Merge branch 'master' into scratch/font_lock_large_filesscratch/font_lock_large_files

1 files changed, 25 insertions, 10 deletions

diff --git a/lisp/emacs-lisp/loaddefs-gen.el b/lisp/emacs-lisp/loaddefs-gen.el
index 3b329357ad9..31e1514193f 100644
--- a/lisp/emacs-lisp/loaddefs-gen.el
+++ b/lisp/emacs-lisp/loaddefs-gen.el
@@ -519,15 +519,21 @@ binds `generated-autoload-file' as a file-local variable, write
 its autoloads into the specified file instead.
 
 The function does NOT recursively descend into subdirectories of the
-directory or directories specified.
+directory or directories specified by DIRS.
 
-If EXTRA-DATA, include this string at the start of the generated
-file.  This will also force generation of OUTPUT-FILE even if
-there are no autoloads to put into the file.
+Optional argument EXCLUDED-FILES, if non-nil, should be a list of
+files, such as preloaded files, whose autoloads should not be written
+to OUTPUT-FILE.
 
-If INCLUDE-PACKAGE-VERSION, include package version data.
+If EXTRA-DATA is non-nil, it should be a string; include that string
+at the beginning of the generated file.  This will also force the
+generation of OUTPUT-FILE even if there are no autoloads to put into
+that file.
 
-If GENERATE-FULL, don't update, but regenerate all the loaddefs files."
+If INCLUDE-PACKAGE-VERSION is non-nil, include package version data.
+
+If GENERATE-FULL is non-nil, regenerate all the loaddefs files anew,
+instead of just updating them with the new/changed autoloads."
   (let* ((files-re (let ((tmp nil))
 		     (dolist (suf (get-load-suffixes))
                        ;; We don't use module-file-suffix below because
@@ -545,6 +551,11 @@ If GENERATE-FULL, don't update, but regenerate all the loaddefs files."
          (updating (and (file-exists-p output-file) (not generate-full)))
          (defs nil))
 
+    ;; Allow the excluded files to be relative.
+    (setq excluded-files
+          (mapcar (lambda (file) (expand-file-name file dir))
+                  excluded-files))
+
     ;; Collect all the autoload data.
     (let ((progress (make-progress-reporter
                      (byte-compile-info
@@ -583,7 +594,8 @@ If GENERATE-FULL, don't update, but regenerate all the loaddefs files."
       ;; We have some data, so generate the loaddef files.  First
       ;; group per output file.
       (dolist (fdefs (seq-group-by #'car defs))
-        (let ((loaddefs-file (car fdefs)))
+        (let ((loaddefs-file (car fdefs))
+              hash)
           (with-temp-buffer
             (if (and updating (file-exists-p loaddefs-file))
                 (insert-file-contents loaddefs-file)
@@ -593,6 +605,7 @@ If GENERATE-FULL, don't update, but regenerate all the loaddefs files."
               (when extra-data
                 (insert extra-data)
                 (ensure-empty-lines 1)))
+            (setq hash (buffer-hash))
             ;; Then group by source file (and sort alphabetically).
             (dolist (section (sort (seq-group-by #'cadr (cdr fdefs))
                                    (lambda (e1 e2)
@@ -629,9 +642,11 @@ If GENERATE-FULL, don't update, but regenerate all the loaddefs files."
                     (loaddefs-generate--print-form def))
                   (unless (bolp)
                     (insert "\n")))))
-            (write-region (point-min) (point-max) loaddefs-file nil 'silent)
-            (byte-compile-info (file-relative-name loaddefs-file lisp-directory)
-                               t "GEN")))))))
+            ;; Only write the file if we actually made a change.
+            (unless (equal (buffer-hash) hash)
+              (write-region (point-min) (point-max) loaddefs-file nil 'silent)
+              (byte-compile-info
+               (file-relative-name loaddefs-file lisp-directory) t "GEN"))))))))
 
 (defun loaddefs-generate--print-form (def)
   "Print DEF in a format that makes sense for version control."