Fix pg_dump for inherited validated not-null constraints

When a child constraint is validated and the parent constraint it
derives from isn't, pg_dump must be coerced into printing the child
constraint; failing to do would result in a dump that restores the
constraint as not valid, which would be incorrect.

Co-authored-by: jian he <jian.universality@gmail.com>
Co-authored-by: Álvaro Herrera <alvherre@kurilemu.de>
Reported-by: jian he <jian.universality@gmail.com>
Message-id: https://postgr.es/m/CACJufxGHNNMc0E2JphUqJMzD3=bwRSuAEVBF5ekgkG8uY0Q3hg@mail.gmail.com

src/bin/pg_dump/common.c

@@ -453,8 +453,8 @@ flagInhIndexes(Archive *fout, TableInfo tblinfo[], int numTables)
  * What we need to do here is:
  *
  * - Detect child columns that inherit NOT NULL bits from their parents, so
- *   that we needn't specify that again for the child. (Versions >= 18 no
- *   longer need this.)
+ *   that we needn't specify that again for the child.  For versions 18 and
+ *   up, this is needed when the parent is NOT VALID and the child isn't.
  *
  * - Detect child columns that have DEFAULT NULL when their parents had some
  *   non-null default.  In this case, we make up a dummy AttrDefInfo object so
@@ -516,6 +516,8 @@ flagInhAttrs(Archive *fout, DumpOptions *dopt, TableInfo *tblinfo, int numTables
 			bool		foundDefault;	/* Found a default in a parent */
 			bool		foundSameGenerated; /* Found matching GENERATED */
 			bool		foundDiffGenerated; /* Found non-matching GENERATED */
+			bool		allNotNullsInvalid = true;	/* is NOT NULL NOT VALID
+													 * on all parents? */
 
 			/* no point in examining dropped columns */
 			if (tbinfo->attisdropped[j])
@@ -546,6 +548,18 @@ flagInhAttrs(Archive *fout, DumpOptions *dopt, TableInfo *tblinfo, int numTables
 						parent->notnull_constrs[inhAttrInd] != NULL)
 						foundNotNull = true;
 
+					/*
+					 * Keep track of whether all the parents that have a
+					 * not-null constraint on this column have it as NOT
+					 * VALID; if they all are, arrange to have it printed for
+					 * this column.  If at least one parent has it as valid,
+					 * there's no need.
+					 */
+					if (fout->remoteVersion >= 180000 &&
+						parent->notnull_constrs[inhAttrInd] &&
+						!parent->notnull_invalid[inhAttrInd])
+						allNotNullsInvalid = false;
+
 					foundDefault |= (parentDef != NULL &&
 									 strcmp(parentDef->adef_expr, "NULL") != 0 &&
 									 !parent->attgenerated[inhAttrInd]);
@@ -571,6 +585,14 @@ flagInhAttrs(Archive *fout, DumpOptions *dopt, TableInfo *tblinfo, int numTables
 			if (fout->remoteVersion < 180000 && foundNotNull)
 				tbinfo->notnull_islocal[j] = false;
 
+			/*
+			 * For versions >18, we must print the not-null constraint locally
+			 * for this table even if it isn't really locally defined, but is
+			 * valid for the child and no parent has it as valid.
+			 */
+			if (fout->remoteVersion >= 180000 && allNotNullsInvalid)
+				tbinfo->notnull_islocal[j] = true;
+
 			/*
 			 * Manufacture a DEFAULT NULL clause if necessary.  This breaks
 			 * the advice given above to avoid changing state that might get

src/bin/pg_dump/pg_dump.c

@@ -9099,8 +9099,8 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 	 *
 	 * We track in notnull_islocal whether the constraint was defined directly
 	 * in this table or via an ancestor, for binary upgrade.  flagInhAttrs
-	 * might modify this later for servers older than 18; it's also in charge
-	 * of determining the correct inhcount.
+	 * might modify this later; that routine is also in charge of determining
+	 * the correct inhcount.
 	 */
 	if (fout->remoteVersion >= 180000)
 		appendPQExpBufferStr(q,
@@ -9255,6 +9255,7 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
 		tbinfo->attfdwoptions = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->attmissingval = (char **) pg_malloc(numatts * sizeof(char *));
 		tbinfo->notnull_constrs = (char **) pg_malloc(numatts * sizeof(char *));
+		tbinfo->notnull_invalid = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_noinh = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->notnull_islocal = (bool *) pg_malloc(numatts * sizeof(bool));
 		tbinfo->attrdefs = (AttrDefInfo **) pg_malloc(numatts * sizeof(AttrDefInfo *));
@@ -9708,8 +9709,10 @@ getTableAttrs(Archive *fout, TableInfo *tblinfo, int numTables)
  * constraints and the columns in the child don't have their own NOT NULL
  * declarations, we suppress printing constraints in the child: the
  * constraints are acquired at the point where the child is attached to the
- * parent.  This is tracked in ->notnull_islocal (which is set in flagInhAttrs
- * for servers pre-18).
+ * parent.  This is tracked in ->notnull_islocal; for servers pre-18 this is
+ * set not here but in flagInhAttrs.  That flag is also used when the
+ * constraint was validated in a child but all its parent have it as NOT
+ * VALID.
  *
  * Any of these constraints might have the NO INHERIT bit.  If so we set
  * ->notnull_noinh and NO INHERIT will be printed by dumpTableSchema.
@@ -9756,6 +9759,12 @@ determineNotNullFlags(Archive *fout, PGresult *res, int r,
 		else
 			appendPQExpBuffer(*invalidnotnulloids, ",%s", constroid);
 
