Merge pull request #345 from constructive-io/fix/deparse-assign-named-args

fix(plpgsql-deparser): decide assignment targets by parse mode, not a ':=' substring test

Author: pyramation

__fixtures__/plpgsql-generated/generated.json

@@ -163,6 +163,8 @@
   "plpgsql_deparser_fixes-63.sql": "CREATE FUNCTION test_alias_positional_param(integer) RETURNS integer\nLANGUAGE plpgsql AS $$\nDECLARE\n  arg ALIAS FOR $1;\nBEGIN\n  RETURN arg + 1;\nEND$$",
   "plpgsql_deparser_fixes-64.sql": "CREATE FUNCTION test_alias_named(input_value text) RETURNS text\nLANGUAGE plpgsql AS $$\nDECLARE\n  val ALIAS FOR input_value;\n  buffer text := 'x';\n  buf ALIAS FOR buffer;\nBEGIN\n  buf := buf || val;\n  RETURN buf;\nEND$$",
   "plpgsql_deparser_fixes-65.sql": "CREATE FUNCTION test_alias_trigger() RETURNS trigger\nLANGUAGE plpgsql AS $$\nDECLARE\n  prior ALIAS FOR old;\n  updated ALIAS FOR new;\nBEGIN\n  updated.updated_at := now();\n  RETURN updated;\nEND$$",
+  "plpgsql_deparser_fixes-66.sql": "CREATE FUNCTION test_assign_named_args() RETURNS text\nLANGUAGE plpgsql AS $$\nDECLARE\n  v_body text;\nBEGIN\n  v_body := ast_helpers.create_function(v_schema_name := 'app_public', v_function_name := 'f');\n  RETURN v_body;\nEND$$",
+  "plpgsql_deparser_fixes-67.sql": "CREATE FUNCTION test_assign_targets() RETURNS void\nLANGUAGE plpgsql AS $$\nDECLARE\n  a int[] := ARRAY[1, 2];\n  r record;\nBEGIN\n  SELECT 1 AS f INTO r;\n  a[2] := coalesce(nullif(3, 0), 4);\n  r.f := greatest(1, 2);\nEND$$",
   "plpgsql_control-1.sql": "do $$\nbegin\n  -- basic case\n  for i in 1..3 loop\n    raise notice '1..3: i = %', i;\n  end loop;\n  -- with BY, end matches exactly\n  for i in 1..10 by 3 loop\n    raise notice '1..10 by 3: i = %', i;\n  end loop;\n  -- with BY, end does not match\n  for i in 1..11 by 3 loop\n    raise notice '1..11 by 3: i = %', i;\n  end loop;\n  -- zero iterations\n  for i in 1..0 by 3 loop\n    raise notice '1..0 by 3: i = %', i;\n  end loop;\n  -- REVERSE\n  for i in reverse 10..0 by 3 loop\n    raise notice 'reverse 10..0 by 3: i = %', i;\n  end loop;\n  -- potential overflow\n  for i in 2147483620..2147483647 by 10 loop\n    raise notice '2147483620..2147483647 by 10: i = %', i;\n  end loop;\n  -- potential overflow, reverse direction\n  for i in reverse -2147483620..-2147483647 by 10 loop\n    raise notice 'reverse -2147483620..-2147483647 by 10: i = %', i;\n  end loop;\nend$$",
   "plpgsql_control-2.sql": "do $$\nbegin\n  for i in 1..3 by 0 loop\n    raise notice '1..3 by 0: i = %', i;\n  end loop;\nend$$",
   "plpgsql_control-3.sql": "do $$\nbegin\n  for i in 1..3 by -1 loop\n    raise notice '1..3 by -1: i = %', i;\n  end loop;\nend$$",
@@ -207,24 +209,25 @@
