feat(im): support Markdown image rendering in post content

[liujiashu-shiro]

Summary

Leverage underlying URL compatibility and remove redundant URL conversion logic to simplify the Markdown-to-Post element processing pipeline. Also add documentation for sending Markdown images, and align image handling guidance with actual runtime behavior.

Changes

• Remove buildPostElements, buildPostElementNodes, scanPostToken, scanBareURLToken, scanMarkdownLinkToken, scanBalancedParenToken, trimBareURLToken, appendMDPostNode, marshalJSONNoEscape, marshalStringNoEscape and related constants
• Revert buildSingleMDPost / buildSegmentedPost to single {"tag":"md"} serialization
• Replace marshalJSONNoEscape with standard json.Marshal
• Remove corresponding unit tests
• Add Markdown image instructions in lark-im-messages-send.md and lark-im-messages-reply.md
• Align Markdown image documentation with runtime behavior: clarify that img_xxx keys are the most reliable input, local paths are not supported, and remote URLs are auto-resolved at runtime (removed with a warning on failure); recommend pre-uploading via images.create for reliability

Test Plan

• Unit tests pass (go test ./shortcuts/im/)
• Verify lark im send --markdown with bare URLs renders correctly
• Verify sending images via Markdown image syntax displays properly

Summary by CodeRabbit

• Bug Fixes
  • Markdown content is now serialized and sent as single markdown blocks, preserving original markdown and changing how special characters are escaped; bare URLs and markdown links are no longer split into separate elements.
• Documentation
  • Updated Markdown image guidance: local file paths in Markdown are not supported; pre-upload via images.create is recommended; remote URLs may be auto-downloaded/uploaded and can be removed on failure; added examples and common-mistakes notes.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 56c30dea-9692-4187-817f-2b540db04b1d

📥 Commits

Reviewing files that changed from the base of the PR and between ec827b6 and 12f6fb9.

📒 Files selected for processing (2)

• shortcuts/im/helpers.go
• shortcuts/im/helpers_test.go

💤 Files with no reviewable changes (2)

• shortcuts/im/helpers_test.go
• shortcuts/im/helpers.go

---

📝 Walkthrough

Walkthrough

This PR consolidates Feishu markdown wrapping to emit single md nodes via standard json.Marshal, removes inline tokenization/link-splitting helpers, updates tests to the plain-markdown case, and clarifies --markdown image constraints (prefer pre-uploaded img_xxx, no local-path support, remote URLs may be auto-resolved).

Changes

Markdown wrapping simplification and image documentation

Layer / File(s)	Summary
Markdown wrapping simplification shortcuts/im/helpers.go	Replaces custom no-escape JSON marshaling with json.Marshal, consolidates segmented post construction from multi-element decomposition to single md elements, and removes tokenization/splitting helpers for URL and code-block preservation.
Test validation for plain markdown wrapping shortcuts/im/helpers_test.go	Rewrites TestWrapMarkdownAsPost to validate only the simplified plain markdown wrapping case, removing prior sub-tests for URL-to-link transformation and code-block URL preservation.
Image constraint documentation for messages-reply and messages-send skills/lark-im/references/lark-im-messages-reply.md, skills/lark-im/references/lark-im-messages-send.md	Clarifies markdown image handling across both skill references: recommends pre-uploaded img_xxx keys, states local file paths in markdown syntax are not supported, notes remote URLs may be auto-downloaded/uploaded at runtime with removal on failure, and adds examples plus common-mistake warnings.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• larksuite/cli#206: Both PRs modify shortcuts/im/helpers.go markdown-to-Feishu post wrapping (wrapMarkdownAsPost), with this PR consolidating to single md elements via standard json.Marshal, whereas PR #206 tokenizes into mixed md/a elements with no-escape marshaling.
• larksuite/cli#338: Both PRs modify shortcuts/im/helpers.go's markdown-to-Feishu wrapping pipeline (e.g., wrapMarkdownAsPost and content builders), with this PR removing tokenization/splitting behavior compared to the segmentation refactoring in #338.

Suggested labels

domain/im, size/L

Suggested reviewers

• YangJunzhou-01
• haozhenghua-code
• liangshuo-1

Poem

🐰 I wrap up markdown neat and slight,
One md node now, no split in sight,
Upload your pics before you send,
Local paths won't find a friend,
Simpler posts hop on through the night.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 12.50% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: adding support for Markdown image rendering in post content, which is the primary feature objective.
Description check	✅ Passed	The PR description includes all required sections from the template: Summary, Changes (detailed list), and Test Plan (with completed checkboxes). No required sections are missing.
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.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ 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 feat/markdown_image

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

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

[github-actions]

🚀 PR Preview Install Guide

🧰 CLI update

npm i -g https://pkg.pr.new/larksuite/cli/@larksuite/cli@12f6fb9b1890517543baf3f240bc10bcd604a7d0

🧩 Skill update

npx skills add larksuite/cli#feat/markdown_image -y -g

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 67.59%. Comparing base (56749e7) to head (12f6fb9).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #893      +/-   ##
==========================================
- Coverage   67.61%   67.59%   -0.03%     
==========================================
  Files         575      575              
  Lines       54347    54244     -103     
==========================================
- Hits        36747    36664      -83     
+ Misses      14555    14543      -12     
+ Partials     3045     3037       -8     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.