fix(gui): reach the file-exists guard from every tab, test exact names

The tabs are handed parent=DataCollectionSettings but
QStackedWidget.addWidget() reparents them to the stack, so the guard's
parent() lookup never found file_path_panel and every Run (rotation,
screening, raster, X-ray centering, Simple) skipped the check. Lookup
now walks up the widget tree; regression test drives all five runs
through the real DataCollectionSettings.

The "taken" test is exact again: <run>_master.h5 plus the DAQ's
derived <run>_raster2d/_raster1d_master.h5. The directory test and the
_*_master.h5 glob are gone: neither is a file a run writes, and they
painted run numbers red that nothing would ever produce.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/aare/gui/panels/file_path_panel.py

@@ -1,4 +1,3 @@
-import glob
 import os
 from datetime import datetime
 from pathlib import Path
@@ -19,6 +18,22 @@ from aare.gui.widgets.title_label import TitleLabel
 ## 5. If sample is registered in the database as manual, it is by default placed in <date>/manual/<sample name>
 
 
+def find_file_path_panel(widget) -> "FilePathPanel | None":
+    """The FilePathPanel that owns ``widget``'s tab, or None outside the GUI.
+
+    Walks up the widget tree: the scan panels are handed parent=DataCollectionSettings
+    but QStackedWidget.addWidget() reparents them to the stack, so a plain
+    parent() lookup finds no file_path_panel and the Run guard is skipped.
+    """
+    w = widget.parent()
+    while w is not None:
+        panel = getattr(w, "file_path_panel", None)
+        if panel is not None:
+            return panel
+        w = w.parent()
+    return None
+
+
 class FilePathPanel(QWidget):
     path_updated = Signal(str)
 
@@ -117,16 +132,16 @@ class FilePathPanel(QWidget):
                 pass
         return str(root / p)
 
+    # Master files a run can produce: plain scans write "<run>_master.h5",
+    # X-ray Centering writes "<run>_raster2d_master.h5" / "<run>_raster1d_master.h5"
+    # (see daq/operations/raster/service.py). Exact names only: a glob or a
+    # directory test marks runs red that nothing will ever write.
+    _MASTER_SUFFIXES = ("_master.h5", "_raster2d_master.h5", "_raster1d_master.h5")
+
     def _exists_for_run(self, expanded_base_with_run: str) -> bool:
         # expanded_base_with_run is the base without scan-kind transforms yet
         effective = self._effective_dataset_base(expanded_base_with_run)
-        # Taken = master file, directory, or any derived dataset of this run:
-        # X-ray centering writes "<run>_raster2d_master.h5", not "<run>_master.h5".
-        return (
-            os.path.exists(f"{effective}_master.h5")
-            or os.path.exists(effective)
-            or bool(glob.glob(f"{effective}_*_master.h5"))
-        )
+        return any(os.path.exists(effective + suffix) for suffix in self._MASTER_SUFFIXES)
 
     def update_filename(self):
         dir_name = self.directory_edit.text()

src/aare/gui/panels/scan_settings_panel.py

@@ -42,6 +42,7 @@ from PySide6.QtWidgets import (
 )
 
 from aare.gui.constants import LOGGER_NAME
+from aare.gui.panels.file_path_panel import find_file_path_panel
 from aare.gui.widgets.message_box import precondition_check
 from aare.gui.widgets.number_line_edit import NumberLineEdit
 
@@ -388,9 +389,9 @@ class ScanSettingsPanel(QWidget):
         ):
             logger.warning("Beamline not ready; user chose not to continue scan")
             return False
-        p = self.parent()
-        if hasattr(p, "file_path_panel"):
-            reply = p.file_path_panel.file_path_error_box(scan_kind=scan_kind)
+        file_path_panel = find_file_path_panel(self)
+        if file_path_panel is not None:
+            reply = file_path_panel.file_path_error_box(scan_kind=scan_kind)
             logger.debug(f"reply from file path panel: {reply}")
             if not reply:
                 logger.warning("Error with file path.")

