From 024e0aef286a717d1c2577a18df408ae7f153b6e Mon Sep 17 00:00:00 2001
From: Arjun Sharma <arjun.sharma07@outlook.com>
Date: Wed, 30 Sep 2026 20:35:04 +0000
Subject: [PATCH] lightspeed: record only files a benchmark's timed body
 executes as its deps

---
 asv/contrib/lightspeed/survey.py |  8 +------
 test/test_lightspeed_survey.py   | 39 ++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 7 deletions(-)
 create mode 100644 test/test_lightspeed_survey.py

diff --git a/asv/contrib/lightspeed/survey.py b/asv/contrib/lightspeed/survey.py
index 5199469d..1ed611f9 100644
--- a/asv/contrib/lightspeed/survey.py
+++ b/asv/contrib/lightspeed/survey.py
@@ -205,13 +205,7 @@ def survey_one(
 
             lines: Set[int] = set(cov_data.lines(fname) or [])
             if not lines:
-                # File was measured but no line-level data — use whole-file
-                # fingerprint so changes to it still trigger re-runs.
-                fp, sha = file_method_checksums(fname)
-                if sha is not None:
-                    file_deps[fname] = (fp, sha)
-                elif uncomputable is None:
-                    uncomputable = fname
+                # With source=, coverage also lists files that never ran; they are not deps of this benchmark.
                 continue
 
             fp, sha = coverage_fingerprint(fname, lines)
diff --git a/test/test_lightspeed_survey.py b/test/test_lightspeed_survey.py
new file mode 100644
index 00000000..94a87ea4
--- /dev/null
+++ b/test/test_lightspeed_survey.py
@@ -0,0 +1,39 @@
+"""survey_one records only the source files a benchmark's timed body executes."""
+
+import sys
+import textwrap
+
+import pytest
+
+pytest.importorskip("coverage")
+from asv.contrib.lightspeed.deps_db import BenchmarkId  # noqa: E402
+from asv.contrib.lightspeed.survey import survey_one  # noqa: E402
+
+
+@pytest.fixture
+def project(tmp_path, monkeypatch):
+    pkg = tmp_path / "pkg"
+    pkg.mkdir()
+    (pkg / "__init__.py").write_text("")
+    (pkg / "used.py").write_text("def work(n):\n    return sum(range(n))\n")
+    (pkg / "unused.py").write_text("def idle():\n    return 0\n")
+    bench = tmp_path / "benchmarks"
+    bench.mkdir()
+    (bench / "__init__.py").write_text("")
+    (bench / "bench_pkg.py").write_text(textwrap.dedent("""
+        import pkg.unused
+        from pkg.used import work
+
+        def time_work():
+            work(1000)
+    """))
+    monkeypatch.syspath_prepend(str(tmp_path))
+    yield tmp_path
+    for name in [m for m in sys.modules if m == "pkg" or m.startswith(("pkg.", "bench_pkg"))]:
+        del sys.modules[name]
+
+
+def test_only_executed_files_are_deps(project):
+    ok, reason, deps = survey_one(str(project / "benchmarks"), BenchmarkId("bench_pkg.time_work"), str(project / "pkg"))
+    assert ok, reason
+    assert {p.split("/pkg/")[-1] for p in deps} == {"used.py"}