fix 1180 provide dummy scmversion for dump

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+
+## v9.0.1
+
+### Fixed
+
+- fix #1180: ensure version dumping works when no scm_version is given (problems in downstreams)
+
+
 ## v9.0.0
 
 ### Breaking

src/setuptools_scm/_integration/dump_version.py

@@ -95,19 +95,34 @@ def _validate_template(target: Path, template: str | None) -> str:
         return template
 
 
+class DummyScmVersion:
+    @property
+    def short_node(self) -> str | None:
+        return None
+
+
 def write_version_to_path(
-    target: Path, template: str | None, version: str, scm_version: ScmVersion | None
+    target: Path,
+    template: str | None,
+    version: str,
+    scm_version: ScmVersion | None = None,
 ) -> None:
     final_template = _validate_template(target, template)
     log.debug("dump %s into %s", version, target)
     version_tuple = _version_as_tuple(version)
-    if scm_version is not None:
-        content = final_template.format(
-            version=version,
-            version_tuple=version_tuple,
-            scm_version=scm_version,
+    if scm_version is None:
+        warnings.warn(
+            "write_version_to_path called without scm_version parameter. "
+            "This will be required in a future version. "
+            "Pass scm_version=None explicitly to suppress this warning.",
+            DeprecationWarning,
+            stacklevel=2,
         )
-    else:
-        content = final_template.format(version=version, version_tuple=version_tuple)
+
+    content = final_template.format(
+        version=version,
+        version_tuple=version_tuple,
+        scm_version=scm_version or DummyScmVersion(),
+    )
 
     target.write_text(content, encoding="utf-8")

testing/test_functions.py

@@ -293,3 +293,61 @@ def test_has_command_logs_stderr(caplog: pytest.LogCaptureFixture) -> None:
 def test_tag_to_version(tag: str, expected_version: str) -> None:
     version = str(tag_to_version(tag, c))
     assert version == expected_version
+
+
+def test_write_version_to_path_deprecation_warning_none(tmp_path: Path) -> None:
+    """Test that write_version_to_path warns when scm_version=None is passed."""
+    from setuptools_scm._integration.dump_version import write_version_to_path
+
+    target_file = tmp_path / "version.py"
+
+    # This should raise a deprecation warning when scm_version=None is explicitly passed
+    with pytest.warns(
+        DeprecationWarning, match="write_version_to_path called without scm_version"
+    ):
+        write_version_to_path(
+            target=target_file,
+            template=None,  # Use default template
+            version="1.2.3",
+            scm_version=None,  # Explicitly passing None should warn
+        )
+
+    # Verify the file was created and contains the expected content
+    assert target_file.exists()
+    content = target_file.read_text(encoding="utf-8")
+
+    # Check that the version is correctly formatted
+    assert "__version__ = version = '1.2.3'" in content
+    assert "__version_tuple__ = version_tuple = (1, 2, 3)" in content
+
+    # Check that commit_id is set to None when scm_version is None
+    assert "__commit_id__ = commit_id = None" in content
+
+
+def test_write_version_to_path_deprecation_warning_missing(tmp_path: Path) -> None:
+    """Test that write_version_to_path warns when scm_version parameter is not provided."""
+    from setuptools_scm._integration.dump_version import write_version_to_path
+
+    target_file = tmp_path / "version.py"
+
+    # This should raise a deprecation warning when scm_version is not provided
+    with pytest.warns(
+        DeprecationWarning, match="write_version_to_path called without scm_version"
+    ):
+        write_version_to_path(
+            target=target_file,
+            template=None,  # Use default template
+            version="1.2.3",
+            # scm_version not provided - should warn
+        )
+
+    # Verify the file was created and contains the expected content
+    assert target_file.exists()
+    content = target_file.read_text(encoding="utf-8")
+
+    # Check that the version is correctly formatted
+    assert "__version__ = version = '1.2.3'" in content
+    assert "__version_tuple__ = version_tuple = (1, 2, 3)" in content
+
+    # Check that commit_id is set to None when scm_version is None
+    assert "__commit_id__ = commit_id = None" in content