   "plpgsql_call-23.sql": "DO $$\nDECLARE _a int; _b int;\nBEGIN\n  _a := 10; _b := 30;\n  CALL test_proc9(_a, _b);\n  RAISE NOTICE '_a: %, _b: %', _a, _b;\nEND\n$$",
   "plpgsql_call-24.sql": "CREATE PROCEDURE test_proc10(IN a int, OUT b int, IN c int DEFAULT 11)\nLANGUAGE plpgsql\nAS $$\nBEGIN\n  RAISE NOTICE 'a: %, b: %, c: %', a, b, c;\n  b := a - c;\nEND;\n$$",
   "plpgsql_call-25.sql": "DO $$\nDECLARE _a int; _b int; _c int;\nBEGIN\n  _a := 10; _b := 30; _c := 7;\n  CALL test_proc10(_a, _b, _c);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\n\n  _a := 10; _b := 30; _c := 7;\n  CALL test_proc10(_a, _b, c => _c);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\n\n  _a := 10; _b := 30; _c := 7;\n  CALL test_proc10(a => _a, b => _b, c => _c);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\n\n  _a := 10; _b := 30; _c := 7;\n  CALL test_proc10(_a, c => _c, b => _b);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\n\n  _a := 10; _b := 30; _c := 7;\n  CALL test_proc10(_a, _b);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\n\n  _a := 10; _b := 30; _c := 7;\n  CALL test_proc10(_a, b => _b);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\n\n  _a := 10; _b := 30; _c := 7;\n  CALL test_proc10(b => _b, a => _a);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\nEND\n$$",
-  "plpgsql_call-26.sql": "DO $$\nDECLARE _a int; _b int; _c int;\nBEGIN\n  _a := 10; _b := 30; _c := 7;\n  CALL test_proc11(_a, _b, _c);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\nEND\n$$",
-  "plpgsql_call-27.sql": "CREATE PROCEDURE test_proc12(a anyelement, OUT b anyelement, OUT c anyarray)\nLANGUAGE plpgsql\nAS $$\nBEGIN\n  RAISE NOTICE 'a: %', a;\n  b := a;\n  c := array[a];\nEND;\n$$",
-  "plpgsql_call-28.sql": "DO $$\nDECLARE _a int; _b int; _c int[];\nBEGIN\n  _a := 10;\n  CALL test_proc12(_a, _b, _c);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\nEND\n$$",
-  "plpgsql_call-29.sql": "DO $$\nDECLARE _a int; _b int; _c text[];\nBEGIN\n  _a := 10;\n  CALL test_proc12(_a, _b, _c);  -- error\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\nEND\n$$",
-  "plpgsql_call-30.sql": "CREATE FUNCTION triggerfunc1() RETURNS trigger\nLANGUAGE plpgsql\nAS $$\nDECLARE\n    z int := 0;\nBEGIN\n    CALL test_proc6(2, NEW.a, NEW.a);\n    RETURN NEW;\nEND;\n$$",
-  "plpgsql_call-31.sql": "CREATE PROCEDURE p1(v_cnt int, v_Text inout text = NULL)\nAS $$\nBEGIN\n  v_Text := 'v_cnt = ' || v_cnt;\nEND\n$$ LANGUAGE plpgsql",
-  "plpgsql_call-32.sql": "DO $$\nDECLARE\n  v_Text text;\n  v_cnt  integer := 42;\nBEGIN\n  CALL p1(v_cnt := v_cnt);  -- error, must supply something for v_Text\n  RAISE NOTICE '%', v_Text;\nEND;\n$$",
-  "plpgsql_call-33.sql": "DO $$\nDECLARE\n  v_Text text;\n  v_cnt  integer := 42;\nBEGIN\n  CALL p1(v_cnt := v_cnt, v_Text := v_Text);\n  RAISE NOTICE '%', v_Text;\nEND;\n$$",
