From d74189febc751302f13009d69bebd763c8a23f58 Mon Sep 17 00:00:00 2001
From: amit <amitlangote09@gmail.com>
Date: Mon, 13 Feb 2017 16:10:17 +0900
Subject: [PATCH] Unbreak ALTER TABLE DETACH PARTITION

DETACH PARTITION should throw error much sooner if the specified
(parent) table is not a partitioned table.  In case of ATTACH
PARTITION that's done during transformAlterTableStmt.  Do the same
for DETACH PARTITION.  Instead of inventing a transformDetachPartition,
rename the existing transformAttachPartition to transformPartitionCmd
and have it serve both cases.
---
 src/backend/parser/parse_utilcmd.c        | 29 +++++++++++++++++++----------
 src/test/regress/expected/alter_table.out |  5 +++++
 src/test/regress/sql/alter_table.sql      |  5 +++++
 3 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 0f78abaae2..efbd205b63 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -133,7 +133,7 @@ static void transformConstraintAttrs(CreateStmtContext *cxt,
 						 List *constraintList);
 static void transformColumnType(CreateStmtContext *cxt, ColumnDef *column);
 static void setSchemaName(char *context_schema, char **stmt_schema_name);
-static void transformAttachPartition(CreateStmtContext *cxt, PartitionCmd *cmd);
+static void transformPartitionCmd(CreateStmtContext *cxt, PartitionCmd *cmd);
 
 
 /*
@@ -2654,13 +2654,18 @@ transformAlterTableStmt(Oid relid, AlterTableStmt *stmt,
 				}
 
 			case AT_AttachPartition:
+			case AT_DetachPartition:
 				{
 					PartitionCmd *partcmd = (PartitionCmd *) cmd->def;
 
-					transformAttachPartition(&cxt, partcmd);
+					transformPartitionCmd(&cxt, partcmd);
 
-					/* assign transformed values */
-					partcmd->bound = cxt.partbound;
+					/*
+					 * Assign transformed value of the partition bound, if
+					 * any.
+					 */
+					if (cxt.partbound != NULL)
+						partcmd->bound = cxt.partbound;
 				}
 
 				newcmds = lappend(newcmds, cmd);
@@ -3032,11 +3037,14 @@ setSchemaName(char *context_schema, char **stmt_schema_name)
 }
 
 /*
- * transformAttachPartition
- *		Analyze ATTACH PARTITION ... FOR VALUES ...
+ * transformPartitionCmd
+ *		Analyze the ATTACH/DETACH PARTITION command
+ *
+ * In case of the ATTACH PARTITION command, cxt->partbound is set to the
+ * transformed value of cmd->bound.
  */
 static void
-transformAttachPartition(CreateStmtContext *cxt, PartitionCmd *cmd)
+transformPartitionCmd(CreateStmtContext *cxt, PartitionCmd *cmd)
 {
 	Relation	parentRel = cxt->rel;
 
@@ -3050,10 +3058,11 @@ transformAttachPartition(CreateStmtContext *cxt, PartitionCmd *cmd)
 				 errmsg("\"%s\" is not partitioned",
 						RelationGetRelationName(parentRel))));
 
-	/* transform the values */
+	/* transform the partition bound, if any */
 	Assert(RelationGetPartitionKey(parentRel) != NULL);
-	cxt->partbound = transformPartitionBound(cxt->pstate, parentRel,
-											 cmd->bound);
+	if (cmd->bound != NULL)
+		cxt->partbound = transformPartitionBound(cxt->pstate, parentRel,
+												 cmd->bound);
 }
 
 /*
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index d8e7b61294..33f820a245 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -3255,6 +3255,11 @@ DETAIL:  "list_parted2" is already a child of "list_parted2".
 --
 -- DETACH PARTITION
 --
+-- check that the table is partitioned at all
+CREATE TABLE regular_table (a int);
+ALTER TABLE regular_table DETACH PARTITION any_name;
+ERROR:  "regular_table" is not partitioned
+DROP TABLE regular_table;
 -- check that the partition being detached exists at all
 ALTER TABLE list_parted2 DETACH PARTITION part_4;
 ERROR:  relation "part_4" does not exist
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 1f551ec53c..a2baf0f2a0 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -2134,6 +2134,11 @@ ALTER TABLE list_parted2 ATTACH PARTITION list_parted2 FOR VALUES IN (0);
 -- DETACH PARTITION
 --
 
+-- check that the table is partitioned at all
+CREATE TABLE regular_table (a int);
+ALTER TABLE regular_table DETACH PARTITION any_name;
+DROP TABLE regular_table;
+
 -- check that the partition being detached exists at all
 ALTER TABLE list_parted2 DETACH PARTITION part_4;
 
-- 
2.11.0