pg_dump: include comments on not-null constraints on domains, too

Commit e5da0fe3c2 introduced catalog entries for not-null constraints
on domains; but because commit b0e96f3119 (the original work for
catalogued not-null constraints on tables) forgot to teach pg_dump to
process the comments for them, this one also forgot.  Add that now.

We also need to teach repairDependencyLoop() about the new type of
constraints being possible for domains.

Backpatch-through: 17
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>
Discussion: https://postgr.es/m/CACJufxF-0bqVR=j4jonS6N2Ka6hHUpFyu3_3TWKNhOW_4yFSSg@mail.gmail.com

src/bin/pg_dump/pg_dump.c

@@ -47,6 +47,7 @@
 #include "catalog/pg_authid_d.h"
 #include "catalog/pg_cast_d.h"
 #include "catalog/pg_class_d.h"
+#include "catalog/pg_constraint_d.h"
 #include "catalog/pg_default_acl_d.h"
 #include "catalog/pg_largeobject_d.h"
 #include "catalog/pg_largeobject_metadata_d.h"
@@ -5929,6 +5930,7 @@ getTypes(Archive *fout, int *numTypes)
 		 */
 		tyinfo[i].nDomChecks = 0;
 		tyinfo[i].domChecks = NULL;
+		tyinfo[i].notnull = NULL;
 		if ((tyinfo[i].dobj.dump & DUMP_COMPONENT_DEFINITION) &&
 			tyinfo[i].typtype == TYPTYPE_DOMAIN)
 			getDomainConstraints(fout, &(tyinfo[i]));
@@ -7949,27 +7951,33 @@ addConstrChildIdxDeps(DumpableObject *dobj, const IndxInfo *refidx)
 static void
 getDomainConstraints(Archive *fout, TypeInfo *tyinfo)
 {
-	int			i;
 	ConstraintInfo *constrinfo;
 	PQExpBuffer query = createPQExpBuffer();
 	PGresult   *res;
 	int			i_tableoid,
 				i_oid,
 				i_conname,
-				i_consrc;
+				i_consrc,
+				i_convalidated,
+				i_contype;
 	int			ntups;
 
 	if (!fout->is_prepared[PREPQUERY_GETDOMAINCONSTRAINTS])
 	{
-		/* Set up query for constraint-specific details */
+		/*
-		appendPQExpBufferStr(query,
+		 * Set up query for constraint-specific details.  For servers 17 and
-							 "PREPARE getDomainConstraints(pg_catalog.oid) AS\n"
+		 * up, domains have constraints of type 'n' as well as 'c', otherwise
-							 "SELECT tableoid, oid, conname, "
+		 * just the latter.
-							 "pg_catalog.pg_get_constraintdef(oid) AS consrc, "
+		 */
-							 "convalidated "
+		appendPQExpBuffer(query,
-							 "FROM pg_catalog.pg_constraint "
+						  "PREPARE getDomainConstraints(pg_catalog.oid) AS\n"
-							 "WHERE contypid = $1 AND contype = 'c' "
+						  "SELECT tableoid, oid, conname, "
-							 "ORDER BY conname");
+						  "pg_catalog.pg_get_constraintdef(oid) AS consrc, "
+						  "convalidated, contype "
+						  "FROM pg_catalog.pg_constraint "
+						  "WHERE contypid = $1 AND contype IN (%s) "
+						  "ORDER BY conname",
+						  fout->remoteVersion < 170000 ? "'c'" : "'c', 'n'");
 
 		ExecuteSqlStatement(fout, query->data);
 
@@ -7988,33 +7996,50 @@ getDomainConstraints(Archive *fout, TypeInfo *tyinfo)
 	i_oid = PQfnumber(res, "oid");
 	i_conname = PQfnumber(res, "conname");
 	i_consrc = PQfnumber(res, "consrc");
+	i_convalidated = PQfnumber(res, "convalidated");
+	i_contype = PQfnumber(res, "contype");
 
 	constrinfo = (ConstraintInfo *) pg_malloc(ntups * sizeof(ConstraintInfo));
-
-	tyinfo->nDomChecks = ntups;
 	tyinfo->domChecks = constrinfo;
 
-	for (i = 0; i < ntups; i++)
+	/* 'i' tracks result rows; 'j' counts CHECK constraints */
+	for (int i = 0, j = 0; i < ntups; i++)
 	{
-		bool		validated = PQgetvalue(res, i, 4)[0] == 't';
+		bool		validated = PQgetvalue(res, i, i_convalidated)[0] == 't';
+		char		contype = (PQgetvalue(res, i, i_contype))[0];
+		ConstraintInfo *constraint;
 
