[IMP] odoo/tests: reporting & handling of chrome start issues

If we can't find the devtools port file after 10 seconds we skip the
test, however

- this is an invisible error because the runbot does not surface
  skipped tests, so this specific variant should also have a warning
  (also the skip from not finding a chrome executable)
- if chrome started but got stuck before it managed to create the port
  file we don't `stop` the chromebrowser as it never finished
  starting, however this means we leave a chrome running in the void
  a `user_data_dir` littering the machine / vm's tempdir

So improve the handling of that bit. Also have chrome write its stderr
to a file (in the `user_data_dir`) so we can log that out in case it
contains useful information as to why chrome didn't finish booting.

While at it backport the spawn changes from odoo#206574 for consistency
and simplicity: we don't need to test the platform for every single
tour and the indirection makes updating the `Popen` parameters
unnecessary complicated.

closes odoo#232612

Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>

Author: xmo-odoo

odoo/tests/common.py

@@ -920,6 +920,17 @@ def save_test_file(test_name, content, prefix, extension='png', logger=_logger,
     logger.runbot(f'{document_type} in: {full_path}')
 
 
+if os.name == 'posix' and platform.system() != 'Darwin':
+    # since the introduction of pointer compression in Chrome 80 (v8 v8.0),
+    # the memory reservation algorithm requires more than 8GiB of
+    # virtual mem for alignment this exceeds our default memory limits.
+    def _preexec():
+        import resource  # noqa: PLC0415
+        resource.setrlimit(resource.RLIMIT_AS, (resource.RLIM_INFINITY, resource.RLIM_INFINITY))
+else:
+    _preexec = None
+
+
 class ChromeBrowser:
     """ Helper object to control a Chrome headless process. """
     remote_debugging_port = 0  # 9222, change it in a non-git-tracked file
@@ -1049,31 +1060,35 @@ def executable(self):
                 if os.path.exists(bin_):
                     return bin_
 
+        self._logger.warning('Chrome executable not found')
         raise unittest.SkipTest("Chrome executable not found")
 
-    def _chrome_without_limit(self, cmd):
-        if os.name == 'posix' and platform.system() != 'Darwin':
-            # since the introduction of pointer compression in Chrome 80 (v8 v8.0),
-            # the memory reservation algorithm requires more than 8GiB of
-            # virtual mem for alignment this exceeds our default memory limits.
-            def preexec():
-                import resource
-                resource.setrlimit(resource.RLIMIT_AS, (resource.RLIM_INFINITY, resource.RLIM_INFINITY))
-        else:
-            preexec = None
-
-        # pylint: disable=subprocess-popen-preexec-fn
-        return subprocess.Popen(cmd, stderr=subprocess.DEVNULL, preexec_fn=preexec)
-
     def _spawn_chrome(self, cmd):
-        proc = self._chrome_without_limit(cmd)
+        log_path = pathlib.Path(self.user_data_dir, 'err.log')
+        with log_path.open('wb') as log_file:
+            # pylint: disable=subprocess-popen-preexec-fn
+            proc = subprocess.Popen(cmd, stderr=log_file, preexec_fn=_preexec)  # noqa: PLW1509
+
         port_file = pathlib.Path(self.user_data_dir, 'DevToolsActivePort')
         for _ in range(CHECK_BROWSER_ITERATIONS):
             time.sleep(CHECK_BROWSER_SLEEP)
             if port_file.is_file() and port_file.stat().st_size > 5:
                 with port_file.open('r', encoding='utf-8') as f:
                     self.devtools_port = int(f.readline())
                     return proc.pid
+
+        if proc.poll() is None:
+            proc.terminate()
+            try:
+                proc.wait(5)
+            except subprocess.TimeoutExpired:
+                proc.kill()
+                proc.wait()
+        self._logger.warning('Chrome headless failed to start:\n%s', log_path.read_text(encoding="utf-8"))
+        # since the chrome never started, it's not going to be `stop`-ed so we
+        # need to cleanup the directory here
+        shutil.rmtree(self.user_data_dir, ignore_errors=True)
+
         raise unittest.SkipTest(f'Failed to detect chrome devtools port after {BROWSER_WAIT :.1f}s.')
 
     def _chrome_start(self):