-  "plpgsql_call-34.sql": "DO $$\nDECLARE\n  v_Text text;\nBEGIN\n  CALL p1(10, v_Text := v_Text);\n  RAISE NOTICE '%', v_Text;\nEND;\n$$",
-  "plpgsql_call-35.sql": "DO $$\nDECLARE\n  v_Text text;\n  v_cnt  integer;\nBEGIN\n  CALL p1(v_Text := v_Text, v_cnt := v_cnt);\n  RAISE NOTICE '%', v_Text;\nEND;\n$$",
-  "plpgsql_call-36.sql": "CREATE PROCEDURE inner_p (f1 int)\nAS $$\nBEGIN\n  RAISE NOTICE 'inner_p(%)', f1;\nEND\n$$ LANGUAGE plpgsql",
-  "plpgsql_call-37.sql": "CREATE PROCEDURE outer_p (f1 int)\nAS $$\nBEGIN\n  RAISE NOTICE 'outer_p(%)', f1;\n  CALL inner_p(f(f1));\nEND\n$$ LANGUAGE plpgsql",
-  "plpgsql_call-38.sql": "CREATE FUNCTION outer_f (f1 int) RETURNS void\nAS $$\nBEGIN\n  RAISE NOTICE 'outer_f(%)', f1;\n  CALL inner_p(f(f1));\nEND\n$$ LANGUAGE plpgsql",
-  "plpgsql_call-39.sql": "CREATE FUNCTION f_get_x () RETURNS int\nAS $$\nDECLARE l_result int;\nBEGIN\n  SELECT x INTO l_result FROM t_test;\n  RETURN l_result;\nEND\n$$ LANGUAGE plpgsql STABLE",
-  "plpgsql_call-40.sql": "CREATE PROCEDURE f_print_x (x int)\nAS $$\nBEGIN\n  RAISE NOTICE 'f_print_x(%)', x;\nEND\n$$ LANGUAGE plpgsql",
-  "plpgsql_call-41.sql": "DO $$\nBEGIN\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\n  ROLLBACK;\nEND\n$$",
-  "plpgsql_call-42.sql": "DO $$\nBEGIN\n BEGIN\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\n EXCEPTION WHEN division_by_zero THEN\n   RAISE NOTICE '%', SQLERRM;\n END;\n  ROLLBACK;\nEND\n$$",
-  "plpgsql_call-43.sql": "DO $$\nBEGIN\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\nEND\n$$",
+  "plpgsql_call-26.sql": "CREATE PROCEDURE test_proc11(a OUT int, VARIADIC b int[])\nLANGUAGE plpgsql\nAS $$\nBEGIN\n  RAISE NOTICE 'a: %, b: %', a, b;\n  a := b[1] + b[2];\nEND;\n$$",
+  "plpgsql_call-27.sql": "DO $$\nDECLARE _a int; _b int; _c int;\nBEGIN\n  _a := 10; _b := 30; _c := 7;\n  CALL test_proc11(_a, _b, _c);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\nEND\n$$",
+  "plpgsql_call-28.sql": "CREATE PROCEDURE test_proc12(a anyelement, OUT b anyelement, OUT c anyarray)\nLANGUAGE plpgsql\nAS $$\nBEGIN\n  RAISE NOTICE 'a: %', a;\n  b := a;\n  c := array[a];\nEND;\n$$",
+  "plpgsql_call-29.sql": "DO $$\nDECLARE _a int; _b int; _c int[];\nBEGIN\n  _a := 10;\n  CALL test_proc12(_a, _b, _c);\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\nEND\n$$",
+  "plpgsql_call-30.sql": "DO $$\nDECLARE _a int; _b int; _c text[];\nBEGIN\n  _a := 10;\n  CALL test_proc12(_a, _b, _c);  -- error\n  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;\nEND\n$$",
+  "plpgsql_call-31.sql": "CREATE FUNCTION triggerfunc1() RETURNS trigger\nLANGUAGE plpgsql\nAS $$\nDECLARE\n    z int := 0;\nBEGIN\n    CALL test_proc6(2, NEW.a, NEW.a);\n    RETURN NEW;\nEND;\n$$",
