* lisp/vc/diff-mode.el: Avoid re-initializing buffer in diff-syntax

(diff--syntax-file-attributes): New var.
(diff-syntax-fontify-hunk): Detect when we're reusing the same buffer as
last time, to avoid re-initializing it.  Skip the
diff-syntax-fontify-revisions hash-table, since buffer-alist plays the
same role.
(diff-syntax-fontify-revisions): Delete var.
1 job for master in 50 minutes and 4 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Test
failed #1317
test-all

00:50:04

 
Name Stage Failure
failed
test-all Test
Makefile:313: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
Makefile:288: recipe for target 'check-expensive' failed
make[1]: *** [check-expensive] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
Makefile:962: recipe for target 'check-expensive' failed
make: *** [check-expensive] Error 2
ERROR: Job failed: exit code 1