Windows: Large diffs fail due to 32KB CreateProcess command-line limit

[evgspacdmy]

Problem

On Windows, roborev review fails on large commits because the diff + prompt is passed as command-line arguments to the agent subprocess. Windows CreateProcess has a hard 32,766 character limit on the command line.

This means any commit with a diff exceeding ~30KB (accounting for the prompt template) will fail with an error like:

The command line is too long

Environment

• Windows 11 (10.0.26100)
• roborev v0.31.1
• Agent: opencode (but affects any agent)

Expected Behavior

Large diffs should be passed to the agent via stdin or a temporary file, not as command-line arguments.

Suggested Fix

Instead of:

agent.exe "Review this diff: <entire diff here>"

Use stdin piping:

echo <diff> | agent.exe "Review the diff from stdin"

Or a temp file:

agent.exe --input /tmp/roborev-diff-XXXX.txt "Review the diff"

Workaround

Using review_reasoning = "fast" reduces prompt size, but this is a band-aid. The fundamental issue is that diffs should not be passed via command-line arguments on any OS (Linux has a similar but higher limit at ~2MB via ARG_MAX).

[wesm]

I believed this was already addressed but evidently not! Thanks for reporting. Will fix