Handle project--files-in-directory finding no files better

* lisp/progmodes/project.el (project--find-regexp-in-files):
Signal user-error when passed an empty list of files.

* lisp/progmodes/xref.el (xref-matches-in-files):
Make sure FILES is not empty.

diff --git a/lisp/progmodes/project.el b/lisp/progmodes/project.el
index f46786818586faa5631eb878bd7a33e36c8361f2..1f4cbe96ad8df11e3615e7ce38a88149d64c2106 100644 (file)
--- a/lisp/progmodes/project.el
+++ b/lisp/progmodes/project.el
@@ -480,6 +480,8 @@ pattern to search for."
      nil)))
 
 (defun project--find-regexp-in-files (regexp files)
+  (unless files
+    (user-error "Empty file list"))
   (let ((xrefs (xref-matches-in-files regexp files)))
     (unless xrefs
       (user-error "No matches for: %s" regexp))

diff --git a/lisp/progmodes/xref.el b/lisp/progmodes/xref.el
index 1a34456340508574dcce5c486b55a85bc93884b1..c36a9bd9940bf2e77a745b451317094c8e3c540d 100644 (file)
--- a/lisp/progmodes/xref.el
+++ b/lisp/progmodes/xref.el
@@ -1232,6 +1232,7 @@ IGNORES is a list of glob patterns for files to ignore."
   "Find all matches for REGEXP in FILES.
 Return a list of xref values.
 FILES must be a list of absolute file names."
+  (cl-assert (consp files))
   (pcase-let*
       ((output (get-buffer-create " *project grep output*"))
        (`(,grep-re ,file-group ,line-group . ,_) (car grep-regexp-alist))