fix(desktop): preserve updater failure causes in diagnostics

[Yash-Singh1]

Problem

Desktop updater failures reach persisted diagnostics with only generic messages and error tags. A local trace audit found 15 failed nightly update checks without the underlying reason, so the records could not distinguish a missing release feed from a network failure.

Change

Add bounded cause summaries to the desktop updater's diagnostic logs. The summaries preserve error codes, first-line messages, and nested failure reasons while redacting URLs and credential fields and omitting appended HTTP response bodies and headers. Check, download, install, poller, and updater-event handlers share the formatter.

Scope and approval

This is a focused fix for missing diagnostic information in the existing updater. It adds no setting or workflow and keeps user-visible update messages generic. All changes address the same loss of updater failure causes.

Verification

• vp test run apps/desktop/src/updates/DesktopUpdates.test.ts apps/desktop/src/updates/DesktopRemoteUpdates.test.ts: 54 tests passed. Regression coverage checks that rejected update checks and updater error events emit redacted causes while retaining generic update state messages. Formatter coverage verifies nested network errors, credential removal, bounded output, cyclic causes, and unreadable error objects.
• Targeted lint and formatting passed for the two changed files.
• vp run --filter @t3tools/desktop typecheck passed.

No live Electron update check was run. These changes improve failure diagnostics; the retained traces do not establish the cause of the earlier nightly check failures.

Model: gpt-6.1-sol. Harness: Codex in T3 Code.

Closes #13977

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: Path: .coderabbit.config.ts
• Review profile: CHILL
• Plan: Team
• Run ID: 6354d083-41dc-4d51-ada6-fe5c54081098

📥 Commits

Reviewing files that changed from the base of the PR and between d64de0a and 1c50504.

📒 Files selected for processing (2)

• apps/desktop/src/updates/DesktopUpdates.test.ts
• apps/desktop/src/updates/DesktopUpdates.ts

Included review availability: This review used your included allowance. Your plan provides up to 10 included reviews per hour; 1 remain after this review.

📝 Walkthrough

Walkthrough

Desktop updater failures now produce bounded, redacted cause summaries in logs. The summary helper handles nested causes, sensitive content, long values, cyclic causes, and unreadable error properties. Tests cover the helper and its use in updater logs.

Changes

Update error diagnostics

Layer / File(s)	Summary
Summarize and redact error causes apps/desktop/src/updates/DesktopUpdates.ts, apps/desktop/src/updates/DesktopUpdates.test.ts	Adds describeUpdateErrorCause to summarize causes with depth and length limits, redact sensitive content, and return a fallback when summarization throws. Tests cover nested causes, redaction, limits, cyclic causes, and unreadable properties.
Use summaries in updater logs apps/desktop/src/updates/DesktopUpdates.ts, apps/desktop/src/updates/DesktopUpdates.test.ts	Updater failure and warning logs now use cause summaries across checks, downloads, installs, pollers, and events. Tests check logged error details, redaction, and update state.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix · Severity of issue fixed: Low

Suggested reviewers: juliusmarminge

Merge Risk: ⚪ Minimal · up to 1c505

This change adds bounded, redacted cause details to desktop updater logs and leaves user-facing messages generic. No concrete merge-blocking risk was found.

Pre-merge checks · 4

Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check		Direct issue #13977 requires updater failure logs to record the underlying cause instead of only a fixed message, error tag, and channel. DesktopUpdates.ts adds describeUpdateErrorCause and includ…
Out of Scope Changes check		The reviewed changes are limited to apps/desktop updater logging and its tests. The formatter and test coverage directly support issue #13977. The changes add no settings, workflow, or unrelated use…
Title check		The title clearly identifies the desktop updater scope and the main change: preserving failure causes in diagnostics.
Description check		The description includes the required Problem, Change, Scope and approval, and Verification sections. It explains the focused fix, linked issue, test results, limitations, and agent details.

✨ Finishing Touches

📝 Generate docstrings

• Commit to this branch
• Create a new PR

🧪 Generate unit tests (beta)

• Commit to this branch
• Create a new PR

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

_{Comment @coderabbitai help to get the list of available commands.}

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — The PR is a focused updater diagnostics fix with bounded tests and unchanged update behavior, but it changes production logging and introduces handling for URLs, credentials, headers, and response-derived error content. Human validation is warranted for the sensitive-data redaction and logging behavior.

^{You can add or adjust custom eligibility rules. Learn more.}

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	5.0 KiB	5.0 KiB	0 B (0.0%)	6.8 KiB	✅
Codex	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Codex	Live turn WebSocket wire	1.2 KiB	1.2 KiB	0 B (0.0%)	2.0 KiB	✅
Codex	Live turn WebSocket decoded	20.9 KiB	20.9 KiB	0 B (0.0%)	29.3 KiB	✅
Codex	Live turn messages	2	2	0 (0.0%)	8	✅
Claude	Total thread wire	5.0 KiB	5.0 KiB	+24 B (+0.5%)	6.8 KiB	✅
Claude	Thread snapshot wire	3.8 KiB	3.8 KiB	0 B (0.0%)	4.9 KiB	✅
Claude	Live turn WebSocket wire	1.2 KiB	1.2 KiB	+24 B (+2.0%)	2.0 KiB	✅
Claude	Live turn WebSocket decoded	21.2 KiB	21.2 KiB	+41 B (+0.2%)	29.3 KiB	✅
Claude	Live turn messages	1	2	+1 (+100.0%)	8	✅

Baseline: b03534f · PR result: 1c50504 · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 108.5 KiB
• Claude decoded thread snapshot: 108.8 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.