fix: table-level CHECK constraints with IS NOT NULL silently omitted from dump (#396) (#398)

The inspector was using strings.Contains(checkClause, "IS NOT NULL") to skip
system-generated NOT NULL constraints, but this incorrectly filtered out any
CHECK constraint whose expression contained IS NOT NULL — including complex
user-defined constraints like CHECK (status = 'active' OR reason IS NOT NULL).

Narrowed the filter to only skip simple single-identifier NOT NULL checks
(e.g., CHECK ((value IS NOT NULL))) by stripping the CHECK wrapper and
parentheses and verifying the prefix is a single word with no spaces.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: tianzhou

cmd/dump/dump_integration_test.go

@@ -130,6 +130,13 @@ func TestDumpCommand_Issue345ArrayCast(t *testing.T) {
 	runExactMatchTest(t, "issue_345_array_cast")
 }
 
+func TestDumpCommand_Issue396CheckConstraintIsNotNull(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping integration test in short mode")
+	}
+	runExactMatchTest(t, "issue_396_check_constraint_is_not_null")
+}
+
 func TestDumpCommand_Issue191FunctionProcedureOverload(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping integration test in short mode")

ir/inspector.go

@@ -517,9 +517,18 @@ func (i *Inspector) buildConstraints(ctx context.Context, schema *IR, targetSche
 			// Handle check constraints
 			if cType == ConstraintTypeCheck {
 				if checkClause := i.safeInterfaceToString(constraint.CheckClause); checkClause != "" && checkClause != "<nil>" {
-					// Skip system-generated NOT NULL constraints as they're redundant with column definitions
-					if strings.Contains(checkClause, "IS NOT NULL") {
-						continue
+					// Skip simple NOT NULL check constraints (e.g., "CHECK ((value IS NOT NULL))")
+					// as they're redundant with column definitions. Only skip if the entire
+					// expression is just "identifier IS NOT NULL".
+					inner := strings.TrimPrefix(strings.TrimSpace(checkClause), "CHECK ")
+					inner = strings.TrimSpace(inner)
+					for len(inner) > 2 && inner[0] == '(' && inner[len(inner)-1] == ')' && isBalancedParentheses(inner[1:len(inner)-1]) {
+						inner = strings.TrimSpace(inner[1 : len(inner)-1])
+					}
+					if prefix, ok := strings.CutSuffix(inner, " IS NOT NULL"); ok {
+						if !strings.Contains(strings.TrimSpace(prefix), " ") {
+							continue
+						}
 					}
 
 					// Use CheckClause as-is from PostgreSQL's pg_get_constraintdef(c.oid, true)

testdata/dump/issue_396_check_constraint_is_not_null/manifest.json

@@ -0,0 +1,9 @@
+{
+  "name": "issue_396_check_constraint_is_not_null",
+  "description": "Table-level CHECK constraints containing IS NOT NULL in complex expressions are silently omitted from schema dump",
+  "source": "https://github.com/pgplex/pgschema/issues/396",
+  "notes": [
+    "The inspector incorrectly skips CHECK constraints that contain 'IS NOT NULL' anywhere in the expression",
+    "Only simple NOT NULL check constraints should be skipped, not complex expressions using IS NOT NULL"
+  ]
+}

testdata/dump/issue_396_check_constraint_is_not_null/pgdump.sql

@@ -0,0 +1,40 @@
+--
+-- PostgreSQL database dump
+--
+
+SET statement_timeout = 0;
+SET lock_timeout = 0;
+SET client_encoding = 'UTF8';
+SET standard_conforming_strings = on;
+SET check_function_bodies = false;
+SET client_min_messages = warning;
+SET row_security = off;
+
+--
+-- Name: test_table; Type: TABLE; Schema: public; Owner: -
+--
+
+CREATE TABLE public.test_table (
+    id integer NOT NULL,
+    status text NOT NULL,
+    reason text,
+    actor_id uuid
+);
+
+--
+-- Name: test_table test_table_pkey; Type: CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.test_table
+    ADD CONSTRAINT test_table_pkey PRIMARY KEY (id);
+
+--
+-- Name: test_table test_table_status_check; Type: CHECK CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE public.test_table
+    ADD CONSTRAINT test_table_status_check CHECK (((status = 'active'::text) OR ((status = 'cancelled'::text) AND (reason IS NOT NULL)) OR ((status = 'revoked'::text) AND (actor_id IS NOT NULL))));
+
+--
+-- PostgreSQL database dump complete
+--

testdata/dump/issue_396_check_constraint_is_not_null/pgschema.sql

@@ -0,0 +1,21 @@
+--
+-- pgschema database dump
+--
+
+-- Dumped from database version PostgreSQL 18.0
+-- Dumped by pgschema version 1.9.0
+
+
+--
+-- Name: test_table; Type: TABLE; Schema: -; Owner: -
+--
+
+CREATE TABLE IF NOT EXISTS test_table (
+    id integer,
+    status text NOT NULL,
+    reason text,
+    actor_id uuid,
+    CONSTRAINT test_table_pkey PRIMARY KEY (id),
+    CONSTRAINT test_table_status_check CHECK (status = 'active'::text OR status = 'cancelled'::text AND reason IS NOT NULL OR status = 'revoked'::text AND actor_id IS NOT NULL)
+);
+

testdata/dump/issue_396_check_constraint_is_not_null/raw.sql

@@ -0,0 +1,19 @@
+--
+-- Test case for GitHub issue #396: Table-level CHECK constraints omitted from schema dump
+--
+-- CHECK constraints containing IS NOT NULL in complex expressions
+-- are silently dropped because the inspector filters out any constraint
+-- with "IS NOT NULL" in its expression, not just simple NOT NULL constraints.
+--
+
+CREATE TABLE test_table (
+    id int PRIMARY KEY,
+    status text NOT NULL,
+    reason text,
+    actor_id uuid,
+    CONSTRAINT test_table_status_check CHECK (
+        (status = 'active')
+        OR (status = 'cancelled' AND reason IS NOT NULL)
+        OR (status = 'revoked' AND actor_id IS NOT NULL)
+    )
+);