Backup restore logging drops cog names and raises TypeError for failed libraries

[potatosips]

What Red version are you using?

3.5.25.dev1 (V3/develop @ 61484f2)

What were you trying to do?

Restore third-party cogs from a Red backup with redbot-setup restore. I audited the failure reporting in redbot.core._downloader._restore_from_backup() because these messages are the only diagnostic output when a cog cannot be restored.

What did you expect to happen?

Every restore failure should produce a normal log record containing the cog name, repository name, and failed shared-library names. Logging a recovery failure must not itself raise a formatting exception.

What actually happened?

Three log calls in the restore path have missing format arguments.

• Lines 989 and 994 log The commit that %r cog... without passing cog.name, so the literal placeholder is printed instead of the affected cog.
• The failed_libs branch at lines 1066-1069 has three placeholders but passes only two arguments. Python logging raises TypeError: not enough arguments for format string, and the intended failure message is lost.

Observed output:

WARNING:The commit that %r cog was installed from is unknown ...
ERROR:The commit that %r cog was installed from is unknown ...
--- Logging error ---
TypeError: not enough arguments for format string
Message: 'Failed to reinstall shared libraries for %r cog from %r repo: %s'
Arguments: ('repo-name', 'lib-name')

How can we reproduce this error?

1. Check out V3/develop at 61484f28f7fcfff81309cb2b0b0d5287c921f1ad and install the test dependencies on Python 3.11.
2. Attach a logging.StreamHandler to red.core.downloader.
3. Exercise the two no-commit branches in _restore_from_backup(); both records retain a literal %r.
4. Return a CogInstallResult with a non-empty failed_libs tuple from install_cogs().
5. Observe the logging traceback above instead of the intended cog/repository/library diagnostic.

The same failure can be isolated with the production format string:

log.error(
    'Failed to reinstall shared libraries for %r cog from %r repo: %s',
    'repo-name',
    'lib-name',
)

Anything else?

Environment: Debian Bookworm arm64 container, Python 3.11.15. The unmodified baseline passes 313 passed, 7 skipped; pylint --errors-only redbot independently reports E1206 at line 1066. I searched open and closed issues for the exact messages, backup restore logging errors, failed shared libraries, and missing commit metadata; no duplicate was found.

Likely minimal fix: pass cog.name to both missing-commit messages, and pass cog.name, cog.repo.name, then the joined library names to the failed-libraries message. I will add regression coverage for all three formatted records separately.

[potatosips]

Implemented and verified separately after filing.

Fix

• Passes the missing cog name to both no-commit warning/error records.
• Passes cog name, repository name, and joined library names to the failed-shared-libraries record.
• Adds a regression test that drives all three real _restore_from_backup() branches with isolated config, repository, progress, and installer fakes.

Before/after proof

• Fresh unmodified V3/develop at 61484f2 plus the regression: 1 failed, reproducing TypeError: not enough arguments for format string; the other two captured records contain literal %r.
• Patched focused regression: 1 passed.
• Patched full suite: 314 passed, 7 skipped.
• python -m compileall -q redbot: passed.
• black --check redbot tests: passed; 231 files unchanged.
• pylint --errors-only redbot/core/_downloader/init.py: exit 0; the prior E1206 is gone.
• git diff --check: passed.
• The patch below passed git apply --check in a fresh clone at the exact reported commit.

Tested on Debian Bookworm arm64 with Python 3.11.15. No Discord token or live bot connection is required for this restore-path test.

Apply and verify

git checkout 61484f28f7fcfff81309cb2b0b0d5287c921f1ad
git apply red-discordbot-issue-6792-fix.patch
pytest -q tests/core/_downloader/test_restore.py
pytest -q

Complete apply-ready patch

diff --git a/redbot/core/_downloader/__init__.py b/redbot/core/_downloader/__init__.py
index 03cadc9..48305b1 100644
--- a/redbot/core/_downloader/__init__.py
+++ b/redbot/core/_downloader/__init__.py
@@ -988,12 +988,14 @@ async def _restore_from_backup() -> None:
                     cog = last_cog_occurrence
                     log.warning(
                         "The commit that %r cog was installed from is unknown"
-                        " - will try to reinstall from latest commit where it's still available."
+                        " - will try to reinstall from latest commit where it's still available.",
+                        cog.name,
                     )
                 else:
                     log.error(
                         "The commit that %r cog was installed from is unknown"
-                        " and it could not be found in the repo."
+                        " and it could not be found in the repo.",
+                        cog.name,
                     )
                     continue
 
