Bugzilla

Discussing it with :willdurand on Slack, and he agrees that skipping a non-existent manifest doesn't feel right.

Maybe this is sensible enough (only ignore `features*` missing manifests)

```
diff --git a/python/mozbuild/mozbuild/action/langpack_manifest.py b/python/mozbuild/mozbuild/action/langpack_manifest.py
--- a/python/mozbuild/mozbuild/action/langpack_manifest.py
+++ b/python/mozbuild/mozbuild/action/langpack_manifest.py
@@ -343,18 +343,23 @@ def convert_entry_flags_to_platform_code
 #            'platforms': ['win', 'mac'],
 #            'path': 'chrome/pl/locale/pl/autoconfig/'
 #        },
 #    ]
 ###
 def parse_chrome_manifest(path, base_path, chrome_entries):
     for entry in parse_manifest(None, path):
         if isinstance(entry, Manifest):
+            entry_path = os.path.join(os.path.dirname(path), entry.relpath)
+            # This is needed to work around the hack in browser/locales/jar.mn
+            # from bug 1240628, when there are no localized system add-ons.
+            if entry.relpath.startswith("features") and not os.path.exists(entry_path):
+                continue
             parse_chrome_manifest(
-                os.path.join(os.path.dirname(path), entry.relpath),
+                entry_path,
                 base_path,
                 chrome_entries,
             )
         elif isinstance(entry, ManifestLocale):
             entry_path = os.path.join(
                 os.path.relpath(os.path.dirname(path), base_path), entry.relpath
             )
             chrome_entries.append(
```

Discussing it with :willdurand on Slack, and he agrees that skipping a non-existent manifest doesn't feel right.

Maybe this is sensible enough (only ignore `features*` missing manifests)

```diff
diff --git a/python/mozbuild/mozbuild/action/langpack_manifest.py b/python/mozbuild/mozbuild/action/langpack_manifest.py
--- a/python/mozbuild/mozbuild/action/langpack_manifest.py
+++ b/python/mozbuild/mozbuild/action/langpack_manifest.py
@@ -343,18 +343,23 @@ def convert_entry_flags_to_platform_code
 #            'platforms': ['win', 'mac'],
 #            'path': 'chrome/pl/locale/pl/autoconfig/'
 #        },
 #    ]
 ###
 def parse_chrome_manifest(path, base_path, chrome_entries):
     for entry in parse_manifest(None, path):
         if isinstance(entry, Manifest):
+            entry_path = os.path.join(os.path.dirname(path), entry.relpath)
+            # This is needed to work around the hack in browser/locales/jar.mn
+            # from bug 1240628, when there are no localized system add-ons.
+            if entry.relpath.startswith("features") and not os.path.exists(entry_path):
+                continue
             parse_chrome_manifest(
-                os.path.join(os.path.dirname(path), entry.relpath),
+                entry_path,
                 base_path,
                 chrome_entries,
             )
         elif isinstance(entry, ManifestLocale):
             entry_path = os.path.join(
                 os.path.relpath(os.path.dirname(path), base_path), entry.relpath
             )
             chrome_entries.append(
```