+  "plpgsql_call-32.sql": "CREATE PROCEDURE p1(v_cnt int, v_Text inout text = NULL)\nAS $$\nBEGIN\n  v_Text := 'v_cnt = ' || v_cnt;\nEND\n$$ LANGUAGE plpgsql",
+  "plpgsql_call-33.sql": "DO $$\nDECLARE\n  v_Text text;\n  v_cnt  integer := 42;\nBEGIN\n  CALL p1(v_cnt := v_cnt);  -- error, must supply something for v_Text\n  RAISE NOTICE '%', v_Text;\nEND;\n$$",
+  "plpgsql_call-34.sql": "DO $$\nDECLARE\n  v_Text text;\n  v_cnt  integer := 42;\nBEGIN\n  CALL p1(v_cnt := v_cnt, v_Text := v_Text);\n  RAISE NOTICE '%', v_Text;\nEND;\n$$",
+  "plpgsql_call-35.sql": "DO $$\nDECLARE\n  v_Text text;\nBEGIN\n  CALL p1(10, v_Text := v_Text);\n  RAISE NOTICE '%', v_Text;\nEND;\n$$",
+  "plpgsql_call-36.sql": "DO $$\nDECLARE\n  v_Text text;\n  v_cnt  integer;\nBEGIN\n  CALL p1(v_Text := v_Text, v_cnt := v_cnt);\n  RAISE NOTICE '%', v_Text;\nEND;\n$$",
+  "plpgsql_call-37.sql": "CREATE PROCEDURE inner_p (f1 int)\nAS $$\nBEGIN\n  RAISE NOTICE 'inner_p(%)', f1;\nEND\n$$ LANGUAGE plpgsql",
+  "plpgsql_call-38.sql": "CREATE PROCEDURE outer_p (f1 int)\nAS $$\nBEGIN\n  RAISE NOTICE 'outer_p(%)', f1;\n  CALL inner_p(f(f1));\nEND\n$$ LANGUAGE plpgsql",
+  "plpgsql_call-39.sql": "CREATE FUNCTION outer_f (f1 int) RETURNS void\nAS $$\nBEGIN\n  RAISE NOTICE 'outer_f(%)', f1;\n  CALL inner_p(f(f1));\nEND\n$$ LANGUAGE plpgsql",
+  "plpgsql_call-40.sql": "CREATE FUNCTION f_get_x () RETURNS int\nAS $$\nDECLARE l_result int;\nBEGIN\n  SELECT x INTO l_result FROM t_test;\n  RETURN l_result;\nEND\n$$ LANGUAGE plpgsql STABLE",
+  "plpgsql_call-41.sql": "CREATE PROCEDURE f_print_x (x int)\nAS $$\nBEGIN\n  RAISE NOTICE 'f_print_x(%)', x;\nEND\n$$ LANGUAGE plpgsql",
+  "plpgsql_call-42.sql": "DO $$\nBEGIN\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\n  ROLLBACK;\nEND\n$$",
+  "plpgsql_call-43.sql": "DO $$\nBEGIN\n BEGIN\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\n EXCEPTION WHEN division_by_zero THEN\n   RAISE NOTICE '%', SQLERRM;\n END;\n  ROLLBACK;\nEND\n$$",
+  "plpgsql_call-44.sql": "DO $$\nBEGIN\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\n  UPDATE t_test SET x = x + 1;\n  RAISE NOTICE 'f_get_x(%)', f_get_x();\n  CALL f_print_x(f_get_x());\nEND\n$$",
   "plpgsql_cache-1.sql": "create function c_sillyaddone(int) returns int language plpgsql as\n$$ declare r c_mutable; begin r.f1 := $1; return r.f1 + 1; end $$",
   "plpgsql_cache-2.sql": "create function show_result_type(text) returns text language plpgsql as\n$$\n    declare\n        r record;\n        t text;\n    begin\n        execute $1 into r;\n        select pg_typeof(r.a) into t;\n        return format('type %s value %s', t, r.a::text);\n    end;\n$$",
   "plpgsql_array-1.sql": "do $$ declare a int[];\nbegin a := array[1,2]; a[3] := 4; raise notice 'a = %', a; end$$",