src/aare/gui/panels/smart_rotation_panel.py

@@ -9,6 +9,7 @@ from PySide6.QtCore import Qt, Signal, Slot
 from PySide6.QtWidgets import QGridLayout, QLabel, QPushButton, QSizePolicy, QSpacerItem, QWidget
 
 from aare.gui.constants import LOGGER_NAME
+from aare.gui.panels.file_path_panel import find_file_path_panel
 from aare.gui.panels.rotation_data_collection import (
     MAX_OMEGA_SPEED_DEG_S,
     MIN_EXP_TIME_S,
@@ -517,7 +518,7 @@ class SimpleRotationSettingsPanel(QWidget):
     def run_measurement(self):
         # Same file-exists guard as the Rotation tab; this panel is not a
         # ScanSettingsPanel, so it has no check_before_run() to inherit.
-        file_path_panel = getattr(self.parent(), "file_path_panel", None)
+        file_path_panel = find_file_path_panel(self)
         if file_path_panel is not None and not file_path_panel.file_path_error_box(
             scan_kind="rotation"
         ):

tests/unit/gui/test_data_collection_settings.py

@@ -547,18 +547,52 @@ def test_a_derived_dataset_counts_as_taken(file_panel, monkeypatch):
     # X-ray centering writes <run>_raster2d_master.h5, not <run>_master.h5.
     from aare.gui.panels import file_path_panel
 
-    _taken(monkeypatch)
-    monkeypatch.setattr(
-        file_path_panel.glob,
-        "glob",
-        lambda pat: ["hit"] if pat.endswith("raster/d/x_001_*_master.h5") else [],
-    )
+    _taken(monkeypatch, "raster/d/x_001_raster2d_master.h5")
     monkeypatch.setattr(file_path_panel.QMessageBox, "warning", lambda *a, **k: None)
 
     assert file_panel.file_path_error_box(scan_kind="raster") is False
     assert file_panel.run_number_edit.value() == 2
 
 
+def test_a_directory_or_a_sibling_run_is_not_taken(file_panel, monkeypatch):
+    # Only the exact master files count; anything else would paint runs red
+    # that nothing will write.
+    _taken(monkeypatch, "raster/d/x_001", "raster/d/x_0011_master.h5", "raster/d/x_001_data.h5")
+    file_panel.set_scan_kind("raster")
+    assert file_panel.file_name_label.styleSheet() == ""
+    assert file_panel.file_path_error_box(scan_kind="raster") is True
+
+
+def test_every_tab_reaches_the_file_guard(settings_panel, monkeypatch):
+    # The tabs live in a QStackedWidget, which reparents them: a parent()
+    # lookup of file_path_panel found nothing and every Run skipped the guard.
+    from aare.gui.panels import scan_settings_panel
+
+    asked = []
+    monkeypatch.setattr(
+        settings_panel.file_path_panel,
+        "file_path_error_box",
+        lambda scan_kind: asked.append(scan_kind) or False,
+    )
+    monkeypatch.setattr(scan_settings_panel, "precondition_check", lambda *a, **k: True)
+    scans = []
+    for panel in (settings_panel.screening, settings_panel.raster):
+        panel._beamline_state = BeamlineStateEnum.SampleAlignment
+    settings_panel.screening.rotation_scan.connect(scans.append)
+    settings_panel.simple.rotation_scan.connect(scans.append)
+    settings_panel.raster.evaluate_grid.connect(lambda: scans.append("grid"))
+    settings_panel.raster.evaluate_grid_auto.connect(lambda: scans.append("auto"))
+
+    settings_panel.screening.run_screening()
+    settings_panel.screening.run_measurement()
+    settings_panel.simple.run_measurement()
+    settings_panel.raster._on_evaluate_clicked()
+    settings_panel.raster._on_evaluate_auto_clicked()
+
+    assert asked == ["screening", "rotation", "rotation", "raster", "raster"]
+    assert scans == []
+
+
 def test_simple_tab_run_is_blocked_by_the_file_guard(qapp):
     from PySide6.QtWidgets import QWidget