Fix duplicate slash alias crash

[giattijunior]

Fix duplicate slash alias crash when agent catalog includes /compact

Summary

The renderer crashed when the backend command catalog exposed /compact both as:

• a standalone command in pairs
• an alias mapping compact -> compress in canon

createSlashCatalog() registered the command first, then registerAlias() threw Duplicate slash command alias: /compact, which broke the Chat screen on connection.

Fix

Ignore duplicate alias registrations when the canonical command is already present instead of throwing.

Validation

• Added a regression test for pairs: /compact, /compress plus canon: compact -> compress
• Ran:

npm test -- src/renderer/src/screens/Chat/slash/commandCatalog.test.ts

Result: 1 passed, 4 passed

[greptile-apps]

Greptile Summary

This PR fixes a renderer crash that occurred when the backend command catalog exposed the same name (e.g., /compact) as both a standalone command in pairs and as an alias key in canon. The fix changes registerAlias to silently return instead of throwing when the alias key is already registered.

• commandCatalog.ts: registerAlias now returns early instead of throwing on duplicate alias key, preventing the crash for backend catalogs that emit contradictory pairs/canon entries for the same name.
• commandCatalog.test.ts: Adds a regression test that faithfully reproduces the /compact+/compress scenario and asserts both commands resolve independently after the fix.

Confidence Score: 4/5

The change is safe to merge; it eliminates a real crash with minimal surface area, and the new test directly reproduces the failure scenario.

The crash fix is correct and well-scoped. Two minor concerns: (1) the silent return applies to both command-vs-alias and alias-vs-alias conflicts, so if two independent alias sources ever map the same key to different targets, the second one loses without any observable signal; (2) agentCommandsFromCatalog still emits the contradictory alias into its output rather than filtering it at the source, so the deduplication logic is split across two functions. Neither is a present defect — just edge-case hardening worth revisiting.

The registerAlias function in commandCatalog.ts is the place to revisit if alias-vs-alias conflicts with different targets become possible.

Important Files Changed

Filename	Overview
src/renderer/src/screens/Chat/slash/commandCatalog.ts	Changes registerAlias to silently return (instead of throw) when the alias key is already present; fixes the crash but the silent-drop applies to alias-vs-alias conflicts too, not just command-vs-alias ones
src/renderer/src/screens/Chat/slash/commandCatalog.test.ts	Adds a regression test that exercises pairs: /compact, /compress + canon: compact → compress; accurately reproduces the crash scenario and verifies both commands resolve correctly after the fix

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
    participant B as Backend Catalog
    participant A as agentCommandsFromCatalog
    participant C as createSlashCatalog
    participant R as registerAlias

    B->>A: "{ pairs: [[/compact,...],[/compress,...]], canon: {compact: compress} }"
    A->>A: "Build seen = {compact, compress}"
    A->>A: "Emit alias compact→compress (seen.has(compress) = true)"
    A-->>C: "{ commands: [compact, compress], aliases: {compact: compress} }"

    C->>R: registerCommand(compact) ✅
    C->>R: registerCommand(compress) ✅
    C->>R: registerAlias(compact, compress)
    Note over R: byName.has(compact) = true
    R-->>C: return (silent, was: throw) ✅ fix

    Note over C: /compact → compact cmd
    Note over C: /compress → compress cmd

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sequenceDiagram
    participant B as Backend Catalog
    participant A as agentCommandsFromCatalog
    participant C as createSlashCatalog
    participant R as registerAlias

    B->>A: "{ pairs: [[/compact,...],[/compress,...]], canon: {compact: compress} }"
    A->>A: "Build seen = {compact, compress}"
    A->>A: "Emit alias compact→compress (seen.has(compress) = true)"
    A-->>C: "{ commands: [compact, compress], aliases: {compact: compress} }"

    C->>R: registerCommand(compact) ✅
    C->>R: registerCommand(compress) ✅
    C->>R: registerAlias(compact, compress)
    Note over R: byName.has(compact) = true
    R-->>C: return (silent, was: throw) ✅ fix

    Note over C: /compact → compact cmd
    Note over C: /compress → compress cmd

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Comments Outside Diff (1)

1. src/renderer/src/screens/Chat/slash/commandCatalog.ts, line 120-124 (link)

   agentCommandsFromCatalog does not pre-filter command-shadowed aliases

   When a canon entry's alias key (compact) is already in seen as a canonical command, agentCommandsFromCatalog still emits it into the returned aliases record. The duplicate is only suppressed later inside registerAlias. Adding || seen.has(alias) to the continue-condition on line 123 would prevent the contradictory alias from ever leaving this function, making the intent self-documenting and keeping registerAlias a pure invariant-checker rather than a policy-applier. As-is, the fix works but the deduplication logic is split across two functions that are hard to reason about together.

   Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!

_{Reviews (1): Last reviewed commit: "Fix duplicate slash alias crash" | Re-trigger Greptile}

[greptile-apps]

Silent alias-vs-alias conflict silently drops second mapping

The early return now fires both when the alias key collides with a canonical command (the intended fix) and when it collides with an already-registered alias pointing to a different target. In the second case — e.g., if agent commands and desktop commands each define "/r" → different targets — the second registration silently loses with no observable feedback. The upstream agentCommandsFromCatalog protects against this today because Object.entries de-dupes object keys, but future callers that supply aliases from two independent sources could hit it and get the wrong resolution without any warning. A dev-mode console.warn on the aliases.has(aliasKey) branch would make this detectable.

[fathah]

Thanks for tracking this down and for the regression test — the diagnosis of the /compact pairs-vs-canon collision was exactly right.

This has since been fixed on main by #808, which resolves the same collision one layer earlier: agentCommandsFromCatalog now drops a canon alias whose name is already a first-class pairs command, so the reconciled catalog is self-consistent before it ever reaches createSlashCatalog. Your repro scenario (pairs: /compact, /compress + canon: compact → compress) is covered by a regression test there.

We deliberately kept the fix out of registerAlias: its throw-on-duplicate is intentional validation for genuine desktop-authoring conflicts (two in-repo commands claiming the same name), and silently returning would mask those at startup. The design rule we've settled on — also applied in #818 for the related backend-command-vs-desktop-alias case — is that backend catalog data is untrusted runtime input and gets sanitized at the reconciliation layer, while createSlashCatalog's throw stays strict for in-repo authoring mistakes.

Closing as superseded by #808. Thanks again for the report and the clean repro — it helped confirm the fix covers this exact case.