fix: empty gitstatus on paths without repo (#4907)

* fix: empty gitstatus on paths without repo

fixes #4900

* docs: add news item

* fix: failing test because of cache in git-dir per cwd

news/fix-empty-gitstatus.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* ``gitstatus`` Prompt-field would be empty on paths without git setup.
+
+**Security:**
+
+* <news item>

tests/prompt/test_gitstatus.py

@@ -1,3 +1,5 @@
+import os
+
 import pytest
 
 from xonsh.prompt import gitstatus
@@ -14,6 +16,7 @@ def prompts(xession):
     fields = xession.env["PROMPT_FIELDS"]
     yield fields
     fields.clear()
+    fields.reset()
 
 
 @pytest.fixture
@@ -71,3 +74,24 @@ def test_gitstatus_clean(prompts, fake_proc):
     assert format(prompts.pick("gitstatus")) == exp
     assert _format_value(prompts.pick("gitstatus"), None, None) == exp
     assert _format_value(prompts.pick("gitstatus"), "{}", None) == exp
+
+
+def test_no_git(prompts, fake_process, tmp_path):
+    os.chdir(tmp_path)
+    err = b"fatal: not a git repository (or any of the parent directories): .git"
+    for cmd in (
+        "git status --porcelain --branch",
+        "git rev-parse --git-dir",
+        "git diff --numstat",
+    ):
+        fake_process.register_subprocess(
+            command=cmd,
+            stderr=err,
+            returncode=128,
+        )
+
+    exp = ""
+    assert prompts.pick_val("gitstatus.repo_path") == ""
+    assert format(prompts.pick("gitstatus")) == exp
+    assert _format_value(prompts.pick("gitstatus"), None, None) == exp
+    assert _format_value(prompts.pick("gitstatus"), "{}", None) == exp

xonsh/prompt/gitstatus.py

@@ -319,5 +319,11 @@ class GitStatus(MultiPromptField):
                 continue
             yield frag
 
+    def _collect(self, ctx):
+        if not ctx.pick_val(repo_path):
+            # no need to display any other fragments
+            return
+        yield from super()._collect(ctx)
+
 
 gitstatus = GitStatus()