ci: add a check that our event values cannot diverge

See commit 168de89a "eis: sync event codes with libei", this script
should've prevented that issue.

.gitlab-ci.yml

@@ -290,6 +290,17 @@ abicheck@fedora:38:
   only:
     - merge_requests
 
+event-type-check@fedora:38:
+  extends:
+    - .fedora-build@template
+  script:
+    - .gitlab-ci/meson-build.sh --skip-test
+    - .gitlab-ci/check-event-values.py
+  variables:
+    PKG_CONFIG_PATH: $MESON_BUILDDIR/meson-uninstalled
+  only:
+    - merge_requests
+
 minimum-meson@fedora:38:
   extends:
     - .fedora-build@template

.gitlab-ci/check-event-values.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+#
+# Check that the EI_EVENT_FOO and EIS_EVENT_FOO enum values match (for those events that
+# exist in both libraries).
+
+from typing import Iterator
+from pathlib import Path
+import re
+import subprocess
+import tempfile
+
+template = """
+#include <libei.h>
+#include <libeis.h>
+
+@@@
+
+ int main(void) {
+         return 0;
+}
+"""
+assert_template = '_Static_assert(EIS_EVENT_{event} == EI_EVENT_{event}, "Mismatching event types for {event}");'
+
+
+def extract(header: Path, prefix: str) -> Iterator[str]:
+    with open(header) as fd:
+        for line in fd:
+            match = re.match(rf"^\t{prefix}(\w+)", line)
+            if match:
+                yield match[1]
+
+
+if __name__ == "__main__":
+    ei_events = extract(Path("src/libei.h"), prefix="EI_EVENT_")
+    eis_events = extract(Path("src/libeis.h"), prefix="EIS_EVENT_")
+
+    common = set(ei_events) & set(eis_events)
+
+    print("Shared events that need identical values:")
+    for e in common:
+        print(f"  EI_EVENT_{e}")
+
+    asserts = (assert_template.format(event=e) for e in common)
+
+    with tempfile.NamedTemporaryFile(suffix=".c", delete=False) as fd:
+        fd.write(template.replace("@@@", "\n".join(asserts)).encode("utf-8"))
+        fd.flush()
+        pkgconfig = subprocess.run(
+            ["pkg-config", "--cflags", "--libs", "libei-1.0", "libeis-1.0"],
+            check=True,
+            capture_output=True,
+        )
+        pkgconfig_args = pkgconfig.stdout.decode("utf-8").strip().split(" ")
+        try:
+            subprocess.run(
+                ["gcc", "-o", "event-type-check", *pkgconfig_args, fd.name],
+                check=True,
+                capture_output=True,
+            )
+            print("Success. Event types are identical")
+        except subprocess.CalledProcessError as e:
+            print("Mismatching event types")
+            print(e.stdout.decode("utf-8"))
+            print(e.stderr.decode("utf-8"))
+            raise SystemExit(1)

.gitlab-ci/ci.template

@@ -290,6 +290,17 @@ abicheck@{{distro.name}}:{{version}}:
   only:
     - merge_requests
 
+event-type-check@{{distro.name}}:{{version}}:
+  extends:
+    - .{{distro.name}}-build@template
+  script:
+    - .gitlab-ci/meson-build.sh --skip-test
+    - .gitlab-ci/check-event-values.py
+  variables:
+    PKG_CONFIG_PATH: $MESON_BUILDDIR/meson-uninstalled
+  only:
+    - merge_requests
+
 minimum-meson@{{distro.name}}:{{version}}:
   extends:
     - .{{distro.name}}-build@template