chore: faster and stricter mypy (#2968)

* chore: faster mypy

This makes mypy around 26% faster from a cold cache.

Signed-off-by: Henry Schreiner <henryfs@princeton.edu>

* chore: enable more mypy error codes

Turn on possibly-undefined, exhaustive-match, and other strict flags, and
fix what they report. Two real bugs: pyodide never set `repaired_wheel`
when it reused a compatible wheel, so the test step failed with a
NameError; the OCI shell read loop spun forever if the shell exited.

Assisted-by: ClaudeCode:claude-opus-5

* test: carry default OCI runtime into podman vfs test config

Podman ignores its usual config files when CONTAINERS_CONF is set, so it
falls back to the first runtime found on PATH. On current GitHub Ubuntu
runner images that is crun 1.14.1, which cannot parse the OCI spec v1.2.x
config that podman 5.8.4 generates ("crun: unknown version specified").
Query the default runtime path and set it in the generated config.

Assisted-by: ClaudeCode:claude-fable-5

* fix: annotate vfs config dict so mypy passes on Linux

mypy on macOS marks the rest of the function unreachable after the
darwin pytest.skip, so the strict index error only appears on Linux.

Assisted-by: ClaudeCode:claude-fable-5

* chore: minor cleanup of variable name

Signed-off-by: Henry Schreiner <henryfs@princeton.edu>

* test: cover container shell exiting during call

Assisted-by: ClaudeCode:claude-opus-5

---------

Signed-off-by: Henry Schreiner <henryfs@princeton.edu>

unit_test/oci_container_test.py

@@ -29,6 +29,7 @@ from cibuildwheel.oci_container import (
 TYPE_CHECKING = False
 if TYPE_CHECKING:
     from collections.abc import Iterator
+    from typing import Any
 
 # Test utilities
 
@@ -84,6 +85,18 @@ def test_no_lf(container_engine: OCIContainerEngineConfig) -> None:
         assert container.call(["printf", "hello"], capture_output=True) == "hello"
 
 
+def test_abnormal_exit(container_engine: OCIContainerEngineConfig) -> None:
+    container = OCIContainer(
+        engine=container_engine, image=DEFAULT_IMAGE, oci_platform=DEFAULT_OCI_PLATFORM
+    )
+    with container:
+        # kill the shell without a newline, so the write below still goes
+        # through the same buffer and the call fails on read, not on write
+        container.bash_stdin.write(b"exit")
+        with pytest.raises(RuntimeError):
+            container.call(["echo", "hello"])
+
+
 def test_debug_info(container_engine: OCIContainerEngineConfig) -> None:
     container = OCIContainer(
         engine=container_engine, image=DEFAULT_IMAGE, oci_platform=DEFAULT_OCI_PLATFORM
@@ -139,6 +152,7 @@ def test_container_removed(container_engine: OCIContainerEngineConfig) -> None:
     ) as container:
         assert container.name is not None
         container_name = container.name
+        docker_containers_listing = ""
         for _ in range(timeout):
             docker_containers_listing = subprocess.run(
                 f"{container.engine.name} container ls",
@@ -330,7 +344,7 @@ def test_podman_vfs(
     # This requires that we write configuration files and point to them
     # with environment variables before we run podman
     # https://github.com/containers/common/blob/main/docs/containers.conf.5.md
-    vfs_containers_conf_data = {
+    vfs_containers_conf_data: dict[str, dict[str, Any]] = {
         "containers": {
             "default_capabilities": [
                 "CHOWN",
@@ -348,6 +362,20 @@ def test_podman_vfs(
         },
         "engine": {"cgroup_manager": "cgroupfs", "events_logger": "file"},
     }
+
+    # Setting CONTAINERS_CONF makes podman ignore its usual config files, so
+    # carry over the default OCI runtime; the fallback found on PATH can be
+    # too old for the OCI spec version podman generates (e.g. Ubuntu 24.04's
+    # crun 1.14.1 with podman 5.x).
+    oci_runtime = subprocess.run(
+        ["podman", "info", "--format", "{{.Host.OCIRuntime.Path}}"],
+        check=True,
+        capture_output=True,
+        text=True,
+    ).stdout.strip()
+    runtime_name = Path(oci_runtime).name
+    vfs_containers_conf_data["engine"]["runtime"] = runtime_name
+    vfs_containers_conf_data["engine"]["runtimes"] = {runtime_name: [oci_runtime]}
     # https://github.com/containers/storage/blob/main/docs/containers-storage.conf.5.md
     storage_root = vfs_path / ".local/share/containers/vfs-storage"
     run_root = vfs_path / ".local/share/containers/vfs-runroot"