Add fail-safe for extracting header

Some patches don't have the 'in-reply-to' header.

* git-email.el (git-email--extract-header): If the header is not found,
return an empty string.

1 files changed, 5 insertions, 2 deletions

diff --git a/git-email.el b/git-email.el
index a66fd16..40588e5 100644
--- a/git-email.el
+++ b/git-email.el
@@ -50,12 +50,15 @@
   :type 'symbol)
 
 (defun git-email--extract-header (header patch-file)
-  "Extract HEADER from PATCH-FILE."
+  "Extract HEADER from PATCH-FILE.
+If the header is not found, return an empty string."
   (with-temp-buffer
     (insert-file-contents patch-file)
     (goto-char (point-min))
     (buffer-substring-no-properties
-     (re-search-forward (format " *%s: +" header))
+     (if (re-search-forward (format " *%s: +" header) nil t)
+	 (point)
+       (point-at-eol))
      (point-at-eol))))
 
 (defun git-email--extract-diff (patch-file)