📦🧪 Move Cython translation in CI to backend

.github/workflows/ci-cd.yml

@@ -219,15 +219,13 @@ jobs:
           github.event_name != 'push'
           || !contains(github.ref, 'refs/tags/')
         )
-      run: >
+      env:
+        PYTHONPATH: packaging/
+      run: |
         set -eEuo pipefail
 
-
-        python -Im cython
-        -X linetrace=true
-        -X embedsignature=true
-        -X emit_code_comments=true
-        yarl/*.pyx
+        python -Im pip install expandvars
+        python -m pep517_backend.cli translate-cython
       shell: bash
     - name: Disable the Cython.Coverage Produce plugin
       if: >-  # Only works if the dists were built with line tracing

packaging/pep517_backend/__main__.py

@@ -0,0 +1,6 @@
+import sys
+
+from . import cli
+
+if __name__ == "__main__":
+    sys.exit(cli.run_main_program(argv=sys.argv))

packaging/pep517_backend/cli.py

@@ -0,0 +1,53 @@
+# fmt: off
+
+from __future__ import annotations
+
+import sys
+from itertools import chain
+from pathlib import Path
+
+from Cython.Compiler.Main import compile as _translate_cython_cli_cmd
+from Cython.Compiler.Main import parse_command_line as _split_cython_cli_args
+
+from ._cython_configuration import get_local_cython_config as _get_local_cython_config
+from ._cython_configuration import (
+    make_cythonize_cli_args_from_config as _make_cythonize_cli_args_from_config,
+)
+from ._cython_configuration import patched_env as _patched_cython_env
+
+_PROJECT_PATH = Path(__file__).parents[2]
+
+
+def run_main_program(argv) -> int | str:
+    """Invoke ``translate-cython`` or fail."""
+    if len(argv) != 2:
+        return 'This program only accepts one argument -- "translate-cython"'
+
+    if argv[1] != 'translate-cython':
+        return 'This program only implements the "translate-cython" subcommand'
+
+    config = _get_local_cython_config()
+    config['flags'] = {'keep-going': config['flags']['keep-going']}
+    config['src'] = list(
+        map(
+            str,
+            chain.from_iterable(
+                map(_PROJECT_PATH.glob, config['src']),
+            ),
+        ),
+    )
+    translate_cython_cli_args = _make_cythonize_cli_args_from_config(config)
+
+    cython_options, cython_sources = _split_cython_cli_args(
+        translate_cython_cli_args,
+    )
+
+    with _patched_cython_env(config['env'], cython_line_tracing_requested=True):
+        return _translate_cython_cli_cmd(
+            cython_sources,
+            cython_options,
+        ).num_errors
+
+
+if __name__ == '__main__':
+    sys.exit(run_main_program(argv=sys.argv))