fix(mcp): log the numeric auto_index_limit in autoindex.skip (#1466)

[rarepops]

Fixes #1466

Problem

When auto-indexing skips a repository because its tracked-file count exceeds auto_index_limit, the warning reports the name of the config key instead of the configured value:

level=warn msg=autoindex.skip reason=too_many_files files=2 limit=auto_index_limit

CBM_CONFIG_AUTO_INDEX_LIMIT is #defined as the string "auto_index_limit" in src/cli/cli.h, and it was being passed straight through as the value of the limit field:

cbm_log_warn("autoindex.skip", "reason",
             file_count >= 0 ? "too_many_files" : "unsafe_or_unavailable_path", "files",
             files, "limit", CBM_CONFIG_AUTO_INDEX_LIMIT);

The effective numeric limit was already in scope as file_limit, read a few lines earlier via cbm_config_get_int().

As the reporter noted, the malformed files field from v0.9.0 is already fixed on main; only the limit field remained.

Fix

Format file_limit into a buffer, mirroring exactly how the neighbouring files count is already handled:

char files[32];
char limit[32];
(void)snprintf(files, sizeof(files), "%d", file_count);
(void)snprintf(limit, sizeof(limit), "%d", file_limit);
cbm_log_warn("autoindex.skip", "reason",
             file_count >= 0 ? "too_many_files" : "unsafe_or_unavailable_path", "files",
             files, "limit", limit);

Output now matches the issue's expectation:

level=warn msg=autoindex.skip reason=too_many_files files=2 limit=1

Test

autoindex_skip_reports_numeric_limit_issue1466 in tests/test_mcp.c drives the real public entry point (initialize -> maybe_auto_index) against a fresh project holding more files than auto_index_limit, and captures the emitted warning through a log sink.

Reproduce-first, verified in both directions on the same tree:

	before the source fix	after
autoindex_skip_reports_numeric_limit_issue1466	FAIL tests/test_mcp.c:10637: strstr(warning, "limit=1") is NULL	PASS
mcp suite	203 passed, 1 failed, 6 skipped	204 passed, 0 failed, 6 skipped

The failure is not vacuous: the msg=autoindex.skip, reason=too_many_files and files=2 assertions all pass in the RED run, so the skip path is genuinely exercised and the log line is genuinely captured. Only the limit=1 assertion flips. The test also asserts the absence of limit=auto_index_limit, so a future regression that drops the value back to the key name fails loudly.

Verification

Run in a container mirroring the CI toolchain (Ubuntu 24.04 + gcc, ASan/UBSan build):

• mcp suite: 204 passed, 0 failed
• log, daemon, daemon_runtime, daemon_application (the suites covering the logging layer and the sibling auto-index admission path): 120 passed, 0 failed
• lint-format with clang-format-20: clean
• lint-cppcheck with cppcheck 2.20.0: clean

lint-no-suppress and lint-mem-ci are structurally unaffected: the diff adds no NOLINT, the only LINT_SRCS file touched is src/mcp/mcp.c (two stack buffers, no allocation), and no entry in scripts/lint-mem-whitelist.txt is pinned to maybe_auto_index, so no sha256 pin is invalidated.

Out of scope (possible follow-up)

While tracing this I noticed the daemon has a sibling warning at src/daemon/application.c that emits reason and files for the same condition but carries no limit key at all:

cbm_log_warn("daemon.autoindex.skipped", "project", project, "reason",
             tracked_files >= 0 ? "too_many_files" : "unsafe_or_unavailable_path", "files",
             files);

That is a different defect from #1466 (a missing field rather than a wrong one) and it is not what the issue reports, so I left it alone to keep this PR to one issue. Happy to open a separate issue or PR for it if you would like the two skip warnings to carry the same fields.

[github-actions]

Thanks for opening this — it has been seen, and it is queued.

This note is automated, but it is not a brush-off: it exists so you know where your PR stands instead of having to guess from silence.

Current review status: working through a backlog. 0.9.1-rc.1 is out, so the release freeze that held reviews is over — but it left a large queue of open pull requests behind it, and we are reading through them oldest-first. The background is in discussion #1144.

What that means for this PR, concretely:

• It will not be closed for inactivity. No stale bot touches pull requests here.
• It may still sit a while before a human reads it. That is on us, not on you.
• Older PRs are read first, so a recent one is not being skipped — it is behind a queue.

Things that will genuinely speed it up whenever review does happen:

• Keep it rebased on main — the tree is moving quickly right now, and a conflicting branch cannot be reviewed as the diff you intended.
• Get CI green, or say which failures you believe are pre-existing.
• Keep the change to one claim. Bundled features and refactors get split before they get merged, which costs you a round trip.
• Every commit needs a sign-off (git commit -s) — CI enforces DCO.

If this fixes a bug, a reproduction we can run is worth more than a description of the symptom.

Thanks for contributing, and sorry in advance for the wait.

[DeusData]

Thank you for keeping the sibling daemon warning out of this focused fix. I checked current main and your distinction is correct: the MCP warning emits the configuration key name where the value should be, while daemon.autoindex.skipped omits the limit field entirely.

Please open a separate focused issue for the daemon-log parity gap and link it here. This PR should remain limited to #1466. The current fix and binding log-sink test are grounded and have been labeled for review. Our queue is full, so detailed review may take a little time. Thank you for calling out the adjacent defect without bundling it.

[rarepops]

Opened #1818 as requested and kept it scoped to the daemon-log parity gap.

The focused daemon_application suite reproduces the current warning without a limit field, while all 49 tests pass. This remains separate from the MCP-side fix in this PR.