+		/*
+		 * Track when a parent constraint is invalid for the cases where a
+		 * child constraint has been validated independenly.
+		 */
+		tbinfo->notnull_invalid[j] = true;
+
 		/* nothing else to do */
 		tbinfo->notnull_constrs[j] = NULL;
 		return;
@@ -9763,10 +9772,11 @@ determineNotNullFlags(Archive *fout, PGresult *res, int r,
 
 	/*
 	 * notnull_noinh is straight from the query result. notnull_islocal also,
-	 * though flagInhAttrs may change that one later in versions < 18.
+	 * though flagInhAttrs may change that one later.
 	 */
 	tbinfo->notnull_noinh[j] = PQgetvalue(res, r, i_notnull_noinherit)[0] == 't';
 	tbinfo->notnull_islocal[j] = PQgetvalue(res, r, i_notnull_islocal)[0] == 't';
+	tbinfo->notnull_invalid[j] = false;
 
 	/*
 	 * Determine a constraint name to use.  If the column is not marked not-

src/bin/pg_dump/pg_dump.h

@@ -365,6 +365,7 @@ typedef struct _tableInfo
 									 * there isn't one on this column. If
 									 * empty string, unnamed constraint
 									 * (pre-v17) */
+	bool	   *notnull_invalid;	/* true for NOT NULL NOT VALID */
 	bool	   *notnull_noinh;	/* NOT NULL is NO INHERIT */
 	bool	   *notnull_islocal;	/* true if NOT NULL has local definition */
 	struct _attrDefInfo **attrdefs; /* DEFAULT expressions */

src/bin/pg_dump/t/002_pg_dump.pl

@@ -1118,10 +1118,21 @@ my %tests = (
 		},
 	},
 
-	'CONSTRAINT NOT NULL / INVALID' => {
+	'CONSTRAINT NOT NULL / NOT VALID' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_nn (
 							col1 int);
-			ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;',
+							CREATE TABLE dump_test.test_table_nn_2 (
+							col1 int NOT NULL);
+							CREATE TABLE dump_test.test_table_nn_chld1 (
+							) INHERITS (dump_test.test_table_nn);
+							CREATE TABLE dump_test.test_table_nn_chld2 (
+								col1 int
+							) INHERITS (dump_test.test_table_nn);
+							CREATE TABLE dump_test.test_table_nn_chld3 (
+							) INHERITS (dump_test.test_table_nn, dump_test.test_table_nn_2);
+			ALTER TABLE dump_test.test_table_nn ADD CONSTRAINT nn NOT NULL col1 NOT VALID;
+			ALTER TABLE dump_test.test_table_nn_chld1 VALIDATE CONSTRAINT nn;
+			ALTER TABLE dump_test.test_table_nn_chld2 VALIDATE CONSTRAINT nn;',
 		regexp => qr/^
 			\QALTER TABLE dump_test.test_table_nn\E \n^\s+
 			\QADD CONSTRAINT nn NOT NULL col1 NOT VALID;\E
@@ -1135,6 +1146,50 @@ my %tests = (
 		},
 	},
 
