ENH: do not generate build-time pins for pre-releases

It is not possible to define a universally useful semantic for
build-time pins involving pre-releases. Do not generate them.

Author: dnicolodi

Diff for: mesonpy/__init__.py

@@ -771,6 +771,9 @@ def _compute_build_time_dependencies(
             version = packaging.version.parse(importlib_metadata.version(name))
         except importlib_metadata.PackageNotFoundError as exc:
             raise ConfigError(f'package "{name}" specified in "build-time-pins" not found: {template!r}') from exc
+        if version.is_devrelease or version.is_prerelease:
+            print('meson-python: build-time pin for pre-release version "{version}" of "{name}" not generared: {template!r}')
+            continue
         pin = packaging.requirements.Requirement(template.format(v=version))
         if pin.marker:
             raise ConfigError(f'requirements in "build-time-pins" cannot contain markers: {template!r}')

Diff for: tests/test_wheel.py

@@ -311,3 +311,29 @@ def test_build_time_pins(wheel_dynamic_dependencies):
             Requires-Dist: meson-python>=0.13.0
             Requires-Dist: packaging~={packaging_version.major}.{packaging_version.minor}
         ''')
+
+
+def test_compute_build_time_dependencies(monkeypatch):
+    versions = {
+        'aaa': '1.2.3',
+        'bbb': '4.5.6',
+        'ddd': '1.0.0rc1', # pre-release will not be added to build-time dependencies
+    }
+    monkeypatch.setattr(importlib_metadata, 'version', lambda package: versions.get(package))
+    deps = [
+        'bbb>=0.1',
+        'ccc>=0.2',
+        'ddd>=0.3',
+    ]
+    pins = [
+        'aaa>={v}',
+        'bbb~={v.major}.{v.minor}',
+        'ddd=={v}',
+    ]
+    r = mesonpy._compute_build_time_dependencies([packaging.requirements.Requirement(x) for x in deps], pins)
+    assert sorted(str(x) for x in r) == [
+        'aaa>=1.2.3',
+        'bbb>=0.1,~=4.5',
+        'ccc>=0.2',
+        'ddd>=0.3',
+    ]