar(get_namespace_name(RelationGetNamespace(rel)),
 					 pstrdup(RelationGetRelationName(rel)),
 					 -1);
+
+	/*
+	 * For T-SQL #temp tables with long names (>= NAMEDATALEN), the relation
+	 * descriptor stores the name clipped to NAMEDATALEN-1 (63 chars) due to the
+	 * Name type limitation. However, ENR stores the full untruncated name which
+	 * is what subsequent lookups via RangeVarGetRelidExtended need to match.
+	 * Replace the clipped relname with the full name from ENR.
+	 */
+	if (sql_dialect == SQL_DIALECT_TSQL &&
+		RelationGetRelationName(rel)[0] == '#')
+	{
+		EphemeralNamedRelation enr = get_ENR_withoid(currentQueryEnv,
+													RelationGetRelid(rel),
+													ENR_TSQL_TEMP, true);
+		if (enr)
+			atstmt->relation->relname = pstrdup(enr->md.name);
+	}
 	atstmt->relation->inh = recurse;
 	atstmt->cmds = list_make1(cmd);
 	atstmt->objtype = OBJECT_TABLE; /* needn't be picky here */