fix(omny): make correction data global-var-backed, fix default file path

Two real bugs found while investigating a recurring AttributeError:
'OMNY' object has no attribute 'corr_pos_x' from tomo_scan_projection().

1. default_correction_file/default_correction_file_x were bare relative
   filenames ("correction_omny_202204.txt"), unlike flomni's equivalent
   which resolves an absolute path via Path(csaxs_bec.__file__). open()
   would only ever succeed if bec were launched from this exact plugin
   directory -- silently swallowed everywhere else by the existing
   FileNotFoundError handler in reset_correction(). The real correction
   files genuinely exist on disk next to the plugin code and were very
   likely never actually being loaded.

2. corr_pos_x/corr_angle_x/corr_pos_y/corr_angle_y/corr_pos_y_2/
   corr_angle_y_2 were plain instance attributes, only ever assigned
   inside reset_correction() (itself only called from
   otransfer_put_sample() during a sample transfer) -- hence the
   AttributeError when calling tomo_scan_projection() beforehand.
   Converted to global-var-backed properties defaulting to [] when unset,
   mirroring flomni's corr_pos_y/corr_angle_y/etc. exactly. This
   supersedes a shallower getattr()-based band-aid from an earlier,
   uncommitted attempt at this fix. As a bonus, correction data now
   persists across BEC client restarts, same as flomni's.

Note flomni has no x-correction concept at all (only corr_pos_y/
corr_pos_y_2) -- omny's x-correction is its own thing, not something
copied from flomni.

17 new/updated tests in test_omny_alignment_mixin.py, including an
end-to-end check that reset_correction(use_default_correction=True) now
actually loads the real correction_omny_202204*.txt files.

csaxs_bec/bec_ipython_client/plugins/omny/omny_alignment_mixin.py

@@ -1,6 +1,7 @@
 import time
 import numpy as np
 import os
+from pathlib import Path
 
 from rich import box
 from rich.console import Console
@@ -17,8 +18,87 @@ class OMNYAlignmentError(Exception):
 
 
 class OMNYAlignmentMixin:
-    default_correction_file = "correction_omny_202204.txt"
-    default_correction_file_x = "correction_omny_202204_x.txt"
+    # Resolved to an absolute path (mirrors Flomni's default_correction_file
+    # setup) -- a bare relative filename would only ever be found if bec were
+    # launched from this exact plugin directory, silently failing (caught by
+    # the FileNotFoundError handler below) everywhere else.
+    import csaxs_bec
+
+    _csaxs_bec_basepath = Path(csaxs_bec.__file__).parent
+    default_correction_file = (
+        _csaxs_bec_basepath
+        / "bec_ipython_client"
+        / "plugins"
+        / "omny"
+        / "correction_omny_202204.txt"
+    ).resolve()
+    default_correction_file_x = (
+        _csaxs_bec_basepath
+        / "bec_ipython_client"
+        / "plugins"
+        / "omny"
+        / "correction_omny_202204_x.txt"
+    ).resolve()
+    del csaxs_bec
+
+    # additional x/y-correction curves: global-var-backed so they survive a
+    # BEC client restart, same pattern as every other persistent setting in
+    # this class (and matching Flomni's corr_pos_y/corr_angle_y/etc.). NOTE:
+    # must NOT be pre-assigned in OMNY.__init__ -- doing so would overwrite
+    # the persisted value with [] on every restart.
+    @property
+    def corr_pos_x(self):
+        val = self.client.get_global_var("corr_pos_x")
+        return [] if val is None else val
+
+    @corr_pos_x.setter
+    def corr_pos_x(self, val: list):
+        self.client.set_global_var("corr_pos_x", val)
+
+    @property
+    def corr_angle_x(self):
+        val = self.client.get_global_var("corr_angle_x")
+        return [] if val is None else val
+
+    @corr_angle_x.setter
+    def corr_angle_x(self, val: list):
+        self.client.set_global_var("corr_angle_x", val)
+
+    @property
+    def corr_pos_y(self):
+        val = self.client.get_global_var("corr_pos_y")
+        return [] if val is None else val
+
+    @corr_pos_y.setter
+    def corr_pos_y(self, val: list):
+        self.client.set_global_var("corr_pos_y", val)
+
+    @property
+    def corr_angle_y(self):
+        val = self.client.get_global_var("corr_angle_y")
+        return [] if val is None else val
+
+    @corr_angle_y.setter
+    def corr_angle_y(self, val: list):
+        self.client.set_global_var("corr_angle_y", val)
+
+    @property
+    def corr_pos_y_2(self):
+        val = self.client.get_global_var("corr_pos_y_2")
+        return [] if val is None else val
+
+    @corr_pos_y_2.setter
+    def corr_pos_y_2(self, val: list):
+        self.client.set_global_var("corr_pos_y_2", val)
+
+    @property
+    def corr_angle_y_2(self):
+        val = self.client.get_global_var("corr_angle_y_2")
+        return [] if val is None else val
+
+    @corr_angle_y_2.setter
+    def corr_angle_y_2(self, val: list):
+        self.client.set_global_var("corr_angle_y_2", val)
 
     def reset_correction(self, use_default_correction=True):
         """
@@ -215,6 +295,10 @@ class OMNYAlignmentMixin:
         return self._compute_additional_correction(angle, iteration="y2")
 
     def _compute_additional_correction(self, angle, iteration="y1"):
+        # corr_pos_x/corr_pos_y/corr_pos_y_2 etc. are global-var-backed
+        # properties that default to [] -- never AttributeError, even before
+        # reset_correction() has ever run (e.g. testing scan mechanics before
+        # any sample transfer).
         if iteration == "x1":
             corr_pos = self.corr_pos_x
             corr_angle = self.corr_angle_x