__fixtures__/plpgsql/plpgsql_deparser_fixes.sql

@@ -815,3 +815,25 @@ BEGIN
   updated.updated_at := now();
   RETURN updated;
 END$$;
+
+-- Test 66: assignment whose value is a call using named arguments
+CREATE FUNCTION test_assign_named_args() RETURNS text
+LANGUAGE plpgsql AS $$
+DECLARE
+  v_body text;
+BEGIN
+  v_body := ast_helpers.create_function(v_schema_name := 'app_public', v_function_name := 'f');
+  RETURN v_body;
+END$$;
+
+-- Test 67: field and subscript assignment targets with named-argument values
+CREATE FUNCTION test_assign_targets() RETURNS void
+LANGUAGE plpgsql AS $$
+DECLARE
+  a int[] := ARRAY[1, 2];
+  r record;
+BEGIN
+  SELECT 1 AS f INTO r;
+  a[2] := coalesce(nullif(3, 0), 4);
+  r.f := greatest(1, 2);
+END$$;

packages/plpgsql-deparser/__tests__/__snapshots__/deparser-fixes.test.ts.snap

@@ -276,6 +276,15 @@ EXCEPTION
 END"
 `;
 
+exports[`plpgsql-deparser bug fixes assignment targets vs named arguments should keep the target when the value uses named arguments 1`] = `
+"DECLARE
+  v_body text;
+BEGIN
+  v_body := ast_helpers.create_function(v_schema_name := 'app_public', v_function_name := 'f');
+  RETURN v_body;
+END"
+`;
+
 exports[`plpgsql-deparser bug fixes bare RAISE re-throw should keep a bare RAISE bare (not RAISE EXCEPTION;) 1`] = `
 "BEGIN
   PERFORM 1;

packages/plpgsql-deparser/__tests__/deparser-fixes.test.ts

@@ -1,6 +1,6 @@
 import { loadModule, parsePlPgSQLSync } from 'libpg-query';
 
-import { deparseSync, PLpgSQLParseResult } from '../src';
+import { deparseSync, ParseMode, PLpgSQLParseResult } from '../src';
 import { PLpgSQLTestUtils } from '../test-utils';
 
 describe('plpgsql-deparser bug fixes', () => {
@@ -1216,6 +1216,112 @@ END$$`;
     });
   });
 
+  describe('assignment targets vs named arguments', () => {
+    it('should keep the target when the value uses named arguments', async () => {
+      const sql = `CREATE FUNCTION test_assign_named_args() RETURNS text
+LANGUAGE plpgsql AS $$
+DECLARE
+  v_body text;
+BEGIN
+  v_body := ast_helpers.create_function(v_schema_name := 'app_public', v_function_name := 'f');
+  RETURN v_body;
+END$$`;
+
+      await testUtils.expectAstMatch('assignment with named arguments', sql);
+
+      const parsed = parsePlPgSQLSync(sql) as unknown as PLpgSQLParseResult;
+      const deparsed = deparseSync(parsed);
+      expect(deparsed).toMatchSnapshot();
+      expect(deparsed).toContain(
+        `v_body := ast_helpers.create_function(v_schema_name := 'app_public', v_function_name := 'f');`
+      );
+    });
+
+    it('should emit a self-contained assignment exactly once', async () => {
+      const sql = `CREATE FUNCTION test_assign_self_contained(n int) RETURNS int
+LANGUAGE plpgsql AS $$
+DECLARE
+  sum int := 0;
+BEGIN
+  sum := sum + n;
+  RETURN sum;
+END$$`;
+
+      await testUtils.expectAstMatch('self-contained assignment', sql);
+
+      const parsed = parsePlPgSQLSync(sql) as unknown as PLpgSQLParseResult;
+      const deparsed = deparseSync(parsed);
+      expect(deparsed).toContain('sum := sum + n;');
+      expect(deparsed).not.toContain('sum := sum := ');
+    });
+
+    it('should keep field and subscript targets', async () => {
+      const sql = `CREATE FUNCTION test_assign_targets() RETURNS void
+LANGUAGE plpgsql AS $$
+DECLARE
+  a int[] := ARRAY[1, 2];
+  r record;
+BEGIN
+  SELECT 1 AS f INTO r;
+  a[2] := coalesce(nullif(3, 0), 4);
+  r.f := greatest(1, 2);
+END$$`;
+
+      await testUtils.expectAstMatch('field and subscript assignment targets', sql);
+
+      const parsed = parsePlPgSQLSync(sql) as unknown as PLpgSQLParseResult;
+      const deparsed = deparseSync(parsed);
+      expect(deparsed).toContain('a[2] := coalesce(nullif(3, 0), 4);');
+      expect(deparsed).toContain('r.f := greatest(1, 2);');
+    });
+
+    const buildAssign = (query: string, parseMode?: number): PLpgSQLParseResult => ({
+      plpgsql_funcs: [
+        {
+          PLpgSQL_function: {
+            datums: [{ PLpgSQL_var: { refname: 'v_x' } }],
+            action: {
+              PLpgSQL_stmt_block: {
+                body: [
+                  {
+                    PLpgSQL_stmt_assign: {
+                      varno: 0,
+                      expr: { PLpgSQL_expr: { query, parseMode } },
+                    },
+                  },
+                ],
+              },
+            },
+          },
+        },
+      ],
+    });
+
+    it('should keep the target of a hand-built assignment whose value uses named arguments', () => {
+      const deparsed = deparseSync(
+        buildAssign(`ast_helpers.create_function(v_schema_name := 'app_public', v_function_name := 'f')`)
+      );
+
+      expect(deparsed).toContain(
+        `v_x := ast_helpers.create_function(v_schema_name := 'app_public', v_function_name := 'f');`
+      );
+    });
+
+    // A missing parseMode is treated as "not an assignment parse mode": the query
+    // text is the value only, and the target comes from varno.
+    it('should treat an absent parseMode as a value-only expression', () => {
+      expect(deparseSync(buildAssign('1 + 1'))).toContain('v_x := 1 + 1;');
+      expect(deparseSync(buildAssign('v_x := 1'))).toContain('v_x := v_x := 1;');
+      expect(deparseSync(buildAssign('v_x := 1', ParseMode.RAW_PARSE_PLPGSQL_ASSIGN1))).toContain('v_x := 1;');
+    });
+
+    it('should un-parenthesize a subscripted target carried in the query text', () => {
+      const deparsed = deparseSync(buildAssign('(v_x)[2] := 5', ParseMode.RAW_PARSE_PLPGSQL_ASSIGN3));
+
+      expect(deparsed).toContain('v_x[2] := 5;');
+    });
+  });
+
   describe('uppercase %ROWTYPE/%TYPE references', () => {
     it('should not quote uppercase %ROWTYPE and %TYPE references', async () => {
       const sql = `CREATE FUNCTION test_rowtype_case() RETURNS void

