[RFH PATCH] Teach the emacs git mode about core.excludesfile

["Karl Hasselström" <kha@treskal.com>]

If there is a core.excludesfile option specified, let the emacs git
mode take exclude patterns from that file, since that's what the docs
say, and what everyone else is already doing.

Signed-off-by: Karl Hasselström <kha@treskal.com>
---

This is a Request For Help. The patch works, but is clearly the work
of someone who is not very fluent in elisp. Just look at all that
duplicated code I've introduced!

 contrib/emacs/git.el |   19 ++++++++++++++++---
 1 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/contrib/emacs/git.el b/contrib/emacs/git.el
index 53dd703..357e6d2 100644
--- a/contrib/emacs/git.el
+++ b/contrib/emacs/git.el
@@ -589,6 +589,13 @@ Return the list of files that haven't been handled."
           (when node (push (ewoc-data node) unmerged-files))))
       (git-set-files-state unmerged-files 'unmerged))))
 
+(defun git-core-excludesfile ()
+  "The file core.excludesfile, or nil if it isn't specified."
+  (let ((fn (git-config "core.excludesfile")))
+    (if (and fn (file-readable-p fn))
+        fn
+      nil)))
+
 (defun git-update-status-files (files &optional default-state)
   "Update the status of FILES from the index."
   (unless git-status (error "Not in git-status buffer."))
@@ -600,9 +607,15 @@ Return the list of files that haven't been handled."
     (git-run-ls-unmerged status files)
     (when (and (or (not files) remaining-files)
                (file-readable-p ".git/info/exclude"))
-      (setq remaining-files (git-run-ls-files status remaining-files
-                                              'unknown "-o" "--exclude-from=.git/info/exclude"
-                                              (concat "--exclude-per-directory=" git-per-dir-ignore-file))))
+      (let ((ce (git-core-excludesfile)))
+        (if ce
+            (setq remaining-files (git-run-ls-files status remaining-files
+                                                    'unknown "-o" "--exclude-from=.git/info/exclude"
+                                                    (concat "--exclude-per-directory=" git-per-dir-ignore-file)
+                                                    (concat "--exclude-from=" ce)))
+          (setq remaining-files (git-run-ls-files status remaining-files
+                                                  'unknown "-o" "--exclude-from=.git/info/exclude"
+                                                  (concat "--exclude-per-directory=" git-per-dir-ignore-file))))))
     ; mark remaining files with the default state (or remove them if nil)
     (when remaining-files
       (if default-state