[deep-report] Make cacheMemoryDirFor return an error instead of panicking on invalid cache-memory ID #65083

Description

cacheMemoryDirFor (pkg/workflow/cache_config.go:37) panics on an invalid cache-memory ID instead of returning an error, forcing a string-returning API shape onto what is really a fallible operation. It's called from 8 sites across cache_memory.go and sandbox.go. Validation currently happens at parse time so the practical risk is low, but any future caller that skips that validation step (or a validation gap) turns into an uncaught panic rather than a handled error.

Expected Impact

Removes the last of the four reachable-panic sites flagged in this audit, making the cache-memory path consistent with the rest of the compiler's error-returning conventions.

Suggested Agent

GitHub Copilot coding agent — change cacheMemoryDirFor to return (string, error), update all 8 callers in cache_memory.go/sandbox.go to propagate the error, and update TestCacheMemoryDirFor_InvalidIDPanics (in cache_id_validation_test.go) to assert an error instead of a panic.

Estimated Effort

Quick (<1 hour)

Data Source

DeepReport Intelligence Briefing — 2026-10-02, sourced from Repository Quality Improvement Report #65022 ("Compiler Panic Containment"), Task 4.

Generated by 🔬 Deep Report · claude · agent · 212 AIC · ⌖ 7.99 AIC · ⊞ 7.3K · ◷

• expires on Oct 4, 2026, 10:42 AM UTC-08:00