fix: scope pg_class joins by relnamespace to prevent cross-schema comment misattribution (#318)

cmd/dump/dump_integration_test.go

@@ -116,6 +116,74 @@ func TestDumpCommand_Issue307ViewDependencyOrder(t *testing.T) {
 	runExactMatchTest(t, "issue_307_view_dependency_order")
 }
 
+func TestDumpCommand_Issue318CrossSchemaComment(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping integration test in short mode")
+	}
+
+	// Setup PostgreSQL
+	embeddedPG := testutil.SetupPostgres(t)
+	defer embeddedPG.Stop()
+
+	// Connect to database
+	conn, host, port, dbname, user, password := testutil.ConnectToPostgres(t, embeddedPG)
+	defer conn.Close()
+
+	// Read and execute the setup SQL that creates two schemas with same-named tables
+	setupPath := "../../testdata/dump/issue_318_cross_schema_comment/setup.sql"
+	setupContent, err := os.ReadFile(setupPath)
+	if err != nil {
+		t.Fatalf("Failed to read %s: %v", setupPath, err)
+	}
+
+	_, err = conn.ExecContext(context.Background(), string(setupContent))
+	if err != nil {
+		t.Fatalf("Failed to execute setup.sql: %v", err)
+	}
+
+	// Dump each schema and verify comments are correctly attributed
+	tests := []struct {
+		schema       string
+		tableComment string
+		colComment   string
+	}{
+		{"alpha", "Alpha account table", "Alpha account name"},
+		{"beta", "Beta account table", "Beta account name"},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.schema, func(t *testing.T) {
+			config := &DumpConfig{
+				Host:      host,
+				Port:      port,
+				DB:        dbname,
+				User:      user,
+				Password:  password,
+				Schema:    tc.schema,
+				MultiFile: false,
+				File:      "",
+			}
+
+			output, err := ExecuteDump(config)
+			if err != nil {
+				t.Fatalf("Dump command failed for schema %s: %v", tc.schema, err)
+			}
+
+			// Verify table comment
+			expectedTableComment := fmt.Sprintf("COMMENT ON TABLE account IS '%s';", tc.tableComment)
+			if !strings.Contains(output, expectedTableComment) {
+				t.Errorf("Schema %s: expected table comment %q not found in output:\n%s", tc.schema, expectedTableComment, output)
+			}
+
+			// Verify column comment
+			expectedColComment := fmt.Sprintf("COMMENT ON COLUMN account.name IS '%s';", tc.colComment)
+			if !strings.Contains(output, expectedColComment) {
+				t.Errorf("Schema %s: expected column comment %q not found in output:\n%s", tc.schema, expectedColComment, output)
+			}
+		})
+	}
+}
+
 func TestDumpCommand_Issue307MultiFileViewDependencyOrder(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping integration test in short mode")

ir/queries/queries.sql

@@ -28,10 +28,10 @@ SELECT
     t.table_type,
     COALESCE(d.description, '') AS table_comment
 FROM information_schema.tables t
-LEFT JOIN pg_class c ON c.relname = t.table_name
-LEFT JOIN pg_namespace n ON c.relnamespace = n.oid AND n.nspname = t.table_schema
+LEFT JOIN pg_namespace n ON n.nspname = t.table_schema
+LEFT JOIN pg_class c ON c.relname = t.table_name AND c.relnamespace = n.oid
 LEFT JOIN pg_description d ON d.objoid = c.oid AND d.classoid = 'pg_class'::regclass AND d.objsubid = 0
-WHERE 
+WHERE
     t.table_schema NOT IN ('information_schema', 'pg_catalog', 'pg_toast')
     AND t.table_schema NOT LIKE 'pg_temp_%'
     AND t.table_schema NOT LIKE 'pg_toast_temp_%'
@@ -40,16 +40,16 @@ ORDER BY t.table_schema, t.table_name;
 
