Add option 'ffap-prefer-remote-file' (bug#78925)

This option only affects absolute filenames that are found by
ffap-file-at-point in buffers with remote default directory.

The handling of relative filenames in above buffers remains
unchanged: ffap-file-at-point returns the relative filename,
which can be converted to a remote absolute filename by
subsequent callers (e.g. ffap) using expand-file-name.

* lisp/ffap.el (ffap-prefer-remote-file): New user option.
(ffap-file-exists-string): Add an optional argument to allow the
check of existence of absolute filename on the remote host.
(ffap-file-at-point): Always find remote files in remote context
if the new option is non-nil.
* test/lisp/ffap-tests.el (ffap-test-remote): Add a test.
* etc/NEWS: Announce the change.

1 files changed, 22 insertions, 0 deletions

diff --git a/test/lisp/ffap-tests.el b/test/lisp/ffap-tests.el
index ea5e745bfaf..2bf5d8c79cd 100644
--- a/test/lisp/ffap-tests.el
+++ b/test/lisp/ffap-tests.el
@@ -25,6 +25,7 @@
 
 (require 'cl-lib)
 (require 'ert)
+(require 'tramp)
 (require 'ert-x)
 (require 'ffap)
 
@@ -289,6 +290,27 @@ End of search list.
     (should (member (expand-file-name "/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/15.0.0/include")
                     (ffap--c-path)))))
 
+(ert-deftest ffap-test-remote ()
+  (skip-unless
+   (ignore-errors
+     (and
+      (file-remote-p ert-remote-temporary-file-directory)
+      (file-directory-p ert-remote-temporary-file-directory)
+      (file-writable-p ert-remote-temporary-file-directory))))
+  (let* ((ffap-prefer-remote-file t)
+         (default-directory
+          (expand-file-name ert-remote-temporary-file-directory))
+         (test-file (expand-file-name "ffap-test" default-directory)))
+    (with-temp-buffer
+      (ignore-errors (make-empty-file test-file))
+      (insert (file-local-name test-file))
+      (should (equal (ffap-file-at-point) test-file))
+      (erase-buffer)
+      (insert (concat "/usr/bin:" (file-local-name test-file)))
+      (should (equal (ffap-file-at-point) test-file))
+      (delete-file test-file)
+      (should (equal (ffap-file-at-point) default-directory)))))
+
 (provide 'ffap-tests)
 
 ;;; ffap-tests.el ends here