fix(flit): don't emit null values when importing a flit project

news/3832.bugfix.md

@@ -0,0 +1 @@
+Do not write null values into the generated `pyproject.toml` when importing a flit project that omits `author-email`/`maintainer-email` or sets only one of `include` and `exclude` in `[tool.flit.sdist]`.

src/pdm/formats/flit.py

@@ -35,9 +35,11 @@ def check_fingerprint(project: Project | None, filename: PathLike) -> bool:
 
 
 def _get_author(metadata: dict[str, Any], type_: str = "author") -> list[str]:
-    name = metadata.pop(type_)
+    author = {"name": metadata.pop(type_)}
     email = metadata.pop(f"{type_}-email", None)
-    return cast(list[str], array_of_inline_tables([{"name": name, "email": email}]))
+    if email is not None:
+        author["email"] = email
+    return cast(list[str], array_of_inline_tables([author]))
 
 
 def get_docstring_and_version_via_ast(
@@ -137,9 +139,11 @@ def entry_points(self, value: dict[str, dict[str, str]]) -> dict[str, dict[str,
 
     @convert_from("sdist")
     def includes(self, value: dict[str, list[str]]) -> None:
-        self.settings.setdefault("build", {}).update(
-            {"excludes": value.get("exclude"), "includes": value.get("include")}
-        )
+        build = self.settings.setdefault("build", {})
+        if "exclude" in value:
+            build["excludes"] = value["exclude"]
+        if "include" in value:
+            build["includes"] = value["include"]
         raise Unset()
 
 

tests/test_formats.py

@@ -215,6 +215,38 @@ def test_convert_flit(project):
     assert build["excludes"] == ["doc/*.html"]
 
 
+def test_convert_flit_author_and_maintainer_without_email(project, tmp_path):
+    pyproject_file = tmp_path / "pyproject.toml"
+    pyproject_file.write_text(
+        '[tool.flit.metadata]\nmodule = "flit"\nauthor = "Thomas Kluyver"\nmaintainer = "Frost Ming"\n',
+        encoding="utf-8",
+    )
+    result, _ = flit.convert(project, pyproject_file, None)
+
+    assert result["authors"] == [{"name": "Thomas Kluyver"}]
+    assert result["maintainers"] == [{"name": "Frost Ming"}]
+
+
+@pytest.mark.parametrize(
+    "sdist_table,expected_build",
+    [
+        ('include = ["doc/"]', {"includes": ["doc/"]}),
+        ('exclude = ["doc/*.html"]', {"excludes": ["doc/*.html"]}),
+    ],
+)
+def test_convert_flit_sdist_with_one_of_include_and_exclude(project, tmp_path, sdist_table, expected_build):
+    pyproject_file = tmp_path / "pyproject.toml"
+    pyproject_file.write_text(
+        '[tool.flit.metadata]\nmodule = "flit"\nauthor = "Thomas Kluyver"\n'
+        'author-email = "thomas@kluyver.me.uk"\n\n'
+        f"[tool.flit.sdist]\n{sdist_table}\n",
+        encoding="utf-8",
+    )
+    _, settings = flit.convert(project, pyproject_file, None)
+
+    assert settings["build"] == expected_build
+
+
 def test_convert_error_preserve_metadata(project):
     pyproject_file = FIXTURES / "poetry-error.toml"
     try: