contrib/hg-test-mode.el

changelog: optionally store added and removed files in changeset extras

As mentioned in an earlier patch, copies._chain() is used a lot in the
changeset-centric version of pathcopies(). It is expensive because it
needs to look at the manifest in order to filter out copies whose
target file has since been removed. I want to store the sets of added
and removed files in the changeset in order to speed that up. This
patch does the writing part of that. It could easily be a separate
config, but it's currently tied to experimental.copies.write-to since
that's the only real use case (it will also make the {file_*} template
keywords faster, but I doubt that anyone cares enough about those to
write extra metadata for them).

The new information is stored in the changeset extras. Since they're
always subsets of the changeset's "files" list, they're stored as
indexes into that list. I've stored the indexes as stringified ints
separated by NUL bytes. The size of 00changelog.d for the hg repo
increased in size by 0.28% percent (compared to the size with only
copy information in the changesets, which in turn is 0.17% larger than
without copy information). We could store only the delta between the
indexes and we could store them in binary, but the chosen format is
more readable.

We could also have implemented this as a cache outside the
changelog. One advantage of doing it that way is that we would get the
speedups from the {file_*} template keywords also on old
repos. Another advantage is that it we can rewrite the cache if we
find a bug in how we calculate the set of files. A disadvantage is
that it would be more complex. Another is that it would surely use
more space. We already write the copy information to the changeset
extras, so it seems like a small step to also write these file sets.

Differential Revision: https://phab.mercurial-scm.org/D6416

;; 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))

(with-eval-after-load "compile"
  ;; Link to Python sources in tracebacks in .t failures.
  (add-to-list 'compilation-error-regexp-alist-alist
               '(hg-test-output-python-tb
                 "^\\+ +File ['\"]\\([^'\"]+\\)['\"], line \\([0-9]+\\)," 1 2))
  (add-to-list 'compilation-error-regexp-alist 'hg-test-output-python-tb)
  ;; Link to source files in test-check-code.t violations.
  (add-to-list 'compilation-error-regexp-alist-alist
               '(hg-test-check-code-output
                 "\\+  \\([^:\n]+\\):\\([0-9]+\\):$" 1 2))
  (add-to-list 'compilation-error-regexp-alist 'hg-test-check-code-output))

(defun hg-test-mode--test-one-error-line-regexp (test)
  (erase-buffer)
  (setq compilation-locs (make-hash-table))
  (insert (car test))
  (compilation-parse-errors (point-min) (point-max))
  (let ((msg (get-text-property 1 'compilation-message)))
    (should msg)
    (let ((loc (compilation--message->loc msg))
          (line (nth 1 test))
          (file (nth 2 test)))
      (should (equal (compilation--loc->line loc) line))
      (should (equal (caar (compilation--loc->file-struct loc)) file)))
      msg))

(require 'ert)
(ert-deftest hg-test-mode--compilation-mode-support ()
  "Test hg-specific compilation-mode regular expressions"
  (require 'compile)
  (with-temp-buffer
    (font-lock-mode -1)
    (mapc 'hg-test-mode--test-one-error-line-regexp
          '(
            ("+  contrib/debugshell.py:37:" 37 "contrib/debugshell.py")
            ("+    File \"/tmp/hg/mercurial/commands.py\", line 3115, in help_"
             3115 "/tmp/hg/mercurial/commands.py")
            ("+    File \"mercurial/dispatch.py\", line 225, in dispatch"
             225 "mercurial/dispatch.py")))))


(provide 'hg-test-mode)