tests/tests_bec_ipython_client/test_omny_alignment_mixin.py

@@ -0,0 +1,143 @@
+"""Regression test for OMNYAlignmentMixin's correction data.
+
+corr_pos_x/corr_angle_x/corr_pos_y/etc. used to be plain instance attributes,
+only ever assigned inside reset_correction() -- calling
+_compute_additional_correction() before reset_correction() had ever run (e.g.
+tomo_scan_projection() called to test scan mechanics without first doing a
+sample transfer, the only place reset_correction() gets called, see
+omny_sample_transfer_mixin.py's otransfer_put_sample()) raised
+'OMNY' object has no attribute 'corr_pos_x'.
+
+They are now global-var-backed properties (mirroring Flomni's
+corr_pos_y/corr_angle_y/etc.), defaulting to [] when unset -- matching the
+graceful "no data available" handling _compute_additional_correction()
+already had for an empty (but present) list, and persisting across BEC
+client restarts like every other setting in this class.
+
+Also regression-guards default_correction_file/default_correction_file_x
+being resolved to an absolute path (a bare relative filename would only ever
+be found if bec were launched from this exact plugin directory).
+"""
+
+import os
+
+import pytest
+
+from csaxs_bec.bec_ipython_client.plugins.omny.omny_alignment_mixin import OMNYAlignmentMixin
+
+
+class FakeClient:
+    """Minimal in-memory stand-in for BEC's global-var store."""
+
+    def __init__(self):
+        self._vars = {}
+
+    def get_global_var(self, key):
+        return self._vars.get(key)
+
+    def set_global_var(self, key, value):
+        self._vars[key] = value
+
+
+def make_alignment():
+    # bare instance, deliberately never calling reset_correction() -- mirrors
+    # a fresh OMNY session where no sample has been transferred in yet
+    align = OMNYAlignmentMixin()
+    align.client = FakeClient()
+    return align
+
+
+def test_default_correction_files_are_absolute_and_exist():
+    assert os.path.isabs(OMNYAlignmentMixin.default_correction_file)
+    assert os.path.isabs(OMNYAlignmentMixin.default_correction_file_x)
+    assert os.path.exists(OMNYAlignmentMixin.default_correction_file)
+    assert os.path.exists(OMNYAlignmentMixin.default_correction_file_x)
+
+
+@pytest.mark.parametrize(
+    "attr",
+    ["corr_pos_x", "corr_angle_x", "corr_pos_y", "corr_angle_y", "corr_pos_y_2", "corr_angle_y_2"],
+)
+def test_correction_properties_default_to_empty_list(attr):
+    align = make_alignment()
+
+    assert getattr(align, attr) == []
+
+
+@pytest.mark.parametrize("iteration", ["x1", "y1", "y2"])
+def test_compute_additional_correction_returns_zero_when_never_reset(iteration, capsys):
+    align = make_alignment()
+
+    result = align._compute_additional_correction(45.0, iteration=iteration)
+
+    assert result == 0
+    assert "No data available" in capsys.readouterr().out
+
+
+def test_compute_additional_correction_x_does_not_raise():
+    align = make_alignment()
+
+    assert align.compute_additional_correction_x(0.0) == 0
+
+
+def test_compute_additional_correction_y_does_not_raise():
+    align = make_alignment()
+
+    assert align.compute_additional_correction_y(0.0) == 0
+
+
+def test_compute_additional_correction_y_2_does_not_raise():
+    align = make_alignment()
+
+    assert align.compute_additional_correction_y_2(0.0) == 0
+
+
+def test_compute_additional_correction_still_works_after_reset():
+    """Once corr_pos_x/corr_angle_x etc. are actually set (mirrors what
+    reset_correction() -> read_additional_correction_x() would do), the
+    normal closest-angle lookup still works."""
+    align = make_alignment()
+    align.corr_pos_x = [1.0, 2.0, 3.0]
+    align.corr_angle_x = [0.0, 90.0, 180.0]
+
+    result = align._compute_additional_correction(85.0, iteration="x1")
+
+    assert result == 2.0
+
+
+def test_correction_properties_persist_across_instances_via_shared_client():
+    """Global-var-backed: two instances sharing the same client see the same
+    value, unlike a plain instance attribute."""
+    client = FakeClient()
+    align_a = OMNYAlignmentMixin()
+    align_a.client = client
+    align_b = OMNYAlignmentMixin()
+    align_b.client = client
+
+    align_a.corr_pos_x = [5.0]
+
+    assert align_b.corr_pos_x == [5.0]
+
+
+def test_reset_correction_with_default_loads_real_file_data():
+    """End-to-end check of the path-resolution fix: reset_correction(True)
+    must actually find and load the real correction_omny_202204*.txt files
+    (previously silently failed everywhere except when bec happened to be
+    launched from this exact plugin directory)."""
+    align = make_alignment()
+
+    align.reset_correction(use_default_correction=True)
+
+    assert len(align.corr_pos_x) > 0
+    assert len(align.corr_pos_y) > 0
+
+
+def test_reset_correction_without_default_clears_to_empty():
+    align = make_alignment()
+    align.corr_pos_x = [1.0]
+    align.corr_angle_x = [0.0]
+
+    align.reset_correction(use_default_correction=False)
+
+    assert align.corr_pos_x == []
+    assert align.corr_angle_x == []