Custom lock/rlock classes owning the protected data

[happz]

Compared to the well-known threading.Lock, the locks added here wrap the data they protect. It is still possible to modify the data, since Python does not have actual private attributes, but it's no longer possible to do so by accident or by omission:

# With the classical approach...
_SOME_SHARED_DATA_LOCK = threading.Lock()
SOME_SHARED_DATA = set()

# ... nothing stops me from changing the set without taking the lock:
SOME_SHARED_DATA.add('foo')

# On the other hand, with our custom locks, the set does not exist as
# a value I could modify directly...
SOME_SHARED_DATA: Lock[set[str]] = Lock(set())

# ... and it's "lent" to me only if the wrapper acquires the lock on my
# behalf:
with SOME_SHARED_DATA as the_wrapped_set:
    the_wrapped_set.add('foo')

Pull Request Checklist

• implement the feature
• write the documentation
• extend the test coverage

[LecrisUT]

Is the intent to move all of the treading locks to these and deny the plain threading.Lock usage?

Also is this part of a chain? Could use the context and see some more in-action usage to confirm typing works and all that.

[happz]

Is the intent to move all of the treading locks to these and deny the plain threading.Lock usage?

Eventually, yes.

Also is this part of a chain? Could use the context and see some more in-action usage to confirm typing works and all that.

Mostly drafts, nothing presentable. But the typing works.

diff --git a/tmt/utils/__init__.py b/tmt/utils/__init__.py
index 8663ea655..d8c78ab20 100644
--- a/tmt/utils/__init__.py
+++ b/tmt/utils/__init__.py
@@ -6220,7 +6220,8 @@ def is_url(url: str) -> bool:
 
 
 # Handle the thread synchronization for the `catch_warnings(...)` context manager
-_catch_warning_lock = RLock()
+import tmt.utils._threading
+_catch_warnings = tmt.utils._threading.RLock(warnings.catch_warnings)
 ActionType = Literal['default', 'error', 'ignore', 'always', 'module', 'once']
 
 
@@ -6246,6 +6247,7 @@ def catch_warnings_safe(
             ...
     """
 
-    with _catch_warning_lock, warnings.catch_warnings():
-        warnings.simplefilter(action=action, category=category)
-        yield
+    with _catch_warnings as catch_warnings:
+        with catch_warnings():
+            warnings.simplefilter(action=action, category=category)
+            yield