+	'CONSTRAINT NOT NULL / NOT VALID (child1)' => {
+		regexp => qr/^
+		\QCREATE TABLE dump_test.test_table_nn_chld1 (\E\n
+		^\s+\QCONSTRAINT nn NOT NULL col1\E$
+		/xm,
+		like => {
+			%full_runs, %dump_test_schema_runs, section_pre_data => 1,
+		},
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+			binary_upgrade => 1,
+		},
+	},
+
+	'CONSTRAINT NOT NULL / NOT VALID (child2)' => {
+		regexp => qr/^
+		\QCREATE TABLE dump_test.test_table_nn_chld2 (\E\n
+		^\s+\Qcol1 integer CONSTRAINT nn NOT NULL\E$
+		/xm,
+		like => {
+			%full_runs, %dump_test_schema_runs, section_pre_data => 1,
+		},
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
+	'CONSTRAINT NOT NULL / NOT VALID (child3)' => {
+		regexp => qr/^
+		\QCREATE TABLE dump_test.test_table_nn_chld3 (\E\n
+		^\Q)\E$
+		/xm,
+		like => {
+			%full_runs, %dump_test_schema_runs, section_pre_data => 1,
+		},
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+			binary_upgrade => 1,
+		},
+	},
+
 	'CONSTRAINT PRIMARY KEY / WITHOUT OVERLAPS' => {
 		create_sql => 'CREATE TABLE dump_test.test_table_tpk (
 							col1 int4range,

src/test/regress/expected/constraints.out

@@ -1625,6 +1625,40 @@ EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_
  notnull_part1_upg   | notnull_con | f            | t          |           0
 (4 rows)
 
+-- Inheritance test tables for pg_upgrade
+create table constr_parent (a int);
+create table constr_child (a int) inherits (constr_parent);
+NOTICE:  merging column "a" with inherited definition
+alter table constr_parent add not null a not valid;
+alter table constr_child validate constraint constr_parent_a_not_null;
+EXECUTE get_nnconstraint_info('{constr_parent, constr_child}');
+    tabname    |         conname          | convalidated | conislocal | coninhcount 
+---------------+--------------------------+--------------+------------+-------------
+ constr_child  | constr_parent_a_not_null | t            | f          |           1
+ constr_parent | constr_parent_a_not_null | f            | t          |           0
+(2 rows)
+
+create table constr_parent2 (a int);
+create table constr_child2 () inherits (constr_parent2);
+alter table constr_parent2 add not null a not valid;
+alter table constr_child2 validate constraint constr_parent2_a_not_null;
+EXECUTE get_nnconstraint_info('{constr_parent2, constr_child2}');
+    tabname     |          conname          | convalidated | conislocal | coninhcount 
+----------------+---------------------------+--------------+------------+-------------
+ constr_child2  | constr_parent2_a_not_null | t            | f          |           1
+ constr_parent2 | constr_parent2_a_not_null | f            | t          |           0
+(2 rows)
+
+create table constr_parent3 (a int not null);
+create table constr_child3 () inherits (constr_parent2, constr_parent3);
+NOTICE:  merging multiple inherited definitions of column "a"
+EXECUTE get_nnconstraint_info('{constr_parent3, constr_child3}');
+    tabname     |          conname          | convalidated | conislocal | coninhcount 
+----------------+---------------------------+--------------+------------+-------------
+ constr_child3  | constr_parent2_a_not_null | t            | f          |           2
+ constr_parent3 | constr_parent3_a_not_null | t            | t          |           0
+(2 rows)
+
 DEALLOCATE get_nnconstraint_info;
 -- end NOT NULL NOT VALID
 -- Comments

src/test/regress/sql/constraints.sql

@@ -979,6 +979,24 @@ INSERT INTO notnull_part1_3_upg values(NULL,1);
 ALTER TABLE notnull_part1_3_upg add CONSTRAINT nn3 NOT NULL a NOT VALID;
 ALTER TABLE notnull_part1_upg ATTACH PARTITION notnull_part1_3_upg FOR VALUES IN (NULL,5);
 EXECUTE get_nnconstraint_info('{notnull_part1_upg, notnull_part1_1_upg, notnull_part1_2_upg, notnull_part1_3_upg}');
+
+-- Inheritance test tables for pg_upgrade
+create table constr_parent (a int);
+create table constr_child (a int) inherits (constr_parent);
+alter table constr_parent add not null a not valid;
+alter table constr_child validate constraint constr_parent_a_not_null;
+EXECUTE get_nnconstraint_info('{constr_parent, constr_child}');
+
+create table constr_parent2 (a int);
+create table constr_child2 () inherits (constr_parent2);
+alter table constr_parent2 add not null a not valid;
+alter table constr_child2 validate constraint constr_parent2_a_not_null;
+EXECUTE get_nnconstraint_info('{constr_parent2, constr_child2}');
+
+create table constr_parent3 (a int not null);
+create table constr_child3 () inherits (constr_parent2, constr_parent3);
+EXECUTE get_nnconstraint_info('{constr_parent3, constr_child3}');
+
 DEALLOCATE get_nnconstraint_info;
 
 -- end NOT NULL NOT VALID