[flake8-bugbear] Re-raise all exceptions with proper exception chaining

src/_pytest/_io/terminalwriter.py

@@ -232,17 +232,17 @@ class TerminalWriter:
                 # which may lead to the previous color being propagated to the
                 # start of the expression, so reset first.
                 return "\x1b[0m" + highlighted
-            except pygments.util.ClassNotFound:
+            except pygments.util.ClassNotFound as e:
                 raise UsageError(
                     "PYTEST_THEME environment variable had an invalid value: '{}'. "
                     "Only valid pygment styles are allowed.".format(
                         os.getenv("PYTEST_THEME")
                     )
-                )
-            except pygments.util.OptionError:
+                ) from e
+            except pygments.util.OptionError as e:
                 raise UsageError(
                     "PYTEST_THEME_MODE environment variable had an invalid value: '{}'. "
                     "The only allowed values are 'dark' and 'light'.".format(
                         os.getenv("PYTEST_THEME_MODE")
                     )
-                )
+                ) from e

src/_pytest/config/__init__.py

@@ -1848,13 +1848,13 @@ def parse_warning_filter(
     try:
         action: "warnings._ActionKind" = warnings._getaction(action_)  # type: ignore[attr-defined]
     except warnings._OptionError as e:
-        raise UsageError(error_template.format(error=str(e)))
+        raise UsageError(error_template.format(error=str(e))) from None
     try:
         category: Type[Warning] = _resolve_warning_category(category_)
     except Exception:
         exc_info = ExceptionInfo.from_current()
         exception_text = exc_info.getrepr(style="native")
-        raise UsageError(error_template.format(error=exception_text))
+        raise UsageError(error_template.format(error=exception_text)) from None
     if message and escape:
         message = re.escape(message)
     if module and escape:
@@ -1867,7 +1867,7 @@ def parse_warning_filter(
         except ValueError as e:
             raise UsageError(
                 error_template.format(error=f"invalid lineno {lineno_!r}: {e}")
-            )
+            ) from None
     else:
         lineno = 0
     return action, message, category, module, lineno