Do not treat ~nosuchuser as an absolute file name

Derived from Ken Brown’s patch (Bug#36502#97).
* doc/lispref/files.texi (Relative File Names):
* etc/NEWS: Document this.
* src/fileio.c (user_homedir): New function.
(Fexpand_file_name, file_name_absolute_p): Use it.
(search_embedded_absfilename): Simplify via file_name_absolute_p.
* test/src/fileio-tests.el (fileio-tests--no-such-user): New test.

1 files changed, 11 insertions, 0 deletions

diff --git a/test/src/fileio-tests.el b/test/src/fileio-tests.el
index 813ee5f798f..09a5b147e1d 100644
--- a/test/src/fileio-tests.el
+++ b/test/src/fileio-tests.el
@@ -136,3 +136,14 @@ Also check that an encoding error can appear in a symlink."
          (name (expand-file-name "bar")))
     (should (and (file-name-absolute-p name)
                  (not (eq (aref name 0) ?~))))))
+
+(ert-deftest fileio-tests--no-such-user ()
+  "Test file-name-absolute-p on ~nosuchuser."
+  (unless (user-full-name "nosuchuser")
+    (should (not (file-name-absolute-p "~nosuchuser")))
+    (should (not (file-name-absolute-p "~nosuchuser/")))
+    (should (not (file-name-absolute-p "~nosuchuser//")))
+    (should (not (file-name-absolute-p "~nosuchuser/foo")))
+    (should (not (file-name-absolute-p "~nosuchuser/foo/")))
+    (should (not (file-name-absolute-p "~nosuchuser/foo//")))
+    (should (not (file-name-absolute-p "~nosuchuser/foo/bar")))))