contrib/hg-test-mode.el

convert: don't drop commits that are empty in the source when using --filemap

I ran into this when using `hg lfconvert --to-normal` (which uses the filemap
class internally), and saw that commits with nothing but a branch change were
dropped.  We could put in an option that only lfconvert uses internally.  But
silently dropping anything other than a commit where all changes were excluded
seems unintended.  For example, there's a message in mercurial_sink.putcommit()
if it drops an empty commit.  (And the reason that isn't kicking in here is
because lfconvert isn't passing --filemap, so the self.filemapmode conditional
there is always False.)

The naive change of `return not files` broke test-convert-filemap.t, so this is
a little more elaborate than needed for converting from largefiles.

;; hg-test-mode.el - Major mode for editing Mercurial tests
;;
;; Copyright 2014 Matt Mackall <[e-mail]>
;; "I have no idea what I'm doing"
;;
;; This software may be used and distributed according to the terms of the
;; GNU General Public License version 2 or any later version.
;;
;; To enable, add something like the following to your .emacs:
;;
;; (if (file-exists-p "~/hg/contrib/hg-test-mode.el")
;;    (load "~/hg/contrib/hg-test-mode.el"))

(defvar hg-test-mode-hook nil)

(defvar hg-test-mode-map
  (let ((map (make-keymap)))
    (define-key map "\C-j" 'newline-and-indent)
    map)
  "Keymap for hg test major mode")

(add-to-list 'auto-mode-alist '("\\.t\\'" . hg-test-mode))

(defconst hg-test-font-lock-keywords-1
  (list
   '("^  \\(\\$\\|>>>\\) " 1 font-lock-builtin-face)
   '("^  \\(>\\|\\.\\.\\.\\) " 1 font-lock-constant-face)
   '("^  \\([[][0-9]+[]]\\)$" 1 font-lock-warning-face)
   '("^  \\(.*?\\)\\(\\( [(][-a-z]+[)]\\)*\\)$" 1 font-lock-string-face)
   '("\\$?\\(HG\\|TEST\\)\\w+=?" . font-lock-variable-name-face)
   '("^  \\(.*?\\)\\(\\( [(][-a-z]+[)]\\)+\\)$" 2 font-lock-type-face)
   '("^#.*" . font-lock-preprocessor-face)
   '("^\\([^ ].*\\)$" 1 font-lock-comment-face)
   )
  "Minimal highlighting expressions for hg-test mode")

(defvar hg-test-font-lock-keywords hg-test-font-lock-keywords-1
  "Default highlighting expressions for hg-test mode")

(defvar hg-test-mode-syntax-table
  (let ((st (make-syntax-table)))
    (modify-syntax-entry ?\" "w" st) ;; disable standard quoting
    st)
"Syntax table for hg-test mode")

(defun hg-test-mode ()
  (interactive)
  (kill-all-local-variables)
  (use-local-map hg-test-mode-map)
  (set-syntax-table hg-test-mode-syntax-table)
  (set (make-local-variable 'font-lock-defaults) '(hg-test-font-lock-keywords))
  (setq major-mode 'hg-test-mode)
  (setq mode-name "hg-test")
  (run-hooks 'hg-test-mode-hook))

(provide 'hg-test-mode)