#21868: fix: qmd search/vsearch silently return empty with multiple -c collection flags (#21865)

## Problem Fixes #21865 `memory_search` always returns `{ results: [], provider: "qmd" }` for agents with 2+ collections configured. No error is surfaced; agents silently behave as if memory is blank. ### Root cause When `searchMode` is `"search"` or `"vsearch"` (the default), `search()` passes all managed collection names as simultaneous `-c` flags: ``` qmd search "query" --json -n 5 -c col1 -c col2 -c col3 -c col4 -c col5 -c col6 ``` QMD 1.0.x returns empty results (exit 0, no error) when multiple `-c` flags are passed to `search`/`vsearch`. Because there's no exception thrown, the existing `isUnsupportedQmdOptionError` fallback never fires. The existing `runQueryAcrossCollections()` workaround correctly handles this by iterating each collection separately, but it was only used for `searchMode: "query"`. ### Reproduction ```bash # Silently returns empty: qmd search "test" --json -n 5 -c col1 -c col2 -c col3 -c col4 -c col5 -c col6 # → No results found # Works (single -c per call): qmd search "test" --json -n 5 -c col1 # → results ✅ ``` ## Fix Extend the multi-collection workaround to **all** search modes, not just `"query"`. When multiple collections are configured, `runQueryAcrossCollections()` is always used — one call per collection, results merged by best score per doc. `runQueryAcrossCollections()` gains an optional `searchMode` parameter (default `"query"`) so the configured mode is preserved. A single-collection search still uses the direct `-c` path since that works correctly. ## Changes - `src/memory/qmd-manager.ts` - `search()`: condition `qmdSearchCommand === "query" && collectionNames.length > 1` → `collectionNames.length > 1` - `runQueryAcrossCollections()`: add optional `searchMode` param (default `"query"`), use it in `buildSearchArgs` - Catch block simplified: multi-collection branch removed (now unreachable); single-collection fallback retained ## Testing Verified locally on OpenClaw 2026.2.17 / QMD 1.0.6 / qmd-cli 1.1.0: - With `searchMode: "search"` (default) + 6 collections: `memory_search` now returns results ✅ - With `searchMode: "query"` + 6 collections: unchanged, still works ✅ - With `searchMode: "vsearch"` + 6 collections: now works (same fix applies) ✅ - Single collection: unchanged, direct `-c` path still used ✅ Workaround (while awaiting merge): set `memory.qmd.searchMode: "query"` in config. <!-- greptile_comment --> <h3>Greptile Summary</h3> extends multi-collection workaround from `query` mode to all search modes (`search`, `vsearch`) to fix silent empty results when agents have 2+ collections configured **Key improvement:** - main search path now correctly routes all multi-collection searches through `runQueryAcrossCollections` regardless of search mode, preventing the silent failure from passing multiple `-c` flags to qmd 1.0.x **Issue found:** - error fallback path (lines 429-434) doesn't properly handle multiple collections - when `runQueryAcrossCollections` throws an error, the fallback builds query args with multiple `-c` flags, recreating the exact bug this PR fixes. the old multi-collection branch in the catch block should be restored. <h3>Confidence Score: 2/5</h3> - contains logic error in error handling that could recreate the bug being fixed - while the main fix correctly routes multi-collection searches through the workaround, the error fallback path has a logic bug that can still trigger the silent failure with multiple `-c` flags when the first collection attempt fails. this significantly undermines the fix's effectiveness in edge cases. - `src/memory/qmd-manager.ts` lines 429-434 need correction to properly handle multi-collection fallback _{Last reviewed commit: 7c89cfc} <!-- greptile_other_comments_section --> _{(2/5) Greptile learns from your feedback when you react with thumbs up/down!} <!-- /greptile_comment -->