bug#17467: 24.3; locate-library returning spurious path

[Alex Kosorukoff]

I like the idea of optimizing out the second string-match, though that variant matched tramp.el.old which is not a valid library name. Here is a modifed version using the same idea except it skips files like tramp.el.old.

# Bazaar merge directive format 2 (Bazaar 0.90)

# revision_id: alex@3form.com-20140512042218-zjdg3v68bbja2rj2

# target_branch: :parent

# testament_sha1: 330ab5b4527e49ea46d8d16a6d47e5822247ce77

# timestamp: 2014-05-11 21:23:50 -0700

# base_revision_id: monnier@iro.umontreal.ca-20140511034953-\

#   1mzcrftziwhrw9hl

# 

# Begin patch

=== modified file 'lisp/subr.el'

--- lisp/subr.el        2014-04-09 01:48:07 +0000

+++ lisp/subr.el        2014-05-12 04:22:18 +0000

@@ -1857,10 +1857,14 @@

                                        load-path (get-load-suffixes)))

                     nil nil

                     t))

-  (let ((file (locate-file library

-                          (or path load-path)

-                          (append (unless nosuffix (get-load-suffixes))

-                                  load-file-rep-suffixes))))

+  (let ((file

+         (locate-file

+          library

+          (or path load-path)

+          (unless nosuffix

+            (if (string-match "\\.elc?\\(\\.gz\\)?\\'" library)

+                (if (= 2 (length (match-data))) load-file-rep-suffixes)

+              (get-load-suffixes))))))

     (if interactive-call

        (if file

            (message "Library is file %s" (abbreviate-file-name file))

# Begin bundle

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On Sun, May 11, 2014 at 7:18 PM, Stefan Monnier <monnier@iro.umontreal.ca> wrote:

> I think these file names are more appropriate for data files, not
> executable ones.  It is undesirable that a name "tramp.gz" will shadow a
> valid library file "tramp.elc" that won't be found as a result.

I think I'm beginning to see what you mean.  So far we have simply
considered "if it hurts, don't do it".  And it worked well enough.

> When you say those names aren't spurious, do you have a particular
> example of an emacs elisp library in mind which file name ends with
> a suffix other than .el .elc .el.gz .elc.gz?

There are a few (~/.emacs being the most obvious), but admittedly,
I think they all share the property of not being searched for in
load-path.  So we could probably strengthen the search along the lines
you suggest without (hopefully) breaking existing code with a hack along
the lines of the one below.


        Stefan


=== modified file 'lisp/subr.el'
--- lisp/subr.el        2014-04-15 17:03:15 +0000
+++ lisp/subr.el        2014-05-12 02:15:04 +0000
@@ -1878,10 +1878,15 @@

                                        load-path (get-load-suffixes)))
                     nil nil
                     t))
-  (let ((file (locate-file library
-                          (or path load-path)
-                          (append (unless nosuffix (get-load-suffixes))
-                                  load-file-rep-suffixes))))

+  (let* ((suffixes
+          (nconc (unless nosuffix (get-load-suffixes))
+                 (when (or (file-name-absolute-p library)
+                           ;; (load "foo.el") should find /bar/foo.el.gz,
+                           ;; but (load "foo") should not find /bar/foo.gz.
+                           (string-match "\\.el\\(\\.[[:alnum:]]+\\)?"
+                                         library))
+                   load-file-rep-suffixes)))
+         (file (locate-file library (or path load-path) suffixes)))

     (if interactive-call
        (if file
            (message "Library is file %s" (abbreviate-file-name file))