@@ -1065,6 +1067,7 @@ async def _restore_from_backup() -> None:
             if install_result.failed_libs:
                 log.error(
                     "Failed to reinstall shared libraries for %r cog from %r repo: %s",
+                    cog.name,
                     cog.repo.name,
                     ", ".join([lib.name for lib in install_result.failed_libs]),
                 )
diff --git a/tests/core/_downloader/test_restore.py b/tests/core/_downloader/test_restore.py
new file mode 100644
index 0000000..2de3916
--- /dev/null
+++ b/tests/core/_downloader/test_restore.py
@@ -0,0 +1,100 @@
+import contextlib
+import logging
+from types import SimpleNamespace
+from unittest.mock import AsyncMock
+
+from redbot.core import _downloader as downloader
+
+
+class FakeProgress:
+    def add_task(self, description):
+        return 1
+
+    def track(self, sequence, *, task_id):
+        return sequence
+
+    def update(self, task_id, *, description):
+        pass
+
+
+@contextlib.contextmanager
+def fake_detailed_progress(*, unit):
+    yield FakeProgress()
+
+
+def install_result(*, failed_libs=()):
+    return downloader.CogInstallResult(
+        installed_cogs=(),
+        installed_libs=(),
+        failed_cogs=(),
+        failed_libs=failed_libs,
+        failed_reqs=(),
+        unavailable_cogs=(),
+        already_installed=(),
+        name_already_used=(),
+        incompatible_python_version=(),
+        incompatible_bot_version=(),
+    )
+
+
+async def test_restore_failure_logs_include_cog_and_repo_names(monkeypatch, tmp_path, caplog):
+    (tmp_path / "repos.json").write_text("[]", encoding="utf-8")
+
+    fallback_repo = SimpleNamespace(
+        name="fallback-repo",
+        get_last_module_occurrence=AsyncMock(),
+    )
+    missing_repo = SimpleNamespace(
+        name="missing-repo",
+        get_last_module_occurrence=AsyncMock(return_value=None),
+    )
+    failed_libs_repo = SimpleNamespace(name="failed-libs-repo")
+
+    fallback_cog = SimpleNamespace(name="fallback-cog", commit=None, repo=fallback_repo)
+    fallback_repo.get_last_module_occurrence.return_value = SimpleNamespace(
+        name="fallback-cog",
+        commit="fallback-commit",
+        disabled=False,
+        repo=fallback_repo,
+    )
+    missing_cog = SimpleNamespace(name="missing-cog", commit=None, repo=missing_repo)
+    failed_libs_cog = SimpleNamespace(
+        name="failed-libs-cog",
+        commit="failed-libs-commit",
+        repo=failed_libs_repo,
+    )
+
+    async def fake_install_cogs(repo, commit, cog_names):
+        if cog_names == ["failed-libs-cog"]:
+            return install_result(
+                failed_libs=(SimpleNamespace(name="lib-one"), SimpleNamespace(name="lib-two"))
+            )
+        return install_result()
+
+    fake_config = SimpleNamespace(
+        installed_cogs=SimpleNamespace(clear=AsyncMock()),
+        installed_libraries=SimpleNamespace(clear=AsyncMock()),
+    )
+    fake_repo_manager = SimpleNamespace(repos_folder=tmp_path / "repos")
+
+    monkeypatch.setattr(downloader, "_config", fake_config, raising=False)
+    monkeypatch.setattr(downloader, "_repo_manager", fake_repo_manager, raising=False)
+    monkeypatch.setattr(downloader, "detailed_progress", fake_detailed_progress)
+    monkeypatch.setattr(
+        downloader,
+        "installed_cogs",
+        AsyncMock(return_value=(fallback_cog, missing_cog, failed_libs_cog)),
+    )
+    monkeypatch.setattr(downloader, "install_cogs", fake_install_cogs)
+    caplog.set_level(logging.WARNING, logger=downloader.log.name)
+
+    await downloader._restore_from_backup()
+
+    assert caplog.messages == [
+        "The commit that 'fallback-cog' cog was installed from is unknown"
+        " - will try to reinstall from latest commit where it's still available.",
+        "The commit that 'missing-cog' cog was installed from is unknown"
+        " and it could not be found in the repo.",
+        "Failed to reinstall shared libraries for 'failed-libs-cog' cog"
+        " from 'failed-libs-repo' repo: lib-one, lib-two",
+    ]