perf: lazy-import vscode_parser and vscode_report in CLI (#890)

src/copilot_usage/cli.py

@@ -35,8 +35,6 @@
     render_summary,
     session_display_name,
 )
-from copilot_usage.vscode_parser import get_vscode_summary
-from copilot_usage.vscode_report import render_vscode_summary
 
 type _View = Literal["home", "detail", "cost"]
 
@@ -661,6 +659,9 @@ def live(ctx: click.Context, path: Path | None) -> None:
 )
 def vscode(vscode_logs: Path | None) -> None:
     """Show usage from VS Code Copilot Chat logs."""
+    from copilot_usage.vscode_parser import get_vscode_summary
+    from copilot_usage.vscode_report import render_vscode_summary
+
     _print_version_header()
     summary = get_vscode_summary(vscode_logs)
     if summary.total_requests == 0:

tests/copilot_usage/test_vscode_parser.py

@@ -859,7 +859,10 @@ def test_all_files_error_shows_correct_message(self) -> None:
         summary = VSCodeLogSummary(
             log_files_found=2, log_files_parsed=0, total_requests=0
         )
-        with patch("copilot_usage.cli.get_vscode_summary", return_value=summary):
+        with patch(
+            "copilot_usage.vscode_parser.get_vscode_summary",
+            return_value=summary,
+        ):
             runner = CliRunner()
             result = runner.invoke(main, ["vscode"])
         assert result.exit_code == 1
@@ -870,7 +873,10 @@ def test_no_files_shows_no_requests_message(self) -> None:
         summary = VSCodeLogSummary(
             log_files_found=0, log_files_parsed=0, total_requests=0
         )
-        with patch("copilot_usage.cli.get_vscode_summary", return_value=summary):
+        with patch(
+            "copilot_usage.vscode_parser.get_vscode_summary",
+            return_value=summary,
+        ):
             runner = CliRunner()
             result = runner.invoke(main, ["vscode"])
         assert result.exit_code == 1

tests/test_packaging.py

@@ -99,3 +99,34 @@ def test_ccreq_re_not_in_vscode_parser_all() -> None:
 
     dunder_all = vscode_mod.__all__
     assert "CCREQ_RE" not in dunder_all, "CCREQ_RE must not be in vscode_parser.__all__"
+
+
+def test_cli_does_not_import_vscode_modules_at_module_level() -> None:
+    """``vscode_parser`` and ``vscode_report`` must be lazy-imported.
+
+    Regression guard for issue #890: these modules are only needed by the
+    ``vscode`` subcommand and should not be imported at ``cli`` module level
+    to avoid loading ``re``, ``stat``, ``types``, and running ``re.compile``
+    on every invocation.
+    """
+    import sys
+
+    original_sys_modules = sys.modules.copy()
+    try:
+        # Purge any previously imported copilot_usage modules so we get a
+        # clean import of cli.
+        for mod_name in list(sys.modules):
+            if mod_name == "copilot_usage" or mod_name.startswith("copilot_usage."):
+                del sys.modules[mod_name]
+
+        importlib.import_module("copilot_usage.cli")
+
+        assert "copilot_usage.vscode_parser" not in sys.modules, (
+            "vscode_parser must not be imported at cli module level"
+        )
+        assert "copilot_usage.vscode_report" not in sys.modules, (
+            "vscode_report must not be imported at cli module level"
+        )
+    finally:
+        sys.modules.clear()
+        sys.modules.update(original_sys_modules)