Warn about stale SAC file when channel has no data

HinetPy/win32.py

@@ -351,6 +351,10 @@ def _extract_channel_sac(
         The extracted SAC file name.
     """
 
+    filename = f"{channel.name}.{channel.component}.{suffix}"
+    if outdir != ".":
+        filename = os.path.join(outdir, filename)
+
     cmd = [
         "win2sac_32",
         winfile,
@@ -376,12 +380,17 @@ def _extract_channel_sac(
                     channel.component,
                     channel.id,
                 )
+                if os.path.exists(filename):
+                    logger.warning(
+                        "No new data for %s.%s (%s), but %s already exists "
+                        "on disk and may be stale.",
+                        channel.name,
+                        channel.component,
+                        channel.id,
+                        filename,
+                    )
                 return None
 
-    filename = f"{channel.name}.{channel.component}.{suffix}"
-    if outdir != ".":
-        filename = os.path.join(outdir, filename)
-
     if os.path.exists(filename):  # some channels have no data
         if suffix == "":  # remove extra dot if suffix is empty
             shutil.move(filename, filename[:-1])

tests/test_stale_file_warning.py

@@ -0,0 +1,74 @@
+"""
+Regression tests for issue #152: stale/missing results reported silently.
+
+Uses a fake Popen so no win2sac_32 binary, account, or network is needed.
+"""
+
+import logging
+import os
+
+from HinetPy import win32
+from HinetPy.channel import Channel
+
+
+def _make_channel():
+    return Channel(
+        id="3e81",
+        name="N.NGUH",
+        component="U",
+        latitude=35.0,
+        longitude=140.0,
+        unit="m/s",
+        gain=1000.0,
+        damping=0.7,
+        period=1.0,
+        preamplification=20.0,
+        lsb_value=0.001,
+    )
+
+
+class _FakeStderr:
+    def __init__(self, text):
+        self._text = text
+
+    def read(self):
+        return self._text.encode()
+
+
+class _FakeProc:
+    """Mimics Popen as used in _extract_channel_sac (context manager)."""
+
+    def __init__(self, text):
+        self.stderr = _FakeStderr(text)
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *args):
+        return False
+
+
+def _fake_popen_no_data(*args, **kwargs):
+    return _FakeProc("Data for channel 3e81 not existed\n")
+
+
+def test_no_data_warns_about_stale_file(tmp_path, monkeypatch, caplog):
+    channel = _make_channel()
+    stale = tmp_path / "N.NGUH.U.SAC"
+    stale.write_text("DATO VIEJO", encoding="utf8")
+    monkeypatch.setattr(win32, "Popen", _fake_popen_no_data)
+    with caplog.at_level(logging.WARNING, logger="HinetPy.win32"):
+        result = win32._extract_channel_sac("dummy.cnt", channel, outdir=str(tmp_path))
+    assert result is None
+    assert any("may be stale" in r.message for r in caplog.records)
+
+
+def test_no_data_without_stale_file_warns_once(tmp_path, monkeypatch, caplog):
+    channel = _make_channel()
+    monkeypatch.setattr(win32, "Popen", _fake_popen_no_data)
+    with caplog.at_level(logging.WARNING, logger="HinetPy.win32"):
+        result = win32._extract_channel_sac("dummy.cnt", channel, outdir=str(tmp_path))
+    assert result is None
+    assert not any("may be stale" in r.message for r in caplog.records)
+    assert any("not exists" in r.message for r in caplog.records)
+    assert not os.path.exists(str(tmp_path / "N.NGUH.U.SAC"))