fix(feishu): route markdown tables through post+tag:md instead of force-text

[YzFrocket]

Summary

Feishu's post-type md element renders the full GFM surface today, including tables. The historic _MARKDOWN_TABLE_RE workaround in _build_outbound_payload predates that and force-downgrades the entire message to msg_type: text whenever a GFM table appears. That side-effect strips formatting from every other markdown element in the same message (headings, bold, code blocks, lists, quotes), so mixed-content replies render as raw markdown source on the client.

This PR routes table-bearing markdown through post + tag: md like every other markdown shape, removing the force-text branch.

Repro before this fix

Send any Feishu message that mixes a markdown table with other markdown:

## Some heading
Some **bold** prose.

| col1 | col2 |
|------|------|
| a    | b    |

Trailing text with `inline code`.

Result on the Feishu client: the whole message arrives as raw text — ##, **, |, fences all visible as characters. Same content without the table renders correctly as a post.

Root cause

plugins/platforms/feishu/adapter.py::FeishuAdapter._build_outbound_payload (line 4377 on main):

def _build_outbound_payload(self, content):
    if _MARKDOWN_TABLE_RE.search(content):
        # Force plain text for anything that looks like a markdown table.
        return "text", json.dumps({"text": content}, ensure_ascii=False)
    if _MARKDOWN_HINT_RE.search(content):
        return "post", _build_markdown_post_payload(content)
    return "text", json.dumps({"text": content}, ensure_ascii=False)

The first branch fires whenever the regex matches ^|...|\n|---|... anywhere in the message and demotes the whole reply to plain text — losing all other markdown for the sake of "rescuing" the table.

The original justification (Feishu's md tag didn't render tables) is no longer accurate: the official create_json doc lists tables under the tag: md example, and empirical testing on current Feishu clients (verified in the linked issue #27529) confirms tables render correctly inside post + md.

Fix

Send tables through post + tag: md like every other markdown shape:

def _build_outbound_payload(self, content):
    if _MARKDOWN_TABLE_RE.search(content) or _MARKDOWN_HINT_RE.search(content):
        return "post", _build_markdown_post_payload(content)
    return "text", json.dumps({"text": content}, ensure_ascii=False)

A pre-emptive text fallback is no longer needed: the send loop already handles a rejected post payload via _POST_CONTENT_INVALID_RE and degrades to plain text on both API exception and unsuccessful API response (existing code, _send_text_message around line 1801). So if Feishu ever regresses on table rendering inside posts, behaviour reverts to the current safety net automatically — but on success the receiver gets a properly-rendered post for the table and all surrounding markdown.

The detector _MARKDOWN_TABLE_RE itself is preserved (some metrics / logging paths may want to know a message contained a table). Only the routing changes. The stale comment block above the regex is updated to record the new contract.

Test Plan

• New: test_outbound_payload_routes_markdown_tables_to_post_md pins the regression — a message containing a table plus heading + bold + trailing prose is emitted as a single post+md payload, not downgraded to text.
• New: test_outbound_payload_keeps_plain_text_for_non_markdown guards the second branch so the change doesn't accidentally widen the post path to plain-text content (which would cost a richer-rendering payload for nothing).
• Full tests/gateway/test_feishu.py suite — 207/207 passed.
• Existing fallback tests (test_send_falls_back_to_text_when_post_payload_is_rejected, test_send_falls_back_to_text_when_post_response_is_unsuccessful, test_edit_message_falls_back_to_text_when_post_update_is_rejected) still pass — confirms the post-rejection safety net is intact for tables now too.

References

• [feishu] Fix markdown table rendering: use post+tag:md instead of force-text workaround #27529 — proposes this exact fix (post + tag:md replaces force-text)
• [Feishu] Markdown tables not rendering in Feishu messages #9549 — original bug report on table rendering
• [feishu] Remove markdown table force-text workaround — Feishu now supports tables in post format #26658 — alternative proposal to remove the detector entirely
• Feishu API: 发送消息内容结构 — tag: md

Not closing #27529 / #9549 — leaving it to maintainers' judgement whether this PR addresses them in full.

[alt-glitch]

This was generated by AI during triage.

Related/competing: this is the latest entrant in the long-standing Feishu markdown-table rendering cluster — same post+tag:md mechanism as open #29552 and #33800 (canonical #26108 is closed). Note this PR targets the relocated adapter at plugins/platforms/feishu/adapter.py while the earlier PRs touched gateway/platforms/feishu.py. Not marking a duplicate — these compete on the same fix and a maintainer should pick one.

[teknium1]

Thanks for the focused Feishu fix. The functional direction is sound: current main still returns plain text for matching tables at plugins/platforms/feishu/adapter.py:4528, while Feishu’s current message-content documentation recommends post + md for GFM tables.

Problems

• The new detector comment says it is retained for logging/metrics, but _MARKDOWN_TABLE_RE has no logging or metrics consumer; its remaining use is outbound routing (plugins/platforms/feishu/adapter.py:158-160, 4528).

Suggested changes

• Describe the detector as selecting the post+md path for table-bearing content, rather than as a logging/metrics signal.

This is an automated hermes-sweeper review.

[teknium1]

The detector remains required by the routing condition below, but repository-wide search finds no logging or metrics consumer for it. Please remove that rationale and describe it as selecting the post+md route for table-bearing content.