(gud-common-init): If file arg has no directory,

let the debugger search PATH, and don't set default-directory.

diff --git a/lisp/gud.el b/lisp/gud.el
index 75e8982..34e740b 100644 (file)
--- a/lisp/gud.el
+++ b/lisp/gud.el
@@ -983,12 +983,29 @@ comint mode, which see."
                      (while (and w (= ?- (aref (car w) 0)))
                        (setq w (cdr w)))
                      (car w)))
+        (file-subst
+         (and file-word (substitute-in-file-name file-word)))
         (args (delq file-word (cdr words)))
+        ;; If a directory was specified, expand the file name.
+        ;; Otherwise, don't expand it, so GDB can use the PATH.
+        ;; A file name without directory is literally valid
+        ;; only if the file exists in ., and in that case,
+        ;; omitting the expansion here has no visible effect.
         (file (and file-word
-                   (expand-file-name (substitute-in-file-name file-word))))
+                   (if (file-name-directory file-subst)
+                       (expand-file-name file-subst)
+                     file-subst)))
         (filepart (and file-word (file-name-nondirectory file))))
     (switch-to-buffer (concat "*gud-" filepart "*"))
-    (and file-word (setq default-directory (file-name-directory file)))
+    ;; Set default-directory to the file's directory.
+    (and file-word
+        ;; Don't set default-directory if no directory was specified.
+        ;; In that case, either the file is found in the current directory,
+        ;; in which case this setq is a no-op,
+        ;; or it is found by searching PATH,
+        ;; in which case we don't know what directory it was found in.
+        (file-name-directory file)
+        (setq default-directory (file-name-directory file)))
     (or (bolp) (newline))
     (insert "Current directory is " default-directory "\n")
     (apply 'make-comint (concat "gud-" filepart) program nil