Document and test the presence of readme in project.dynamic

Author: hynek

README.md

@@ -49,7 +49,15 @@ requires = ["hatchling", "hatch-fancy-pypi-readme"]
 build-backend = "hatchling.build"
 ```
 
-Next you must add a `[tool.hatch.metadata.hooks.fancy-pypi-readme]` section.
+Next, you must tell the build system that your readme is dynamic by adding it to the `project.dynamic` list:
+
+```toml
+[project]
+# ...
+dynamic = ["readme"]
+```
+
+Next, you must add a `[tool.hatch.metadata.hooks.fancy-pypi-readme]` section.
 
 Here, you **must** supply a `content-type`.
 Currently, only `text/markdown` and `text/x-rst` are supported.

src/hatch_fancy_pypi_readme/_cli.py

@@ -6,7 +6,7 @@
 
 import sys
 
-from typing import Any, TextIO
+from typing import Any, NoReturn, TextIO
 
 from hatch_fancy_pypi_readme.exceptions import ConfigurationError
 
@@ -15,26 +15,39 @@
 
 
 def cli_run(pyproject: dict[str, Any], out: TextIO) -> None:
+    """
+    Best-effort verify config and print resulting PyPI readme.
+    """
+    is_dynamic = False
+    try:
+        is_dynamic = "readme" in pyproject["project"]["dynamic"]
+    except KeyError:
+        pass
+
+    if not is_dynamic:
+        _fail("You must add 'readme' to 'project.dynamic'.")
+
     try:
         cfg = pyproject["tool"]["hatch"]["metadata"]["hooks"][
             "fancy-pypi-readme"
         ]
     except KeyError:
-        print(
+        _fail(
             "Missing configuration "
             "(`[tool.hatch.metadata.hooks.fancy-pypi-readme]`)",
-            file=sys.stderr,
         )
-        sys.exit(1)
 
     try:
         config = load_and_validate_config(cfg)
     except ConfigurationError as e:
-        print(
+        _fail(
             "Configuration has errors:\n\n"
             + "\n".join(f"- {msg}" for msg in e.errors),
-            file=sys.stderr,
         )
-        sys.exit(1)
 
     print(build_text(config.fragments), file=out)
+
+
+def _fail(msg: str) -> NoReturn:
+    print(msg, file=sys.stderr)
+    sys.exit(1)

tests/conftest.py

@@ -4,7 +4,6 @@
 
 import os
 import shutil
-import sys
 
 from pathlib import Path
 
@@ -19,7 +18,7 @@ def _project_directory_uri(tmp_path):
 
 @pytest.fixture(name="new_project")
 def new_project(project_directory_uri, tmp_path, monkeypatch):
-    shutil.copytree(Path.cwd(), tmp_path / 'plugin')
+    shutil.copytree(Path.cwd(), tmp_path / "plugin")
     project_dir = tmp_path / "my-app"
     project_dir.mkdir()
 

tests/example_pyproject.toml

@@ -6,6 +6,7 @@ build-backend = "hatchling.build"
 [project]
 name = "my-pkg"
 version = "1.0"
+dynamic = ["readme"]
 
 
 [tool.hatch.metadata.hooks.fancy-pypi-readme]

tests/test_cli.py

@@ -24,10 +24,12 @@ def _pyproject():
 @pytest.fixture(name="empty_pyproject")
 def _empty_pyproject():
     return {
-        "tool": {"hatch": {"metadata": {"hooks": {"fancy-pypi-readme": {}}}}}
+        "project": {"dynamic": ["foo", "readme", "bar"]},
+        "tool": {"hatch": {"metadata": {"hooks": {"fancy-pypi-readme": {}}}}},
     }
 
 
+@pytest.mark.slow
 class TestCLIEndToEnd:
     @pytest.mark.usefixtures("new_project")
     def test_missing_config(self):
@@ -68,13 +70,26 @@ def test_ok_redirect(self, tmp_path):
 
 
 class TestCLI:
-    @pytest.mark.usefixtures("new_project")
+    def test_cli_run_missing_dynamic(self, capfd):
+        """
+        Missing readme in dynamic is caught and gives helpful advice.
+        """
+        with pytest.raises(SystemExit):
+            cli_run({}, sys.stdout)
+
+        out, err = capfd.readouterr()
+
+        assert "You must add 'readme' to 'project.dynamic'.\n" == err
+        assert "" == out
+
     def test_cli_run_missing_config(self, capfd):
         """
         Missing configuration is caught and gives helpful advice.
         """
         with pytest.raises(SystemExit):
-            cli_run({}, sys.stdout)
+            cli_run(
+                {"project": {"dynamic": ["foo", "readme", "bar"]}}, sys.stdout
+            )
 
         out, err = capfd.readouterr()