added some conditionals to help find bug in subplot shapes

Author: zfoltz

debug.py

@@ -0,0 +1,41 @@
+import plotly.express as px
+import plotly.graph_objects as go
+import numpy as np
+from plotly import subplots
+
+test_subplots = True
+use_OP = False
+
+df = px.data.iris()
+if use_OP:
+    fig = px.scatter(df, x="petal_length", y="petal_width")
+    fig.add_traces(go.Scatter(y=np.arange(1, 7), mode="lines+markers", yaxis="y2"))
+
+    fig.update_layout(
+        yaxis2=dict(
+            title="yaxis2 title",
+            overlaying="y",
+            side="right",
+        )
+    )
+else:
+    trace1 = go.Scatter(x=df["petal_length"], y=df["petal_width"], mode="markers")
+    trace2 = go.Scatter(
+        x=[0, 1, 2, 3, 4, 5], y=np.arange(1, 7), mode="lines+markers", yaxis="y2"
+    )
+    data = [trace1, trace2]
+    layout = go.Layout(
+        yaxis=dict(title="yaxis1"),
+        yaxis2=dict(title="yaxis2 title", overlaying="y", side="right"),
+    )
+    fig = go.Figure(data=data, layout=layout)
+if test_subplots:
+    fig = subplots.make_subplots(rows=1, cols=2, shared_yaxes=False)
+
+fig.add_hline(
+    y=2,
+    line_dash="dash",
+    line_color="Red",  # yref='y2'
+    # secondary_y=True
+)
+fig.show()

debugtesting.py

@@ -0,0 +1,43 @@
+import plotly.express as px
+import plotly.graph_objects as go
+import numpy as np
+from plotly.subplots import make_subplots
+
+
+for k, fun, d, fun2, d2 in [
+    (
+        "shapes",
+        go.Figure.add_shape,
+        dict(type="rect", x0=1.5, x1=2.5, y0=3.5, y1=4.5),
+        # add a different type to make the check easier (otherwise we might
+        # mix up the objects added before and after fun was run)
+        go.Figure.add_annotation,
+        dict(x=1, y=2, text="A"),
+    ),
+    (
+        "annotations",
+        go.Figure.add_annotation,
+        dict(x=1, y=2, text="A"),
+        go.Figure.add_layout_image,
+        dict(x=3, y=4, sizex=2, sizey=3, source="test"),
+    ),
+    (
+        "images",
+        go.Figure.add_layout_image,
+        dict(x=3, y=4, sizex=2, sizey=3, source="test"),
+        go.Figure.add_shape,
+        dict(type="rect", x0=1.5, x1=2.5, y0=3.5, y1=4.5),
+    ),
+]:
+    # make a figure where not all the subplots are populated
+    fig = make_subplots(2, 2)
+    fig.add_trace(go.Scatter(x=[1, 2, 3], y=[5, 1, 2]), row=1, col=1)
+    fig.add_trace(go.Scatter(x=[1, 2, 3], y=[2, 1, -7]), row=2, col=2)
+    fun2(fig, d2, row=1, col=2)
+    # add a thing to all subplots but make sure it only goes on the
+    # plots without data or layout objects
+    fun(fig, d, row="all", col="all", exclude_empty_subplots="anything_truthy")
+    assert len(fig.layout[k]) == 3
+    assert fig.layout[k][0]["xref"] == "x" and fig.layout[k][0]["yref"] == "y"
+    assert fig.layout[k][1]["xref"] == "x2" and fig.layout[k][1]["yref"] == "y2"
+    assert fig.layout[k][2]["xref"] == "x4" and fig.layout[k][2]["yref"] == "y4"

packages/python/plotly/plotly/basedatatypes.py

@@ -1567,6 +1567,7 @@ def _add_annotation_like(
                         prop_singular=prop_singular, r=row, c=col
                     )
                 )
+            #'''
             # If the new_object was created with an xref specified, the specified xref should be used otherwise assign the xref from the layout_keys
             if new_obj.xref == None:
                 if secondary_y:
@@ -1585,6 +1586,14 @@ def _add_annotation_like(
                 yref = yaxis.replace("axis", "")
             else:
                 yref = new_obj.yref
+            #'''
+            """
+            if secondary_y:
+                xaxis, yaxis = refs[1].layout_keys
+            else:
+                xaxis, yaxis = refs[0].layout_keys
+            xref, yref = xaxis.replace("axis", ""), yaxis.replace("axis", "")
+            """
             # if exclude_empty_subplots is True, check to see if subplot is
             # empty and return if it is
             if exclude_empty_subplots and (
@@ -4063,10 +4072,12 @@ def _process_multiple_axis_spanning_shapes(
                 # however, in the case of a single plot, xref and yref MAY not be
                 # specified, IF they are not specified we specify them here so the following routines can work
                 # (they need to append " domain" to xref or yref)
-                if self.layout[layout_obj][-1].xref is None:
+                if self.layout[layout_obj][-1].xref == None:
                     self.layout[layout_obj][-1].update(xref="x")
-                if self.layout[layout_obj][-1].yref is None:
+                # self.layout[layout_obj][-1].update(xref="x")
+                if self.layout[layout_obj][-1].yref == None:
                     self.layout[layout_obj][-1].update(yref="y")
+                # self.layout[layout_obj][-1].update(yref='y')
             new_layout_objs = tuple(
                 filter(
                     lambda x: x is not None,