-		constrinfo[i].dobj.objType = DO_CONSTRAINT;
+		if (contype == CONSTRAINT_CHECK)
-		constrinfo[i].dobj.catId.tableoid = atooid(PQgetvalue(res, i, i_tableoid));
+		{
-		constrinfo[i].dobj.catId.oid = atooid(PQgetvalue(res, i, i_oid));
+			constraint = &constrinfo[j++];
-		AssignDumpId(&constrinfo[i].dobj);
+			tyinfo->nDomChecks++;
-		constrinfo[i].dobj.name = pg_strdup(PQgetvalue(res, i, i_conname));
+		}
-		constrinfo[i].dobj.namespace = tyinfo->dobj.namespace;
+		else
-		constrinfo[i].contable = NULL;
+		{
-		constrinfo[i].condomain = tyinfo;
+			Assert(contype == CONSTRAINT_NOTNULL);
-		constrinfo[i].contype = 'c';
+			Assert(tyinfo->notnull == NULL);
-		constrinfo[i].condef = pg_strdup(PQgetvalue(res, i, i_consrc));
+			/* use last item in array for the not-null constraint */
-		constrinfo[i].confrelid = InvalidOid;
+			tyinfo->notnull = &(constrinfo[ntups - 1]);
-		constrinfo[i].conindex = 0;
+			constraint = tyinfo->notnull;
-		constrinfo[i].condeferrable = false;
+		}
-		constrinfo[i].condeferred = false;
-		constrinfo[i].conislocal = true;
 
-		constrinfo[i].separate = !validated;
+		constraint->dobj.objType = DO_CONSTRAINT;
+		constraint->dobj.catId.tableoid = atooid(PQgetvalue(res, i, i_tableoid));
+		constraint->dobj.catId.oid = atooid(PQgetvalue(res, i, i_oid));
+		AssignDumpId(&(constraint->dobj));
+		constraint->dobj.name = pg_strdup(PQgetvalue(res, i, i_conname));
+		constraint->dobj.namespace = tyinfo->dobj.namespace;
+		constraint->contable = NULL;
+		constraint->condomain = tyinfo;
+		constraint->contype = contype;
+		constraint->condef = pg_strdup(PQgetvalue(res, i, i_consrc));
+		constraint->confrelid = InvalidOid;
+		constraint->conindex = 0;
+		constraint->condeferrable = false;
+		constraint->condeferred = false;
+		constraint->conislocal = true;
+
+		constraint->separate = !validated;
 
 		/*
 		 * Make the domain depend on the constraint, ensuring it won't be
@@ -8023,8 +8048,7 @@ getDomainConstraints(Archive *fout, TypeInfo *tyinfo)
 		 * anyway, so this doesn't matter.
 		 */
 		if (validated)
-			addObjectDependency(&tyinfo->dobj,
+			addObjectDependency(&tyinfo->dobj, constraint->dobj.dumpId);
-								constrinfo[i].dobj.dumpId);
 	}
 
 	PQclear(res);
@@ -11557,8 +11581,36 @@ dumpDomain(Archive *fout, const TypeInfo *tyinfo)
 			appendPQExpBuffer(q, " COLLATE %s", fmtQualifiedDumpable(coll));
 	}
 
+	/*
+	 * Print a not-null constraint if there's one.  In servers older than 17
+	 * these don't have names, so just print it unadorned; in newer ones they
+	 * do, but most of the time it's going to be the standard generated one,
+	 * so omit the name in that case also.
+	 */
 	if (typnotnull[0] == 't')
-		appendPQExpBufferStr(q, " NOT NULL");
+	{
+		if (fout->remoteVersion < 170000 || tyinfo->notnull == NULL)
+			appendPQExpBufferStr(q, " NOT NULL");
+		else
+		{
+			ConstraintInfo *notnull = tyinfo->notnull;
+
+			if (!notnull->separate)
+			{
+				char	   *default_name;
+
+				/* XXX should match ChooseConstraintName better */
+				default_name = psprintf("%s_not_null", tyinfo->dobj.name);
+
+				if (strcmp(default_name, notnull->dobj.name) == 0)
+					appendPQExpBufferStr(q, " NOT NULL");
+				else
+					appendPQExpBuffer(q, " CONSTRAINT %s %s",
+									  fmtId(notnull->dobj.name), notnull->condef);
+				free(default_name);
+			}
+		}
+	}
 
 	if (typdefault != NULL)
 	{
@@ -11578,7 +11630,7 @@ dumpDomain(Archive *fout, const TypeInfo *tyinfo)
 	{
 		ConstraintInfo *domcheck = &(tyinfo->domChecks[i]);
 
