[FR] Make it more obvious when ctags indexing fails

[dsabsay]

While setting up a dev environment, I misconfigured the CTAGS_COMMAND which resulted in zoekt being unable to index repositories. Unfortunately, the UI indicated that the indexing was completed successfully. When searching with e.g. sym:main (or any other symbol), 0 results were returned.

This is the error in the logs:

[worker] 2026-06-22T04:37:49.344Z debug: [zoekt] /Library/Developer/CommandLineTools/usr/bin/ctags: illegal option -- -
[worker] 2026-06-22T04:37:49.345Z debug: [zoekt] usage: ctags [-BFTaduwvx] [-f tagsfile] file ...
[worker] 2026-06-22T04:37:49.345Z debug: [zoekt] 2026/06/21 21:37:49 ignoring universal:ctags or scip: error: write |1: file already closed
[worker] 2026-06-22T04:37:49.345Z debug: [zoekt] 2026/06/21 21:37:49 symbol analysis finished for shard statistics: duration=0s symbols=0 bytes=146

I could imagine other scenarios in which ctags indexing might fail. Perhaps the entire index pass should be considered failed in that case? Or at least partially degraded? It's currently impossible to tell from the UI that anything with the indexing is broken.

[zsxh1990]

Picking this up! Plan:

1. Detect ctags failure signals (symbols=0, illegal option errors)
2. Surface degraded state in repo indexing status
3. Add UI warning when symbol indexing fails but text indexing succeeds

PR incoming.

[zsxh1990]

This is resolved by PR #1383 which adds ctags indexing failure detection. When ctags fails, the error is surfaced to the user instead of silently falling back.