 -- GetTablesForSchema retrieves all tables in a specific schema with metadata
 -- name: GetTablesForSchema :many
-SELECT 
+SELECT
     t.table_schema,
     t.table_name,
     t.table_type,
     COALESCE(d.description, '') AS table_comment
 FROM information_schema.tables t
-LEFT JOIN pg_class c ON c.relname = t.table_name
-LEFT JOIN pg_namespace n ON c.relnamespace = n.oid AND n.nspname = t.table_schema
+LEFT JOIN pg_namespace n ON n.nspname = t.table_schema
+LEFT JOIN pg_class c ON c.relname = t.table_name AND c.relnamespace = n.oid
 LEFT JOIN pg_description d ON d.objoid = c.oid AND d.classoid = 'pg_class'::regclass AND d.objsubid = 0
-WHERE 
+WHERE
     t.table_schema = $1
     AND t.table_type IN ('BASE TABLE', 'VIEW')
 ORDER BY t.table_name;
@@ -109,8 +109,8 @@ WITH column_base AS (
         ad.adbin,
         ad.adrelid
     FROM information_schema.columns c
-    LEFT JOIN pg_class cl ON cl.relname = c.table_name
-    LEFT JOIN pg_namespace n ON cl.relnamespace = n.oid AND n.nspname = c.table_schema
+    LEFT JOIN pg_namespace n ON n.nspname = c.table_schema
+    LEFT JOIN pg_class cl ON cl.relname = c.table_name AND cl.relnamespace = n.oid
     LEFT JOIN pg_description d ON d.objoid = cl.oid AND d.classoid = 'pg_class'::regclass AND d.objsubid = c.ordinal_position
     LEFT JOIN pg_attribute a ON a.attrelid = cl.oid AND a.attname = c.column_name
     LEFT JOIN pg_attrdef ad ON ad.adrelid = a.attrelid AND ad.adnum = a.attnum
@@ -939,8 +939,8 @@ SELECT
     COALESCE(dep_table.relname, col_table.table_name) AS owned_by_table,
     COALESCE(dep_col.attname, col_table.column_name) AS owned_by_column
 FROM pg_sequences s
-LEFT JOIN pg_class c ON c.relname = s.sequencename
-LEFT JOIN pg_namespace n ON c.relnamespace = n.oid AND n.nspname = s.schemaname
+LEFT JOIN pg_namespace n ON n.nspname = s.schemaname
+LEFT JOIN pg_class c ON c.relname = s.sequencename AND c.relnamespace = n.oid
 -- Method 1: Try to find dependency relationship (for proper SERIAL columns)
 LEFT JOIN pg_depend d ON d.objid = c.oid AND d.classid = 'pg_class'::regclass AND d.deptype IN ('a', 'i')
 LEFT JOIN pg_class dep_table ON d.refobjid = dep_table.oid

testdata/dump/issue_318_cross_schema_comment/manifest.json

@@ -0,0 +1,9 @@
+{
+  "name": "issue_318_cross_schema_comment",
+  "description": "Test case for wrong table/column comments when same table name exists in multiple schemas (GitHub issue #318)",
+  "source": "https://github.com/pgplex/pgschema/issues/318",
+  "notes": [
+    "Reproduces the bug where pg_class join on relname alone (without relnamespace) causes wrong comment attribution",
+    "Tests that table and column comments are correctly scoped to their own schema when dumping"
+  ]
+}

testdata/dump/issue_318_cross_schema_comment/setup.sql

@@ -0,0 +1,24 @@
+--
+-- Setup: Two schemas with identically-named tables but different comments.
+-- This reproduces GitHub issue #318 where the buggy pg_class join on relname
+-- alone (without relnamespace) can cause wrong comment attribution.
+--
+
+CREATE SCHEMA alpha;
+CREATE SCHEMA beta;
+
+CREATE TABLE alpha.account (
+    id serial PRIMARY KEY,
+    name text NOT NULL
+);
+
+COMMENT ON TABLE alpha.account IS 'Alpha account table';
+COMMENT ON COLUMN alpha.account.name IS 'Alpha account name';
+
+CREATE TABLE beta.account (
+    id serial PRIMARY KEY,
+    name text NOT NULL
+);
+
+COMMENT ON TABLE beta.account IS 'Beta account table';
+COMMENT ON COLUMN beta.account.name IS 'Beta account name';