translation: skip strings which can not be serialized

When string serialization fails, skip the string, unmark it as pending
and continue in other pending strings. The error is stored as a Change
object and the string is marked as needing editing.

This makes it possible to recover from the situation, but the string can
be lost as it is not serialized, the change will disappear on next upstream
update.

Right now this happens frequently with Fluent, but can happen with other
formats as well.

Fixes #9775

docs/changes.rst

@@ -16,6 +16,7 @@ Not yet released.
 * Configure VCS API credentials as a Python dict from environment variables.
 * Improved accuracy of checks on plural messages.
 * Enage page better shows stats.
+* Strings which can not be saved to a file no longer block other strings to be written.
 
 **Bug fixes**
 

weblate/formats/ttkit.py

@@ -2045,10 +2045,18 @@ def fixup(self, store):
 
 class FluentUnit(MonolingualSimpleUnit):
     def set_target(self, target: str | list[str]):
+        old_target = self.unit.target
+        old_source = self.unit.source
         super().set_target(target)
         self.unit.source = target
-        # This triggers serialization discovering any syntax issues
-        self.unit.to_entry()
+        try:
+            # This triggers serialization discovering any syntax issues
+            self.unit.to_entry()
+        except Exception:
+            # Restore previous content
+            self.unit.target = old_target
+            self.unit.source = old_source
+            raise
 
     @cached_property
     def flags(self):

weblate/trans/migrations/0004_alter_change_action.py

@@ -0,0 +1,91 @@
+# Copyright © Michal Čihař <[email protected]>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Generated by Django 4.2.5 on 2023-10-05 10:40
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("trans", "0003_alter_project_access_control"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="change",
+            name="action",
+            field=models.IntegerField(
+                choices=[
+                    (0, "Resource update"),
+                    (1, "Translation completed"),
+                    (2, "Translation changed"),
+                    (5, "New translation"),
+                    (3, "Comment added"),
+                    (4, "Suggestion added"),
+                    (6, "Automatic translation"),
+                    (7, "Suggestion accepted"),
+                    (8, "Translation reverted"),
+                    (9, "Translation uploaded"),
+                    (13, "New source string"),
+                    (14, "Component locked"),
+                    (15, "Component unlocked"),
+                    (17, "Committed changes"),
+                    (18, "Pushed changes"),
+                    (19, "Reset repository"),
+                    (20, "Merged repository"),
+                    (21, "Rebased repository"),
+                    (22, "Failed merge on repository"),
+                    (23, "Failed rebase on repository"),
+                    (28, "Failed push on repository"),
+                    (24, "Parse error"),
+                    (25, "Removed translation"),
+                    (26, "Suggestion removed"),
+                    (27, "Search and replace"),
+                    (29, "Suggestion removed during cleanup"),
+                    (30, "Source string changed"),
+                    (31, "New string added"),
+                    (32, "Bulk status change"),
+                    (33, "Changed visibility"),
+                    (34, "Added user"),
+                    (35, "Removed user"),
+                    (36, "Translation approved"),
+                    (37, "Marked for edit"),
+                    (38, "Removed component"),
+                    (39, "Removed project"),
+                    (41, "Renamed project"),
+                    (42, "Renamed component"),
+                    (43, "Moved component"),
+                    (44, "New string to translate"),
+                    (45, "New contributor"),
+                    (46, "New announcement"),
+                    (47, "New alert"),
+                    (48, "Added new language"),
+                    (49, "Requested new language"),
+                    (50, "Created project"),
+                    (51, "Created component"),
+                    (52, "Invited user"),
+                    (53, "Received repository notification"),
+                    (54, "Replaced file by upload"),
+                    (55, "License changed"),
+                    (56, "Contributor agreement changed"),
+                    (57, "Screnshot added"),
+                    (58, "Screnshot uploaded"),
+                    (59, "String updated in the repository"),
+                    (60, "Add-on installed"),
+                    (61, "Add-on configuration changed"),
+                    (62, "Add-on uninstalled"),
+                    (63, "Removed string"),
+                    (64, "Removed comment"),
+                    (65, "Resolved comment"),
+                    (66, "Explanation updated"),
+                    (67, "Removed category"),
+                    (68, "Renamed category"),
+                    (69, "Moved category"),
+                    (70, "Could not save string"),
+                ],
+                default=2,
+            ),
+        ),
+    ]

weblate/trans/models/change.py

@@ -292,6 +292,7 @@ class Change(models.Model, UserDisplayMixin):
     ACTION_REMOVE_CATEGORY = 67
     ACTION_RENAME_CATEGORY = 68
     ACTION_MOVE_CATEGORY = 69
+    ACTION_SAVE_FAILED = 70
 
     ACTION_CHOICES = (
         # Translators: Name of event in the history
@@ -431,6 +432,8 @@ class Change(models.Model, UserDisplayMixin):
         (ACTION_RENAME_CATEGORY, gettext_lazy("Renamed category")),
         # Translators: Name of event in the history
         (ACTION_MOVE_CATEGORY, gettext_lazy("Moved category")),
+        # Translators: Name of event in the history
+        (ACTION_SAVE_FAILED, gettext_lazy("Could not save string")),
     )
     ACTIONS_DICT = dict(ACTION_CHOICES)
     ACTION_STRINGS = {

weblate/trans/models/component.py

@@ -2019,15 +2019,19 @@ def commit_files(
 
             return True
 
-    def handle_parse_error(
-        self, error, translation=None, filename=None, reraise: bool = True
-    ):
-        """Handler for parse errors."""
+    def get_parse_error_message(self, error) -> str:
         error_message = getattr(error, "strerror", "")
         if not error_message:
             error_message = getattr(error, "message", "")
         if not error_message:
             error_message = str(error).replace(self.full_path, "")
+        return error_message
+
+    def handle_parse_error(
+        self, error, translation=None, filename=None, reraise: bool = True
+    ):
+        """Handler for parse errors."""
+        error_message = self.get_parse_error_message(error)
         if filename is None:
             filename = self.template if translation is None else translation.filename
         self.trigger_alert("ParseError", error=error_message, filename=filename)

weblate/trans/models/translation.py

@@ -766,10 +766,17 @@ def update_units(self, units, store, author_name, author_id):
                     pounit.set_explanation(unit.explanation)
                     pounit.set_source_explanation(unit.source_unit.explanation)
                 except Exception as error:
-                    self.component.handle_parse_error(error, self, reraise=False)
                     report_error(
                         cause="Could not update unit", project=self.component.project
                     )
+                    unit.state = STATE_FUZZY
+                    # Use update instead of hitting expensive save()
+                    Unit.objects.filter(pk=unit.pk).update(state=STATE_FUZZY)
+                    unit.change_set.create(
+                        action=Change.ACTION_SAVE_FAILED,
+                        target=self.get_parse_error_message(error),
+                    )
+                    clear_pending.append(unit.pk)
                     continue
 
                 updated = True