Fix globbing when there is a single match

See https://github.com/anishathalye/dotbot/issues/282 and
https://github.com/anishathalye/dotbot/issues/315.

This patch simplifies the implementation, removing special-case handling
for the cases of zero matches and one match. Instead, any situation
where `glob: true` is specified and the path contains a glob character
(any of "?", "*", or "[") is treated as a glob case. The reason we check
both `use_glob` and `_has_glob_chars()` is to more gracefully handle the
case where the user has enabled globs by default, but most links do not
contain glob characters and should not be treated as globs.

dotbot/plugins/link.py

@@ -59,32 +59,8 @@ class Link(Plugin):
                 self._log.lowinfo("Skipping %s" % destination)
                 continue
             path = os.path.normpath(os.path.expandvars(os.path.expanduser(path)))
-            if use_glob:
+            if use_glob and self._has_glob_chars(path):
                 glob_results = self._create_glob_results(path, exclude_paths)
-                if len(glob_results) == 0:
-                    self._log.lowinfo("Globbing couldn't find anything matching " + str(path))
-                    continue
-                if len(glob_results) == 1 and destination[-1] == "/":
-                    self._log.error("Ambiguous action requested.")
-                    self._log.error(
-                        "No wildcard in glob, directory use undefined: "
-                        + destination
-                        + " -> "
-                        + str(glob_results)
-                    )
-                    self._log.warning("Did you want to link the directory or into it?")
-                    success = False
-                    continue
-                elif len(glob_results) == 1 and destination[-1] != "/":
-                    # perform a normal link operation
-                    if create:
-                        success &= self._create(destination)
-                    if force or relink:
-                        success &= self._delete(path, destination, relative, canonical_path, force)
-                    success &= self._link(
-                        path, destination, relative, canonical_path, ignore_missing
-                    )
-                else:
                 self._log.lowinfo("Globs from '" + path + "': " + str(glob_results))
                 for glob_full_item in glob_results:
                     # Find common dirname between pattern and the item:
@@ -154,6 +130,9 @@ class Link(Plugin):
         else:
             return source
 
+    def _has_glob_chars(self, path):
+        return any(i in path for i in "?*[")
+
     def _glob(self, path):
         """
         Wrap `glob.glob` in a python agnostic way, catching errors in usage.

tests/test_link.py

@@ -270,7 +270,7 @@ def test_link_glob_4(home, dotfiles, run_dotbot):
 
 
 @pytest.mark.parametrize("path", ("foo", "foo/"))
-def test_link_glob_ambiguous_failure(path, home, dotfiles, run_dotbot):
+def test_link_glob_ignore_no_glob_chars(path, home, dotfiles, run_dotbot):
     """Verify ambiguous link globbing fails."""
 
     dotfiles.makedirs("foo")
@@ -286,28 +286,8 @@ def test_link_glob_ambiguous_failure(path, home, dotfiles, run_dotbot):
             }
         ]
     )
-    with pytest.raises(SystemExit):
-        run_dotbot()
-    assert not os.path.exists(os.path.join(home, "foo"))
-
-
-def test_link_glob_ambiguous_success(home, dotfiles, run_dotbot):
-    """Verify the case where ambiguous link globbing succeeds."""
-
-    dotfiles.makedirs("foo")
-    dotfiles.write_config(
-        [
-            {
-                "link": {
-                    "~/foo": {
-                        "path": "foo",
-                        "glob": True,
-                    }
-                }
-            }
-        ]
-    )
     run_dotbot()
+    assert os.path.islink(os.path.join(home, "foo"))
     assert os.path.exists(os.path.join(home, "foo"))
 
 
@@ -600,6 +580,26 @@ def test_link_glob_no_match(home, dotfiles, run_dotbot):
     run_dotbot()
 
 
+def test_link_glob_single_match(home, dotfiles, run_dotbot):
+    """Verify linking works even when glob matches exactly one file."""
+    # regression test for https://github.com/anishathalye/dotbot/issues/282
+
+    dotfiles.write("foo/a", "apple")
+    dotfiles.write_config(
+        [
+            {"defaults": {"link": {"glob": True, "create": True}}},
+            {"link": {"~/.config/foo": "foo/*"}},
+        ]
+    )
+    run_dotbot()
+
+    assert not os.path.islink(os.path.join(home, ".config"))
+    assert not os.path.islink(os.path.join(home, ".config", "foo"))
+    assert os.path.islink(os.path.join(home, ".config", "foo", "a"))
+    with open(os.path.join(home, ".config", "foo", "a")) as file:
+        assert file.read() == "apple"
+
+
 @pytest.mark.skipif(
     "sys.platform[:5] == 'win32'",
     reason="These if commands won't run on Windows",