fix: advertise 100MB limit, files that exceed that limit show a message

[highesttt]

No description provided.

[linear-code]

PLAT-38237

[indent-zero]

PR Summary

Advertises a 100 MB per-file limit to Matrix clients via the bridge File capabilities and, on the receive path, replaces the failed Matrix upload for over-limit LINE media with a friendly MsgNotice across every supported media type. Follow-up commit generalized the guard to image/video/audio/file and added a metadata short-circuit so oversized payloads are never downloaded.

• Adds handlers.BeeperMaxFileSize (100 MiB) and sets MaxSize on MsgImage, MsgFile, MsgVideo, MsgAudio, CapMsgVoice in LineClient.GetCapabilities.
• Bumps GetBridgeInfoVersion capabilities 2 → 3 so clients re-fetch the updated caps.
• New pkg/connector/handlers/media_size.go exposes oversizedMediaNoticeFromMetadata (early FILE_SIZE check with a 32-byte E2EE HMAC tolerance) and oversizedMediaNotice (post-download authoritative check), used by all Convert{File,Image,Video,Audio} handlers.
• Adds unit tests for the notice generator, per-handler short-circuit behavior, and boundary/invalid FILE_SIZE fallback cases.
• Updates reaction_test.go to expect the new 1/3 version pair.

Issues

All clear! No issues remaining. 🎉

3 issues already resolved

• Notice body has an ungrammatical comma: "Open LINE, to view it." should be "Open LINE to view it." (fixed by commit c3ec1fa)
• Oversize notice is only wired into ConvertFile, but MaxSize: 100MB is advertised for MsgImage, MsgVideo, MsgAudio, and CapMsgVoice too — LINE media of those types >100 MB still hits intent.UploadMedia and fails without a user-facing message. (fixed by commit c3ec1fa)
• Oversize check runs after the full download and decrypt, wasting bandwidth/memory/CPU on files we then discard — data.ContentMetadata["FILE_SIZE"] (already populated on the send path) could short-circuit before hitting OBS. (fixed by commit c3ec1fa)

CI Checks

All CI checks passed on commit c3ec1fa.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: edfa6e1a-44cf-4b83-9900-f29e7f4c17a8

📥 Commits

Reviewing files that changed from the base of the PR and between c3d36ba and c3ec1fa.

📒 Files selected for processing (6)

• pkg/connector/handlers/audio.go
• pkg/connector/handlers/file.go
• pkg/connector/handlers/image.go
• pkg/connector/handlers/media_size.go
• pkg/connector/handlers/media_size_test.go
• pkg/connector/handlers/video.go

📜 Recent review details

⏰ Context from checks skipped due to timeout. (4)

• GitHub Check: Lint with 1.25
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🧰 Additional context used

📓 Path-based instructions (2)

**/*.go

📄 CodeRabbit inference engine (AGENTS.md)

**/*.go: Use go fmt for code formatting across all Go files
Use goimports with -local "github.com/highesttt/matrix-line-messenger" flag to group project-local imports correctly
Use zerolog for logging throughout the codebase
Do not use Msgf in logging; use Msg with structured fields instead
Use Stringer interface where applicable in Go code

Files:

• pkg/connector/handlers/media_size_test.go
• pkg/connector/handlers/image.go
• pkg/connector/handlers/audio.go
• pkg/connector/handlers/media_size.go
• pkg/connector/handlers/file.go
• pkg/connector/handlers/video.go

**/!(ltsm)/**/*.go

📄 CodeRabbit inference engine (AGENTS.md)

**/!(ltsm)/**/*.go: Run staticcheck on all Go files excluding pkg/ltsm package (transpiled WASM code)
Run go vet on all Go files excluding pkg/ltsm package (transpiled WASM code)

Files:

• pkg/connector/handlers/media_size_test.go
• pkg/connector/handlers/image.go
• pkg/connector/handlers/audio.go
• pkg/connector/handlers/media_size.go
• pkg/connector/handlers/file.go
• pkg/connector/handlers/video.go

🔇 Additional comments (7)

pkg/connector/handlers/media_size.go (2)

11-48: LGTM!

---

3-9: 📐 Maintainability & Code Quality

Resolve the unavailable checks before approval. gofmt passes. goimports and staticcheck are unavailable. go vet fails in maunium.net/go/mautrix because sqlite3.Error and sqlite3.ErrCorrupt are undefined.

pkg/connector/handlers/audio.go (1)

18-21: LGTM!

Also applies to: 102-105

pkg/connector/handlers/file.go (1)

17-20: LGTM!

Also applies to: 96-99

pkg/connector/handlers/image.go (1)

18-21: LGTM!

Also applies to: 102-105

pkg/connector/handlers/video.go (1)

19-22: LGTM!

Also applies to: 116-119

pkg/connector/handlers/media_size_test.go (1)

1-108: LGTM!

---

📝 Walkthrough

Summary by CodeRabbit

• New Features

  • Added support for reporting file-size capabilities for image, file, video, audio, and voice messages.
  • Added a 100 MiB maximum media size limit.

• Bug Fixes

  • Oversized media is now detected before or after download, preventing unnecessary processing and uploads.
  • Users receive a notice when media exceeds the allowed size.

Walkthrough

The connector adds a shared 100 MiB media limit. Handlers reject oversized media before download or upload, capabilities advertise the limit, and the capability version increases to 3.

Changes

File-size capability and enforcement

Layer / File(s)	Summary
Oversized file notice flow pkg/connector/handlers/media_size.go, pkg/connector/handlers/*, pkg/connector/handlers/media_size_test.go	Media handlers validate metadata before download and downloaded or decrypted size before Matrix upload. Oversized media returns a Matrix notice. Tests cover limits, metadata parsing, encrypted overhead, and short-circuiting.
Capability advertisement and version pkg/connector/userinfo.go, pkg/connector/connector.go, pkg/connector/*_test.go	Supported media capabilities advertise the shared 100 MiB limit. The capability version and related tests now use version 3.

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

Sequence Diagram(s)

sequenceDiagram
  participant LineMetadata
  participant MediaHandler
  participant Matrix
  LineMetadata->>MediaHandler: FILE_SIZE metadata
  MediaHandler->>MediaHandler: compare with BeeperMaxFileSize
  MediaHandler->>LineMetadata: download and decrypt allowed media
  MediaHandler->>MediaHandler: check downloaded size
  MediaHandler->>Matrix: upload media or send oversized-media notice

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Possibly related PRs

• beeper/line#213: Both PRs modify GetBridgeInfoVersion and its capability-version test.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Description check	❓ Inconclusive	No pull request description was provided, so its relevance to the changeset cannot be assessed.	Add a concise description that explains the advertised 100 MB limit and the handling of oversized media.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the 100 MB limit announcement and oversized-file handling implemented by the pull request.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch highest/plat-38237

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