From 9236cf1a183418f4f4d03d5f3cc85c7310665f6b Mon Sep 17 00:00:00 2001
From: Alex Lubbock <code@alexlubbock.com>
Date: Sun, 26 Apr 2026 13:17:55 +0100
Subject: [PATCH] fix(resource-usage): forward pre/post_run_triggers via
 super() for correct MRO chaining

---
 CHANGELOG.md                |  8 ++++++++
 microbench/mixins/system.py |  6 ++++++
 tests/test_mixins.py        | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f596a5e..a566de5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -41,6 +41,14 @@ All notable changes to microbench are documented here.
   overrides the default entirely; the Python API is unaffected. The hash
   algorithm name is now stored under `mb.file_hash_algorithm`.
 
+### Bug fixes
+
+- **`MBResourceUsage` — `pre_run_triggers`/`post_run_triggers` now forward
+  via `super()`**: composing `MBResourceUsage` with another mixin that also
+  implements `pre_run_triggers` or `post_run_triggers` previously caused the
+  second mixin's hooks to be silently skipped. Both methods now propagate
+  correctly through the MRO.
+
 ### Documentation
 
 - Fix documentation on writing custom mixins to note that they must be
diff --git a/microbench/mixins/system.py b/microbench/mixins/system.py
index 3971745..5896525 100644
--- a/microbench/mixins/system.py
+++ b/microbench/mixins/system.py
@@ -445,6 +445,9 @@ def pre_run_triggers(self, bm_data):
             self._rusage_iter_before = _rusage_to_dict(
                 _resource.getrusage(_resource.RUSAGE_SELF), include_maxrss=False
             )
+        parent = super()
+        if hasattr(parent, 'pre_run_triggers'):
+            parent.pre_run_triggers(bm_data)
 
     def post_run_triggers(self, bm_data):
         if _resource is not None and not hasattr(self, '_subprocess_command'):
@@ -454,6 +457,9 @@ def post_run_triggers(self, bm_data):
             self._rusage_iter_entries.append(
                 _rusage_delta(self._rusage_iter_before, after)
             )
+        parent = super()
+        if hasattr(parent, 'post_run_triggers'):
+            parent.post_run_triggers(bm_data)
 
     def capturepost_resource_usage(self, bm_data):
         """Write the resource_usage list to bm_data after all iterations."""
diff --git a/tests/test_mixins.py b/tests/test_mixins.py
index 8567046..77d29a1 100644
--- a/tests/test_mixins.py
+++ b/tests/test_mixins.py
@@ -1009,3 +1009,38 @@ def noop():
         _sys_mod._resource = original
 
     assert 'resource_usage' not in bench.get_results()[0]
+
+
+@pytest.mark.skipif(
+    sys.platform == 'win32', reason='resource module not available on Windows'
+)
+def test_resource_usage_run_trigger_chain():
+    """pre/post_run_triggers forward via super() so composed mixins all fire."""
+    calls = []
+
+    class _TrackerMixin:
+        def pre_run_triggers(self, bm_data):
+            calls.append('pre')
+            parent = super()
+            if hasattr(parent, 'pre_run_triggers'):
+                parent.pre_run_triggers(bm_data)
+
+        def post_run_triggers(self, bm_data):
+            calls.append('post')
+            parent = super()
+            if hasattr(parent, 'post_run_triggers'):
+                parent.post_run_triggers(bm_data)
+
+    class Bench(MicroBench, _TrackerMixin, MBResourceUsage):
+        pass
+
+    bench = Bench()
+
+    @bench
+    def noop():
+        pass
+
+    noop()
+
+    assert calls == ['pre', 'post']
+    assert len(bench.get_results()[0]['resource_usage']) == 1