-		if (!domcheck->separate)
+		if (!domcheck->separate && domcheck->contype == 'c')
 			appendPQExpBuffer(q, "\n\tCONSTRAINT %s %s",
 							  fmtId(domcheck->dobj.name), domcheck->condef);
 	}
@@ -11642,6 +11694,25 @@ dumpDomain(Archive *fout, const TypeInfo *tyinfo)
 		destroyPQExpBuffer(conprefix);
 	}
 
+	/*
+	 * And a comment on the not-null constraint, if there's one -- but only if
+	 * the constraint itself was dumped here
+	 */
+	if (tyinfo->notnull != NULL && !tyinfo->notnull->separate)
+	{
+		PQExpBuffer conprefix = createPQExpBuffer();
+
+		appendPQExpBuffer(conprefix, "CONSTRAINT %s ON DOMAIN",
+						  fmtId(tyinfo->notnull->dobj.name));
+
+		if (tyinfo->notnull->dobj.dump & DUMP_COMPONENT_COMMENT)
+			dumpComment(fout, conprefix->data, qtypname,
+						tyinfo->dobj.namespace->dobj.name,
+						tyinfo->rolname,
+						tyinfo->notnull->dobj.catId, 0, tyinfo->dobj.dumpId);
+		destroyPQExpBuffer(conprefix);
+	}
+
 	destroyPQExpBuffer(q);
 	destroyPQExpBuffer(delq);
 	destroyPQExpBuffer(query);
@@ -17336,14 +17407,23 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 										  .dropStmt = delq->data));
 		}
 	}
-	else if (coninfo->contype == 'c' && tbinfo == NULL)
+	else if (tbinfo == NULL)
 	{
-		/* CHECK constraint on a domain */
+		/* CHECK, NOT NULL constraint on a domain */
 		TypeInfo   *tyinfo = coninfo->condomain;
 
+		Assert(coninfo->contype == 'c' || coninfo->contype == 'n');
+
 		/* Ignore if not to be dumped separately */
 		if (coninfo->separate)
 		{
+			const char *keyword;
+
+			if (coninfo->contype == 'c')
+				keyword = "CHECK CONSTRAINT";
+			else
+				keyword = "CONSTRAINT";
+
 			appendPQExpBuffer(q, "ALTER DOMAIN %s\n",
 							  fmtQualifiedDumpable(tyinfo));
 			appendPQExpBuffer(q, "    ADD CONSTRAINT %s %s;\n",
@@ -17362,7 +17442,7 @@ dumpConstraint(Archive *fout, const ConstraintInfo *coninfo)
 							 ARCHIVE_OPTS(.tag = tag,
 										  .namespace = tyinfo->dobj.namespace->dobj.name,
 										  .owner = tyinfo->rolname,
-										  .description = "CHECK CONSTRAINT",
+										  .description = keyword,
 										  .section = SECTION_POST_DATA,
 										  .createStmt = q->data,
 										  .dropStmt = delq->data));

src/bin/pg_dump/pg_dump.h

@@ -215,7 +215,9 @@ typedef struct _typeInfo
 	bool		isDefined;		/* true if typisdefined */
 	/* If needed, we'll create a "shell type" entry for it; link that here: */
 	struct _shellTypeInfo *shellType;	/* shell-type entry, or NULL */
-	/* If it's a domain, we store links to its constraints here: */
+	/* If it's a domain, its not-null constraint is here: */
+	struct _constraintInfo *notnull;
+	/* If it's a domain, we store links to its CHECK constraints here: */
 	int			nDomChecks;
 	struct _constraintInfo *domChecks;
 } TypeInfo;

src/bin/pg_dump/pg_dump_sort.c

@@ -884,7 +884,7 @@ repairTableAttrDefMultiLoop(DumpableObject *tableobj,
 }
 
 /*
- * CHECK constraints on domains work just like those on tables ...
+ * CHECK, NOT NULL constraints on domains work just like those on tables ...
  */
 static void
 repairDomainConstraintLoop(DumpableObject *domainobj,
@@ -1135,11 +1135,12 @@ repairDependencyLoop(DumpableObject **loop,
 		}
 	}
 
