Commit 85fbdf02 authored by Stefan Monnier's avatar Stefan Monnier

diff-font-lock-syntax: clarify distinction between t and hunk-also

* lisp/vc/diff-mode.el (diff-font-lock-syntax): Rework docstring.
(diff-syntax-fontify-hunk): Never use the hunk method when
diff-font-lock-syntax is just t.
parent d96b672f
Pipeline #1230 failed with stage
in 60 minutes
......@@ -116,7 +116,7 @@ You can always manually refine a hunk with `diff-refine-hunk'."
"If non-nil, diff hunk font-lock includes source language syntax highlighting.
This highlighting is the same as added by `font-lock-mode'
when corresponding source files are visited normally.
Syntax highlighting is added over diff own highlighted changes.
Syntax highlighting is added over diff-mode's own highlighted changes.
If t, the default, highlight syntax only in Diff buffers created by Diff
commands that compare files or by VC commands that compare revisions.
......@@ -126,17 +126,17 @@ For diffs against the working-tree version of a file, the highlighting is
based on the current file contents. File-based fontification tries to
infer fontification from the compared files.
If revision-based or file-based method fails, use hunk-based method to get
fontification from hunk alone if the value is `hunk-also'.
If `hunk-only', fontification is based on hunk alone, without full source.
If `hunk-only' fontification is based on hunk alone, without full source.
It tries to highlight hunks without enough context that sometimes might result
in wrong fontification. This is the fastest option, but less reliable."
in wrong fontification. This is the fastest option, but less reliable.
If `hunk-also', use reliable file-based syntax highlighting when available
and hunk-based syntax highlighting otherwise as a fallback."
:version "27.1"
:type '(choice (const :tag "Don't highlight syntax" nil)
(const :tag "Hunk-based also" hunk-also)
(const :tag "Hunk-based only" hunk-only)
(const :tag "Highlight syntax" t)))
(const :tag "Highlight syntax" t)
(const :tag "Allow hunk-based fallback" hunk-also)))
(defvar diff-vc-backend nil
"The VC backend that created the current Diff buffer, if any.")
......@@ -2434,67 +2434,61 @@ When OLD is non-nil, highlight the hunk from the old source."
(string-to-number (match-string 2 line)))
(list (string-to-number line) 1)))) ; One-line diffs
(props
(cond
((and diff-vc-backend (not (eq diff-font-lock-syntax 'hunk-only)))
(let* ((file (diff-find-file-name old t))
(revision (and file (if (not old) (nth 1 diff-vc-revisions)
(or (nth 0 diff-vc-revisions)
(vc-working-revision file))))))
(if file
(if (not revision)
;; Get properties from the current working revision
(when (and (not old) (file-exists-p file)
(file-regular-p file))
(let ((buf (get-file-buffer (expand-file-name file))))
;; Try to reuse an existing buffer
(if buf
(with-current-buffer buf
(diff-syntax-fontify-props nil text line-nb))
;; Get properties from the file
(with-temp-buffer
(insert-file-contents file)
(diff-syntax-fontify-props file text line-nb)))))
;; Get properties from a cached revision
(let* ((buffer-name (format " *diff-syntax:%s.~%s~*"
(expand-file-name file)
revision))
(buffer (gethash buffer-name
diff-syntax-fontify-revisions)))
(unless (and buffer (buffer-live-p buffer))
(let* ((vc-buffer (ignore-errors
(vc-find-revision-no-save
(expand-file-name file) revision
diff-vc-backend
(get-buffer-create buffer-name)))))
(when vc-buffer
(setq buffer vc-buffer)
(puthash buffer-name buffer
diff-syntax-fontify-revisions))))
(when buffer
(with-current-buffer buffer
(diff-syntax-fontify-props file text line-nb)))))
;; If file is unavailable, get properties from the hunk alone
(setq file (car (diff-hunk-file-names old)))
(with-temp-buffer
(insert text)
(diff-syntax-fontify-props file text line-nb t)))))
((and diff-default-directory
(not (eq diff-font-lock-syntax 'hunk-only)))
(let ((file (car (diff-hunk-file-names old))))
(if (and file (file-exists-p file) (file-regular-p file))
;; Try to get full text from the file
(with-temp-buffer
(insert-file-contents file)
(diff-syntax-fontify-props file text line-nb))
;; Otherwise, get properties from the hunk alone
(with-temp-buffer
(insert text)
(diff-syntax-fontify-props file text line-nb t)))))
((memq diff-font-lock-syntax '(hunk-also hunk-only))
(let ((file (car (diff-hunk-file-names old))))
(with-temp-buffer
(insert text)
(diff-syntax-fontify-props file text line-nb t)))))))
(or
(when (and diff-vc-backend
(not (eq diff-font-lock-syntax 'hunk-only)))
(let* ((file (diff-find-file-name old t))
(revision (and file (if (not old) (nth 1 diff-vc-revisions)
(or (nth 0 diff-vc-revisions)
(vc-working-revision file))))))
(when file
(if (not revision)
;; Get properties from the current working revision
(when (and (not old) (file-exists-p file)
(file-regular-p file))
(let ((buf (get-file-buffer (expand-file-name file))))
;; Try to reuse an existing buffer
(if buf
(with-current-buffer buf
(diff-syntax-fontify-props nil text line-nb))
;; Get properties from the file
(with-temp-buffer
(insert-file-contents file)
(diff-syntax-fontify-props file text line-nb)))))
;; Get properties from a cached revision
(let* ((buffer-name (format " *diff-syntax:%s.~%s~*"
(expand-file-name file)
revision))
(buffer (gethash buffer-name
diff-syntax-fontify-revisions)))
(unless (and buffer (buffer-live-p buffer))
(let* ((vc-buffer (ignore-errors
(vc-find-revision-no-save
(expand-file-name file) revision
diff-vc-backend
(get-buffer-create buffer-name)))))
(when vc-buffer
(setq buffer vc-buffer)
(puthash buffer-name buffer
diff-syntax-fontify-revisions))))
(when buffer
(with-current-buffer buffer
(diff-syntax-fontify-props file text line-nb))))))))
(let ((file (car (diff-hunk-file-names old))))
(cond
((and file diff-default-directory
(not (eq diff-font-lock-syntax 'hunk-only))
(not diff-vc-backend)
(file-readable-p file) (file-regular-p file))
;; Try to get full text from the file.
(with-temp-buffer
(insert-file-contents file)
(diff-syntax-fontify-props file text line-nb)))
;; Otherwise, get properties from the hunk alone
((memq diff-font-lock-syntax '(hunk-also hunk-only))
(with-temp-buffer
(insert text)
(diff-syntax-fontify-props file text line-nb t))))))))
;; Put properties over the hunk text
(goto-char beg)
......
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