bug#53343: 29.0.50; assertion failure in diff--iterate-hunks

[Lars Ingebrigtsen]

Stephen Berman <stephen.berman@gmx.net> writes:

> On the other hand, I get the assertion failure with the above recipe in
> emacs-28 and emacs-27, and it seems unlikely that such a bug in
> diff-mode would have gone unnoticed till now, so maybe the diff is
> malformed.  (Though if so, why does the failure not happen when visiting
> the file containing the diff?)

I tried

(setq debug-on-error t)

put the diff in a file, and got a backtrace when loading it.

Debugger entered--Lisp error: (error "Unknown diff hunk type")
  signal(error ("Unknown diff hunk type"))
  error("Unknown diff hunk type")
  diff-hunk-text("" nil nil)
  diff-syntax-fontify-hunk(506 506 t)
etc

So I've now made that function less assertative, and that fixes this
issue.

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   bloggy blog: http://lars.ingebrigtsen.no