packages/plpgsql-deparser/src/plpgsql-deparser.ts

@@ -13,6 +13,7 @@
 
 import { QuoteUtils } from 'pgsql-deparser';
 
+import { ParseMode } from './hydrate-types';
 import {
   DiagItemKind,
   ElogLevel,
@@ -59,6 +60,18 @@ import {
   RaiseOptionType,
 } from './types';
 
+/**
+ * PostgreSQL parses the right-hand side of an assignment in a dedicated raw
+ * parse mode per target shape — RAW_PARSE_PLPGSQL_ASSIGN1 (3), ASSIGN2 (4) and
+ * ASSIGN3 (5) for `var`, `var.field` and `var.field[...]` targets — and that
+ * mode is preserved on `PLpgSQL_expr.parseMode`. In those modes the stored
+ * query text is the entire assignment, target included (`cnt := cnt + 1`);
+ * every lower mode (RAW_PARSE_DEFAULT, RAW_PARSE_TYPE_NAME,
+ * RAW_PARSE_PLPGSQL_EXPR) is a plain expression/statement parse whose text is
+ * only the value.
+ */
+const LOWEST_ASSIGN_PARSE_MODE = ParseMode.RAW_PARSE_PLPGSQL_ASSIGN1;
+
 export interface PLpgSQLDeparserOptions {
   indent?: string;
   newline?: string;
@@ -1129,19 +1142,35 @@ export class PLpgSQLDeparser {
   private deparseAssign(assign: PLpgSQL_stmt_assign, context: PLpgSQLDeparserContext): string {
     const varName = this.getVarName(assign.varno, context);
     const expr = assign.expr ? this.deparseExpr(assign.expr) : '';
-    
-    // The expression already contains the assignment in the query
-    // e.g., "sum := sum + n"
-    if (expr.includes(':=')) {
+    const parseMode = assign.expr?.PLpgSQL_expr?.parseMode;
+
+    if (this.exprCarriesAssignmentTarget(parseMode)) {
       // The SQL deparser parenthesizes subscripted targets like '(a)[2]',
       // but the PL/pgSQL assignment grammar requires a bare identifier
       // before subscripts/field selections.
       return expr.replace(/^\((\w+(?:\.\w+)*)\)(?=\[|\.)/, '$1');
     }
-    
+
     return `${varName} := ${expr}`;
   }
 
+  /**
+   * Whether the stored query text of an assignment already spells out the
+   * assignment target, so that prefixing the target again would emit it twice.
+   *
+   * The parse mode answers this exactly. A substring test for ':=' cannot: ':='
+   * is also PostgreSQL's named-argument operator, so a value like `f(a := 1)`
+   * reads as self-contained and the target gets silently dropped.
+   *
+   * An absent parseMode — hand-built nodes, or output from a PostgreSQL older
+   * than the assignment parse modes — means the same as mode 0: the text is the
+   * value only and the target comes from `varno`. A hand-built node that does
+   * embed its target in the text must say so with `parseMode`.
+   */
+  private exprCarriesAssignmentTarget(parseMode?: number): boolean {
+    return (parseMode ?? ParseMode.RAW_PARSE_DEFAULT) >= LOWEST_ASSIGN_PARSE_MODE;
+  }
+
   /**
    * Deparse an IF statement
    */