Enable verbose logging with --debug (pypa#12710)

This helps ensure that all relevant context is presented when a failure
happens and diagnosis is being done through the use of `--debug`.

Co-authored-by: Pradyun Gedam <[email protected]>
Co-authored-by: Richard Si <[email protected]>

Author: pradyunsg

news/12710.feature.rst

@@ -0,0 +1 @@
+Using ``--debug`` also enables verbose logging.

src/pip/_internal/cli/base_command.py

@@ -172,6 +172,8 @@ def _main(self, args: List[str]) -> int:
 
         # Set verbosity so that it can be used elsewhere.
         self.verbosity = options.verbose - options.quiet
+        if options.debug_mode:
+            self.verbosity = 2
 
         reconfigure(no_color=options.no_color)
         level_number = setup_logging(

tests/unit/test_base_command.py

@@ -107,6 +107,12 @@ def test_handle_pip_version_check_called(mock_handle_version_check: Mock) -> Non
     mock_handle_version_check.assert_called_once()
 
 
+def test_debug_enables_verbose_logs() -> None:
+    cmd = FakeCommand()
+    cmd.main(["fake", "--debug"])
+    assert cmd.verbosity >= 2
+
+
 def test_log_command_success(fixed_time: None, tmpdir: Path) -> None:
     """Test the --log option logs when command succeeds."""
     cmd = FakeCommand()