fix(utils/url): handle Windows relative path backslash when caching file

Fix #61040.

Jinja imports with relative paths was introduced in #47490.

Unfortunately, relative imports have never been working on Windows.
That's due to backslashes being unhandled by the `cache_file` function:

* https://github.com/saltstack/salt/blob/7275ecf073197faed26f3a571c25fcd59bfbfd60/salt/utils/jinja.py#L114

Instead of getting:

* `salt://packages/map.jinja`

We're ending up with:

* `salt://packages\map.jinja`

Thus, the file isn't cached from the master.

There's actually a `FIXME` note about it:

* https://github.com/saltstack/salt/blob/7275ecf073197faed26f3a571c25fcd59bfbfd60/salt/utils/jinja.py#L136

And the replacement is actually done for setting `tpldir`:

* https://github.com/saltstack/salt/blob/7275ecf073197faed26f3a571c25fcd59bfbfd60/salt/utils/jinja.py#L165

This commit ensures the replacement is also done when caching files.

changelog/61829.fixed

@@ -0,0 +1 @@
+Ensure that `salt://` URIs never contain backslashes, converting them to forward slashes instead.  A specific situation to handle is caching files on Windows minions, where Jinja relative imports introduce a backslash into the path.

salt/utils/url.py

@@ -41,6 +41,7 @@ def create(path, saltenv=None):
     """
     join `path` and `saltenv` into a 'salt://' URL.
     """
+    path = path.replace("\\", "/")
     if salt.utils.platform.is_windows():
         path = salt.utils.path.sanitize_win_path(path)
     path = salt.utils.data.decode(path)

tests/pytests/unit/utils/jinja/test_salt_cache_loader.py

@@ -176,8 +176,8 @@ def test_relative_import(
     result = tmpl.render()
     assert result == "Hey world !a b !"
     assert len(fc.requests) == 3
-    assert fc.requests[0]["path"] == os.path.join("salt://relative", "rhello")
-    assert fc.requests[1]["path"] == os.path.join("salt://relative", "rmacro")
+    assert fc.requests[0]["path"] == "salt://relative/rhello"
+    assert fc.requests[1]["path"] == "salt://relative/rmacro"
     assert fc.requests[2]["path"] == "salt://macro"
     # This must fail when rendered: attempts to import from outside file root
     template = jinja.get_template("relative/rescape")

tests/unit/utils/test_url.py

@@ -68,6 +68,32 @@ def test_create_url_saltenv(self):
 
         self.assertEqual(salt.utils.url.create(path, saltenv), url)
 
+    def test_create_url_with_backslash_in_path(self):
+        """
+        Test creating a 'salt://' URL
+        """
+        src_path = r"? interesting\&path.filetype"
+        tgt_path = "? interesting/&path.filetype"
+        url = "salt://" + tgt_path
+        if salt.utils.platform.is_windows():
+            url = "salt://_ interesting/&path.filetype"
+
+        self.assertEqual(salt.utils.url.create(src_path), url)
+
+    def test_create_url_saltenv_with_backslash_in_path(self):
+        """
+        Test creating a 'salt://' URL with a saltenv
+        """
+        saltenv = "raumklang"
+        src_path = r"? interesting\&path.filetype"
+        tgt_path = "? interesting/&path.filetype"
+        if salt.utils.platform.is_windows():
+            tgt_path = "_ interesting/&path.filetype"
+
+        url = "salt://" + tgt_path + "?saltenv=" + saltenv
+
+        self.assertEqual(salt.utils.url.create(src_path, saltenv), url)
+
     # is_escaped tests
 
     def test_is_escaped_windows(self):