Improve handling of ResourceWarning from sqlite3.

The patch allows suppressing ResourceWarnings from sqlite3 by
specifying filter in command line with -W option.

Author: andy-slac

CHANGELOG.rst

@@ -2,6 +2,17 @@
 Changelog
 =========
 
+* Improve handling of ResourceWarning from sqlite3.
+
+  The plugin adds warning filter for sqlite3 ``ResourceWarning`` unclosed database (since 6.2.0).
+  It checks if there is already existing plugin for this message by comparing filter regular expression.
+  When filter is specified on command line the message is escaped and does not match an expected message.
+  A check for an escaped regular expression is added to handle this case.
+
+  With this fix one can suppress ``ResourceWarning`` from sqlite3 from command line::
+
+    pytest -W "ignore:unclosed database in <sqlite3.Connection object at:ResourceWarning" ...
+
 7.0.0 (2025-09-09)
 ------------------
 

src/pytest_cov/plugin.py

@@ -17,7 +17,10 @@
 if TYPE_CHECKING:
     from .engine import CovController
 
+# The message is unescaped if it comes from configuration file, and escaped if
+# it comes from command line option (-W) or PYTHONWARNINGS envvar.
 COVERAGE_SQLITE_WARNING_RE = re.compile('unclosed database in <sqlite3.Connection object at', re.I)
+COVERAGE_SQLITE_WARNING_RE2 = re.compile('unclosed\\ database\\ in\\ <sqlite3\\.Connection\\ object\\ at', re.I)
 
 
 def validate_report(arg):
@@ -325,7 +328,7 @@ def pytest_runtestloop(self, session):
 
         # we add default warning configuration to prevent certain warnings to bubble up as errors due to rigid filterwarnings configuration
         for _, message, category, _, _ in warnings.filters:
-            if category is ResourceWarning and message == COVERAGE_SQLITE_WARNING_RE:
+            if category is ResourceWarning and message in (COVERAGE_SQLITE_WARNING_RE, COVERAGE_SQLITE_WARNING_RE2):
                 break
         else:
             warnings.filterwarnings('default', 'unclosed database in <sqlite3.Connection object at', ResourceWarning)