fix(categories): treat blank regex rules as matching nothing everywhere

[TimeToBuildBob]

Fixes #382.

Root cause

The views don't agree on what a blank regex rule means:

• Server-categorized views (Category Sunburst, Timeline barchart, Top Categories) get $category from categorize() in the query. aw-core's Rule deliberately never matches an empty regex (aw_transform/classify.py: "also checks that the regex isn't an empty string (which would erroneously match everything)"), so those views ignore the category.
• Client-side views (Top Applications, Top Window Titles) color rows with matchString(), which compiles RegExp(''). That matches every string, so every app or title not claimed by a more specific rule lands in the blank-regex category.

aw-server-rust differs from aw-core here as well: its RegexRule::new("") compiles to a match-all regex.

The editor has refused empty patterns since 9f37315 (validateRegex('') === false). Blank rules still reach users through older stored settings and imported category files.

Fix

• hasMatchableRegex(c) in util/classes.ts is used by both matchString and classifyEvents, so client-side matching skips blank regexes the same way aw-core does.
• classes_for_query sends blank-regex rules as { type: 'none' }, so aw-server-rust and aw-server give the same result. The category still exists as a container, and its children match as before.

Tests

• classes.test.node.ts: with a blank-regex Work parent and a Work > Programming (vim) child, matchString/classifyEvents return Uncategorized for unrelated strings (master returned Work) and still return the child for vim.
• store/categories.test.node.ts: classes_for_query sends the blank rule as none and leaves real regex rules unchanged.

Ran locally: jest on the classes, categories store, categorization, queries and Sunburst suites (42 passed), tsc --noEmit is clean, and prettier passes. No .vue files changed.

[greptile-apps]

Confidence Score: 5/5

[Medium risk] Changes how blank regex rules are categorized.

The PR appears safe to merge.

Summary

The PR makes empty category regexes match nothing in client-side classification and sends them to server queries as none, while retaining child category rules.

• Adds regression tests for client matching and the query payload.
• No actionable issues were identified.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart LR
  A[Category rules] --> B{Empty regex?}
  B -- Yes --> C[Client: skip matching]
  B -- Yes --> D[Server query: send type none]
  B -- No --> E[Keep regex rule]
  E --> F[Client and server classification]

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_{Reviews (1) · Last reviewed commit: "fix(categories): treat blank regex rules..."}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 63.37%. Comparing base (45e9c41) to head (ad8139b).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1026      +/-   ##
==========================================
+ Coverage   63.30%   63.37%   +0.07%     
==========================================
  Files          52       52              
  Lines        3608     3607       -1     
  Branches      840      894      +54     
==========================================
+ Hits         2284     2286       +2     
+ Misses       1309     1306       -3     
  Partials       15       15              

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[TimeToBuildBob]

CI-green and mergeable (Greptile 5/5) — waiting only on a maintainer click.

This PR is ready to merge, but the bot has pull-only access to this repo and can't self-merge — surfacing it here so it isn't lost. The monitoring loop will stop re-flagging it now that this note is posted.

[TimeToBuildBob]

🤖 AI code review

Adds hasMatchableRegex() to util/classes.ts, which returns false for regex rules with an empty regex string. matchString and classifyEvents now filter categories through it so blank regexes never match client-side. classes_for_query converts blank-regex rules to { type: 'none' } before sending them to the server. Adds unit tests for both matching and the query getter.

Safe to merge — no P0/P1 findings

Confidence 5/5

✅ No findings. The diff looks correct to me on this pass.

Files changed (4) — the diff as I read it

• src/util/classes.ts — Adds hasMatchableRegex() and filters regex categories in matchString and classifyEvents so empty regexes are not compiled.
• src/stores/categories.ts — Imports hasMatchableRegex; classes_for_query now maps blank-regex rules to { type: 'none' }.
• test/unit/classes.test.node.ts — Adds test verifying a blank-regex parent does not match while its regex child still does.
• test/unit/store/categories.test.node.ts — Adds test for classes_for_query converting a blank-regex rule to type none.

_{Reviewed ad8139bd31d4 · openrouter/deepseek/deepseek-v4-flash-0731 · llm engine · 1031s · about this reviewer}

_{Maintainer commands}

_{@TimeToBuildBob review (own line) — fresh review · @TimeToBuildBob fix — a worker acts on the findings. Once per comment; 👀 = received.}