Move logging DuplicateFilter to utils, enable it only in __main__

mkdocs/__main__.py

@@ -46,6 +46,10 @@ def _showwarning(message, category, filename, lineno, file=None, line=None):
 
 
 def _enable_warnings():
+    from mkdocs.commands import build
+
+    build.log.addFilter(utils.DuplicateFilter())
+
     warnings.simplefilter('module', DeprecationWarning)
     warnings.showwarning = _showwarning
 

mkdocs/commands/build.py

@@ -17,22 +17,9 @@ from mkdocs.exceptions import Abort, BuildError
 from mkdocs.structure.files import File, Files, InclusionLevel, _set_exclusions, get_files
 from mkdocs.structure.nav import Navigation, get_navigation
 from mkdocs.structure.pages import Page
-
-
-class DuplicateFilter:
-    """Avoid logging duplicate messages."""
-
-    def __init__(self) -> None:
-        self.msgs: set[str] = set()
-
-    def __call__(self, record: logging.LogRecord) -> bool:
-        rv = record.msg not in self.msgs
-        self.msgs.add(record.msg)
-        return rv
-
+from mkdocs.utils import DuplicateFilter  # noqa - legacy re-export
 
 log = logging.getLogger(__name__)
-log.addFilter(DuplicateFilter())
 
 
 def get_context(

mkdocs/utils/__init__.py

@@ -442,6 +442,18 @@ def nest_paths(paths):
     return nested
 
 
+class DuplicateFilter:
+    """Avoid logging duplicate messages."""
+
+    def __init__(self) -> None:
+        self.msgs: set[str] = set()
+
+    def __call__(self, record: logging.LogRecord) -> bool:
+        rv = record.msg not in self.msgs
+        self.msgs.add(record.msg)
+        return rv
+
+
 class CountHandler(logging.NullHandler):
     """Counts all logged messages >= level."""