Fix blank Query Tool screen caused by a malformed runtime locale (#7596)

docs/en_US/release_notes_9_16.rst

@@ -42,6 +42,7 @@ Bug fixes
 *********
 
   | `Issue #6308 <https://github.com/pgadmin-org/pgadmin4/issues/6308>`_ -  Fix the infinite loading spinner after an idle database connection is silently dropped, by detecting stale connections and offering a reconnect dialog.
+  | `Issue #7596 <https://github.com/pgadmin-org/pgadmin4/issues/7596>`_ -  Fix the Query Tool turning into a blank white screen when the runtime has a malformed default locale, by guarding the Query History date/time formatting against the resulting RangeError.
   | `Issue #9091 <https://github.com/pgadmin-org/pgadmin4/issues/9091>`_ -  Fix the Query Tool re-prompting for an unsaved password in a loop and rejecting the re-entered password, by caching the entered password on the server manager when the primary connection is already established.
   | `Issue #9595 <https://github.com/pgadmin-org/pgadmin4/issues/9595>`_ -  Fix missing ALTER ... SET DEFAULT statements for inherited columns in the generated table SQL/EDIT script.
   | `Issue #9677 <https://github.com/pgadmin-org/pgadmin4/issues/9677>`_ -  Fix the Unlogged table toggle in table properties not generating any ALTER TABLE ... SET LOGGED/UNLOGGED statement.

web/pgadmin/tools/sqleditor/static/js/components/sections/QueryHistory.jsx

@@ -124,12 +124,27 @@ export const QuerySources = {
   },
 };
 
-function getDateFormatted(date) {
-  return date.toLocaleDateString();
+// On some runtimes the default locale (derived from the OS/environment) is
+// malformed, which makes Date.prototype.toLocaleDateString/toLocaleTimeString
+// throw "RangeError: Incorrect locale information provided". As these are
+// called while rendering the Query History panel, an uncaught throw unmounts
+// the whole SQL editor and the user sees a blank white screen, losing any
+// unsaved work. Fall back to a moment-based format (moment uses its own
+// locale data and does not depend on the broken Intl default). See #7596.
+export function getDateFormatted(date) {
+  try {
+    return date.toLocaleDateString();
+  } catch {
+    return moment(date).format('L');
+  }
 }
 
-function getTimeFormatted(time) {
-  return time.toLocaleTimeString();
+export function getTimeFormatted(time) {
+  try {
+    return time.toLocaleTimeString();
+  } catch {
+    return moment(time).format('LTS');
+  }
 }
 
 class QueryHistoryUtils {

web/regression/javascript/sqleditor/QueryHistory.spec.js

@@ -0,0 +1,85 @@
+/////////////////////////////////////////////////////////////
+//
+// pgAdmin 4 - PostgreSQL Tools
+//
+// Copyright (C) 2013 - 2025, The pgAdmin Development Team
+// This software is released under the PostgreSQL Licence
+//
+//////////////////////////////////////////////////////////////
+
+// Mock url_for
+jest.mock('sources/url_for', () => ({
+  __esModule: true,
+  default: jest.fn((endpoint) => `/mock/${endpoint}`),
+}));
+
+// Mock the QueryToolComponent to avoid importing all its dependencies
+jest.mock('../../../pgadmin/tools/sqleditor/static/js/components/QueryToolComponent.jsx', () => {
+  const React = require('react');
+  return {
+    QueryToolContext: React.createContext(null),
+    QueryToolConnectionContext: React.createContext(null),
+    QueryToolEventsContext: React.createContext(null),
+  };
+});
+
+// Mock CodeMirror
+jest.mock('../../../pgadmin/static/js/components/ReactCodeMirror', () => ({
+  __esModule: true,
+  default: ({ value }) => value,
+}));
+
+import { getDateFormatted, getTimeFormatted } from '../../../pgadmin/tools/sqleditor/static/js/components/sections/QueryHistory.jsx';
+
+describe('QueryHistory date/time formatting', () => {
+  it('formats a date using the native locale formatter', () => {
+    const date = new Date(2025, 0, 15);
+    expect(getDateFormatted(date)).toBe(date.toLocaleDateString());
+  });
+
+  it('formats a time using the native locale formatter', () => {
+    const time = new Date(2025, 0, 15, 10, 30, 45);
+    expect(getTimeFormatted(time)).toBe(time.toLocaleTimeString());
+  });
+
+  // Regression test for #7596: a malformed default locale makes
+  // toLocaleDateString/toLocaleTimeString throw "RangeError: Incorrect
+  // locale information provided". The helpers must not propagate the throw
+  // (which would white-screen the SQL editor) and must return a usable
+  // string instead.
+  describe('when the runtime locale is broken', () => {
+    let dateSpy, timeSpy;
+
+    beforeEach(() => {
+      dateSpy = jest.spyOn(Date.prototype, 'toLocaleDateString')
+        .mockImplementation(() => {
+          throw new RangeError('Incorrect locale information provided');
+        });
+      timeSpy = jest.spyOn(Date.prototype, 'toLocaleTimeString')
+        .mockImplementation(() => {
+          throw new RangeError('Incorrect locale information provided');
+        });
+    });
+
+    afterEach(() => {
+      dateSpy.mockRestore();
+      timeSpy.mockRestore();
+    });
+
+    it('does not throw and returns a non-empty date string', () => {
+      const date = new Date(2025, 0, 15);
+      let result;
+      expect(() => { result = getDateFormatted(date); }).not.toThrow();
+      expect(typeof result).toBe('string');
+      expect(result.length).toBeGreaterThan(0);
+    });
+
+    it('does not throw and returns a non-empty time string', () => {
+      const time = new Date(2025, 0, 15, 10, 30, 45);
+      let result;
+      expect(() => { result = getTimeFormatted(time); }).not.toThrow();
+      expect(typeof result).toBe('string');
+      expect(result.length).toBeGreaterThan(0);
+    });
+  });
+});