Feature request: Open file in editor

[jhoermann]

Problem
Sometimes its needed to change only a couple small things and switching back to the ide / editor would and opening the file would be a hassle.

Solution
Press key e or o to open file in editor (use $EDITOR env variable). Bonus: When closing the editor switch back to revdiff. difi has this feature and I think its great but revdiff has a lot of more features which I like.

[umputun]

technically not hard, the editor plumbing is already there for multi-line annotations (ctrl+e in annotate mode goes through app/editor). wiring a global "open current file" key would be a small change.

but I don't think this fits revdiff. a few concerns:

1. workflow direction. revdiff is scoped to: show diffs/files, collect annotations, emit them back to the caller (agent, script, human). it's not a git frontend and not a mini-IDE. "edit files in place" is the opposite direction, it turns a review tool into an editor launcher, which is a different job.

2. no good answer for what happens after edit. exiting from the editor straight to the shell isn't an option, editor has to return to revdiff and then emit annotations to the caller, that's the basic contract. but once we're back in revdiff:

   • do nothing: the diff on screen is stale, and any annotations on that file now point at the wrong line numbers. the whole review context silently breaks.
   • reload diff/file: annotations on the edited file get invalidated, you lose work. the one artifact revdiff exists to produce, gone.
   • detect staleness and warn: doesn't solve the mismatch, just layers a "file modified" hint on the status bar plus a new refresh key. the underlying problem (old diff on screen, annotations pointing at shifted lines) stays.

3. output contract. revdiff's value is the structured annotation output downstream tools consume. once a session allows edits, those line-indexed annotations become unreliable without reconciliation logic. that's scope creep into exactly what revdiff tries not to do.

difi is a different tool optimized around that edit flow. revdiff deliberately isn't.

I'd rather not add this one. if you have a compelling argument for why revdiff should handle this and how the after-edit state should work (especially around annotations), I'm open to reconsider.

[umputun]

This is not actionable, at least for now. Moving to discussions/ideas.