-	/* Domain and CHECK constraint */
+	/* Domain and CHECK or NOT NULL constraint */
 	if (nLoop == 2 &&
 		loop[0]->objType == DO_TYPE &&
 		loop[1]->objType == DO_CONSTRAINT &&
-		((ConstraintInfo *) loop[1])->contype == 'c' &&
+		(((ConstraintInfo *) loop[1])->contype == 'c' ||
+		 ((ConstraintInfo *) loop[1])->contype == 'n') &&
 		((ConstraintInfo *) loop[1])->condomain == (TypeInfo *) loop[0])
 	{
 		repairDomainConstraintLoop(loop[0], loop[1]);
@@ -1148,14 +1149,15 @@ repairDependencyLoop(DumpableObject **loop,
 	if (nLoop == 2 &&
 		loop[1]->objType == DO_TYPE &&
 		loop[0]->objType == DO_CONSTRAINT &&
-		((ConstraintInfo *) loop[0])->contype == 'c' &&
+		(((ConstraintInfo *) loop[0])->contype == 'c' ||
+		 ((ConstraintInfo *) loop[0])->contype == 'n') &&
 		((ConstraintInfo *) loop[0])->condomain == (TypeInfo *) loop[1])
 	{
 		repairDomainConstraintLoop(loop[1], loop[0]);
 		return;
 	}
 
-	/* Indirect loop involving domain and CHECK constraint */
+	/* Indirect loop involving domain and CHECK or NOT NULL constraint */
 	if (nLoop > 2)
 	{
 		for (i = 0; i < nLoop; i++)
@@ -1165,7 +1167,8 @@ repairDependencyLoop(DumpableObject **loop,
 				for (j = 0; j < nLoop; j++)
 				{
 					if (loop[j]->objType == DO_CONSTRAINT &&
-						((ConstraintInfo *) loop[j])->contype == 'c' &&
+						(((ConstraintInfo *) loop[j])->contype == 'c' ||
+						 ((ConstraintInfo *) loop[j])->contype == 'n') &&
 						((ConstraintInfo *) loop[j])->condomain == (TypeInfo *) loop[i])
 					{
 						repairDomainConstraintMultiLoop(loop[i], loop[j]);

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

@@ -2041,17 +2041,19 @@ my %tests = (
 		create_sql => 'CREATE DOMAIN dump_test.us_postal_code AS TEXT
 		               COLLATE "C"
 					   DEFAULT \'10014\'
+					   CONSTRAINT nn NOT NULL
 					   CHECK(VALUE ~ \'^\d{5}$\' OR
 							 VALUE ~ \'^\d{5}-\d{4}$\');
+					   COMMENT ON CONSTRAINT nn
+						 ON DOMAIN dump_test.us_postal_code IS \'not null\';
 					   COMMENT ON CONSTRAINT us_postal_code_check
 						 ON DOMAIN dump_test.us_postal_code IS \'check it\';',
 		regexp => qr/^
-			\QCREATE DOMAIN dump_test.us_postal_code AS text COLLATE pg_catalog."C" DEFAULT '10014'::text\E\n\s+
+			\QCREATE DOMAIN dump_test.us_postal_code AS text COLLATE pg_catalog."C" CONSTRAINT nn NOT NULL DEFAULT '10014'::text\E\n\s+
 			\QCONSTRAINT us_postal_code_check CHECK \E
 			\Q(((VALUE ~ '^\d{5}\E
 			\$\Q'::text) OR (VALUE ~ '^\d{5}-\d{4}\E\$
 			\Q'::text)));\E(.|\n)*
-			\QCOMMENT ON CONSTRAINT us_postal_code_check ON DOMAIN dump_test.us_postal_code IS 'check it';\E
 			/xm,
 		like =>
 		  { %full_runs, %dump_test_schema_runs, section_pre_data => 1, },
@@ -2061,6 +2063,30 @@ my %tests = (
 		},
 	},
 
+	'COMMENT ON CONSTRAINT ON DOMAIN (1)' => {
+		regexp => qr/^
+		\QCOMMENT ON CONSTRAINT nn ON DOMAIN dump_test.us_postal_code IS '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,
+		},
+	},
+
+	'COMMENT ON CONSTRAINT ON DOMAIN (2)' => {
+		regexp => qr/^
+		\QCOMMENT ON CONSTRAINT us_postal_code_check ON DOMAIN dump_test.us_postal_code IS 'check it';\E
+		/xm,
+		like =>
+		  { %full_runs, %dump_test_schema_runs, section_pre_data => 1, },
+		unlike => {
+			exclude_dump_test_schema => 1,
+			only_dump_measurement => 1,
+		},
+	},
+
 	'CREATE FUNCTION dump_test.pltestlang_call_handler' => {
 		create_order => 17,
 		create_sql => 'CREATE FUNCTION dump_test.pltestlang_call_handler()