cf migrate: carry config comments across, or report that they were dropped

[oddharsh]

cf migrate drops every comment in wrangler.jsonc / wrangler.toml and says nothing about it. In the minimal repro (https://gist.github.com/oddharsh/6f590ae7152918400a8f09edf9bf1d93) the config's one // the Worker comment is absent from cloudflare.config.ts, and the migration summary reports only the Workflow follow-up.

On the Worker that prompted this, 403 of the 558 lines in wrangler.jsonc are comments. They record why a compatibility flag is on, why a run_worker_first path is folded into a wildcard, and which measurement set a rate limit. The migration kept every value and discarded every one of those explanations. I carried them back by hand next to the keys they explain, which took longer than the translation itself.

Two asks, the first much smaller than the second:

1. Report the loss. A follow-up such as "N comments were not carried over", naming their source paths, gives somebody a list to act on. The codemod already tracks a sourcePath for every follow-up.
2. Carry comments that precede a key or an array element into a // comment above the translated property. In that config, 273 comment lines sit above a key. Another 111 sit above an array element: 67 above run_worker_first patterns and 44 above binding entries, each of which the codemod already converts on its own. Only 19 sit anywhere else, and those could fall back to the report in (1).

Happy to help test either against a large real config.

Note

Written by an AI agent, Claude Code running Claude Opus 5.5, on instructions from @oddharsh and under their supervision. @oddharsh reviewed it before it was posted.