From 603136f05cf76509ca467ebf0cd78787f96ddc6d Mon Sep 17 00:00:00 2001
From: Sasa Junuzovic <44276455+microsasa@users.noreply.github.com>
Date: Wed, 6 May 2026 14:18:11 -0700
Subject: [PATCH] fix: remove dead code in _build_active_summary (fp.model
 always None)

Remove two instances of dead/misleading code in parser.py:

1. _build_active_summary line 979: simplified
   'model = fp.model or fp.tool_model' to 'model = fp.tool_model'
   since fp.model is invariably None in the active-session path.

2. _build_session_summary_with_meta line 1058: simplified
   'used_config = fp.model is None and fp.tool_model is None' to
   'used_config = fp.tool_model is None' since fp.model is always
   None when no shutdowns exist.

Added a unit test that explicitly documents the invariant: fp.model
is None when no SESSION_SHUTDOWN events exist, and the summary model
is resolved from fp.tool_model directly.

Closes #1202

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 src/copilot_usage/parser.py        |  4 ++--
 tests/copilot_usage/test_parser.py | 37 ++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/src/copilot_usage/parser.py b/src/copilot_usage/parser.py
index f0ed8f87..a18d993e 100644
--- a/src/copilot_usage/parser.py
+++ b/src/copilot_usage/parser.py
@@ -976,7 +976,7 @@ def _build_active_summary(
     events_path: Path | None = None,
 ) -> SessionSummary:
     """Build a :class:`SessionSummary` for a session with no shutdown data."""
-    model = fp.model or fp.tool_model
+    model = fp.tool_model
 
     # Fall back to ~/.copilot/config.json for active sessions
     if model is None:
@@ -1055,7 +1055,7 @@ def _build_session_summary_with_meta(
             used_config_fallback=False,
         )
 
-    used_config = fp.model is None and fp.tool_model is None
+    used_config = fp.tool_model is None
     return _BuildMeta(
         _build_active_summary(fp, name, config_path, events_path=events_path),
         used_config_fallback=used_config,
diff --git a/tests/copilot_usage/test_parser.py b/tests/copilot_usage/test_parser.py
index 76568f72..d7ca8b5a 100644
--- a/tests/copilot_usage/test_parser.py
+++ b/tests/copilot_usage/test_parser.py
@@ -6754,6 +6754,43 @@ def test_active_session_resolves_model_via_first_pass(self, tmp_path: Path) -> N
         assert summary.model == "claude-sonnet-4"
         assert summary.is_active is True
 
+    def test_active_summary_uses_tool_model_directly_without_fp_model(
+        self, tmp_path: Path
+    ) -> None:
+        """Active session model comes from tool_model alone (fp.model is None).
+
+        Confirms that _build_active_summary does not depend on fp.model
+        (which is only set during SESSION_SHUTDOWN processing).  A session
+        with TOOL_EXECUTION_COMPLETE but no SESSION_SHUTDOWN must resolve
+        the model from fp.tool_model.
+        """
+        tool = json.dumps(
+            {
+                "type": "tool.execution_complete",
+                "data": {
+                    "toolCallId": "tc-1",
+                    "model": "gpt-5.1",
+                    "success": True,
+                },
+                "id": "ev-t1",
+                "timestamp": "2026-03-07T10:01:00.000Z",
+            }
+        )
+        p = tmp_path / "s" / "events.jsonl"
+        _write_events(p, _START_EVENT, _USER_MSG, _ASSISTANT_MSG, tool)
+        events = parse_events(p)
+
+        # Confirm the invariant: fp.model is None when no shutdown exists
+        fp = _first_pass(events)
+        assert fp.model is None
+        assert fp.all_shutdowns == ()
+        assert fp.tool_model == "gpt-5.1"
+
+        # The summary model must match tool_model
+        summary = build_session_summary(events, config_path=tmp_path / "no-config.json")
+        assert summary.model == "gpt-5.1"
+        assert summary.is_active is True
+
     def test_malformed_tool_event_skipped(self, tmp_path: Path) -> None:
         """A malformed tool.execution_complete is skipped; next valid one wins."""
         bad_tool = json.dumps(