master 7fad959: Ensure that byte compilation works for relative files (Bug#45287).

[Philipp Stephani]

branch: master
commit 7fad9591142f9d9d0bfce37dd8c65a847dbe8aa9
Author: Philipp Stephani <phst@google.com>
Commit: Philipp Stephani <phst@google.com>

    Ensure that byte compilation works for relative files (Bug#45287).
    
    * lisp/emacs-lisp/bytecomp.el (byte-compile-file): Don’t fail if
    target filename doesn’t contain a directory name.
    
    * test/lisp/emacs-lisp/bytecomp-tests.el
    (bytecomp-tests--target-file-no-directory): New unit test.
---
 lisp/emacs-lisp/bytecomp.el            |  6 +++++-
 test/lisp/emacs-lisp/bytecomp-tests.el | 15 +++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index e23bb9f..64f2c01 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -1967,7 +1967,11 @@ See also `emacs-lisp-byte-compile-and-load'."
                  ;; We attempt to create a temporary file in the
                  ;; target directory, so the target directory must be
                  ;; writable.
-                 (file-writable-p (file-name-directory target-file)))
+                 (file-writable-p
+                  (file-name-directory
+                   ;; Need to expand in case TARGET-FILE doesn't
+                   ;; include a directory (Bug#45287).
+                   (expand-file-name target-file))))
            ;; We must disable any code conversion here.
            (let* ((coding-system-for-write 'no-conversion)
                   ;; Write to a tempfile so that if another Emacs
diff --git a/test/lisp/emacs-lisp/bytecomp-tests.el 
b/test/lisp/emacs-lisp/bytecomp-tests.el
index c2a3e3b..4a6e28f 100644
--- a/test/lisp/emacs-lisp/bytecomp-tests.el
+++ b/test/lisp/emacs-lisp/bytecomp-tests.el
@@ -1016,6 +1016,21 @@ mountpoint (Bug#44631)."
           (set-file-modes directory #o700)
           (delete-directory directory :recursive))))))
 
+(ert-deftest bytecomp-tests--target-file-no-directory ()
+  "Check that Bug#45287 is fixed."
+  (let ((directory (make-temp-file "bytecomp-tests-" :directory)))
+    (unwind-protect
+        (let* ((default-directory directory)
+               (byte-compile-dest-file-function (lambda (_) "test.elc"))
+               (byte-compile-error-on-warn t))
+          (write-region "" nil "test.el" nil nil nil 'excl)
+          (should (byte-compile-file "test.el"))
+          (should (file-regular-p "test.elc"))
+          (should (cl-plusp (file-attribute-size
+                             (file-attributes "test.elc")))))
+      (with-demoted-errors "Error cleaning up directory: %s"
+        (delete-directory directory :recursive)))))
+
 ;; Local Variables:
 ;; no-byte-compile: t
 ;; End: