unused can run for minutes without output

[Widthdom]

Summary

unused can run for a long time with no progress, partial output, or bounded completion signal, even when a small --limit is provided.

Observed

During dogfooding on the current repository, I ran:

dotnet ./src/CodeIndex/bin/Debug/net8.0/cdidx.dll unused --path src/ --exclude-tests --json --limit 50

The command produced no output after more than 90 seconds. I eventually identified the running process and killed it:

• PID: 9124
• command: dotnet ./src/CodeIndex/bin/Debug/net8.0/cdidx.dll unused --path src/ --exclude-tests --json --limit 50
• exit after kill: 143

Expected

For expensive analysis commands, one or more of these should be true:

• --limit should materially bound the work;
• JSON mode should offer progress or a clear slow-query/profile path;
• the command should emit a diagnostic explaining what phase is expensive;
• the implementation should avoid unbounded joins/scans where possible.

Impact

Agents and users cannot distinguish a legitimate long-running analysis from a hang. This interrupts code-search-driven audits and makes unused hard to trust in automation.

[Widthdom]

Work started on branch fix-issue2811.