Unify logging: replace mixed eprintln! with structured tracing

[codesoda]

Summary

Structured tracing (tracing::info!, tracing::warn!, tracing::error!) is used in most modules, but claude_code.rs, main.rs, and update.rs emit diagnostic output via raw eprintln!, bypassing the tracing subscriber. Some events are double-logged. The entire update.rs (672 lines) has zero tracing calls.

Severity: S2 (Medium) | Confidence: 0.95 | Blast radius: Low

Technical Details

Double-logging (same event, two sinks):

// src/main.rs:357-358
tracing::error!("failed to write report: {e}");
eprintln!("WARNING: failed to write report: {e}");  // same event!

Verbose output bypassing tracing:

// src/claude_code.rs:174, 184, 229, 237, 238
eprintln!("[verbose] ...");  // should be tracing::debug!

Entire module invisible to structured logs:

• src/update.rs — 672 lines, zero tracing:: calls, all output via eprintln!
• Lines 375, 391, 559 — error/progress output that never appears in the log file created by diagnostics::init_tracing

Impact:

• Post-mortem debugging of update failures requires reproducing the issue (no log trail)
• Verbose provider output is invisible to the tracing subscriber and any log aggregation
• The double-logging in main.rs produces duplicate entries in different formats

Proposed Fix

1. update.rs: Replace all eprintln! calls with appropriate tracing::info! / tracing::warn! / tracing::error! calls (~10 replacements)
2. claude_code.rs: Replace verbose eprintln!("[verbose]...") with tracing::debug! (lines 174, 184, 229, 237, 238)
3. main.rs: Remove duplicate eprintln! calls where tracing::error! is already used (line 358). Keep eprintln! only for pre-tracing-init errors (acceptable fallback)

Estimated effort: ~3 hours

Related

• Part of refactor Bundle 5: Unified Observability

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🔍 Found by vibe-code-audit — automated codebase audit skill for Claude Code.