fix: handle an invalid GitHub token

src/gimmegit/_cli.py

@@ -459,8 +459,10 @@ def get_default_branch(cloned: git.Repo) -> str:
 
 def get_github_login() -> str:
     api = github.Github(GITHUB_TOKEN)
-    user = api.get_user()
-    return user.login
+    try:
+        return api.get_user().login  # If this raises, it will be 'login' that raises.
+    except github.BadCredentialsException:
+        raise ValueError("GitHub rejected the token. Has the token expired?")
 
 
 def get_github_upstream(owner: str, project: str) -> _remote.Remote | None:
@@ -469,6 +471,8 @@ def get_github_upstream(owner: str, project: str) -> _remote.Remote | None:
     api = github.Github(GITHUB_TOKEN)
     try:
         repo = api.get_repo(f"{owner}/{project}")
+    except github.BadCredentialsException:
+        raise ValueError("GitHub rejected the token. Has the token expired?")
     except github.UnknownObjectException:
         raise ValueError(
             f"Unable to find '{owner}/{project}' on GitHub. Do you have access to the repo?"

tests/functional/helpers_functional.py

@@ -31,6 +31,13 @@ def token_env() -> dict[str, str]:
     return env
 
 
+def bad_token_env() -> dict[str, str]:
+    env = os.environ.copy()
+    env["GIMMEGIT_FORCE_STDOUT"] = "1"
+    env["GIMMEGIT_GITHUB_TOKEN"] = "invalid-token"
+    return env
+
+
 def get_branch(dir: Path) -> str:
     result = subprocess.run(
         ["git", "branch", "--show-current"],

tests/functional/test_token.py

@@ -69,6 +69,60 @@ def test_invalid_repo_token(uv_run, test_dir):
     assert not (test_dir / "invalid").exists()
 
 
+def test_bad_token_no_owner(uv_run, test_dir):
+    command = [
+        *uv_run,
+        "gimmegit",
+        *helpers.no_ssh,
+        "jubilant",
+    ]
+    result = subprocess.run(
+        command,
+        cwd=test_dir,
+        env=helpers.bad_token_env(),
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+    assert result.returncode == 1
+    expected_stdout = """\
+Getting repo details
+"""
+    assert result.stdout == expected_stdout
+    expected_stderr = """\
+Error: GitHub rejected the token. Has the token expired?
+"""
+    assert result.stderr == expected_stderr
+    assert not (test_dir / "jubilant").exists()
+
+
+def test_bad_token_no_upstream_owner(uv_run, test_dir):
+    command = [
+        *uv_run,
+        "gimmegit",
+        *helpers.no_ssh,
+        "dwilding/jubilant",
+    ]
+    result = subprocess.run(
+        command,
+        cwd=test_dir,
+        env=helpers.bad_token_env(),
+        capture_output=True,
+        text=True,
+        check=False,
+    )
+    assert result.returncode == 1
+    expected_stdout = """\
+Getting repo details
+"""
+    assert result.stdout == expected_stdout
+    expected_stderr = """\
+Error: GitHub rejected the token. Has the token expired?
+"""
+    assert result.stderr == expected_stderr
+    assert not (test_dir / "jubilant").exists()
+
+
 @pytest.mark.skipif(helpers.no_token.condition, reason=helpers.no_token.reason)
 def test_u_sets_upstream_owner(uv_run, test_dir):
     command = [