fix plot having multiple x fields

Author: mattseddon

dvc/render/converter/vega.py

@@ -204,11 +204,13 @@ def flat_datapoints(self, revision):  # noqa: C901, PLR0912
             )
         else:
             x_file, x_field = xs[0]
-        props_update["x"] = x_field
+
+        num_xs = len(xs)
+        unify_x_fields = num_xs > 1 and len({x[1] for x in xs}) > 1
+        props_update["x"] = "dvc_inferred_x_value" if unify_x_fields else x_field
 
         ys = list(_get_ys(properties, file2datapoints))
 
-        num_xs = len(xs)
         num_ys = len(ys)
         if num_xs > 1 and num_xs != num_ys:
             raise DvcException(
@@ -264,8 +266,9 @@ def flat_datapoints(self, revision):  # noqa: C901, PLR0912
                 try:
                     _update_from_field(
                         datapoints,
-                        field=x_field,
+                        field="dvc_inferred_x_value" if unify_x_fields else x_field,
                         source_datapoints=x_datapoints,
+                        source_field=x_field,
                     )
                 except IndexError:
                     raise DvcException(  # noqa: B904

tests/unit/render/test_vega_converter.py

@@ -410,6 +410,107 @@ def test_finding_lists(dictionary, expected_result):
             },
             id="multi_file_y_same_prefix",
         ),
+        pytest.param(
+            {
+                "f": {"metric": [{"x1": 1, "v": 0.1}]},
+                "f2": {"metric": [{"x2": 100, "v": 0.1}]},
+            },
+            {"y": {"f": ["v"], "f2": ["v"]}, "x": {"f": "x1", "f2": "x2"}},
+            [
+                {
+                    "x1": 1,
+                    "v": 0.1,
+                    "dvc_inferred_x_value": 1,
+                    REVISION: "r",
+                    FILENAME: "f",
+                    FIELD: "v",
+                },
+                {
+                    "x2": 100,
+                    "v": 0.1,
+                    "dvc_inferred_x_value": 100,
+                    REVISION: "r",
+                    FILENAME: "f2",
+                    FIELD: "v",
+                },
+            ],
+            {
+                "anchors_y_definitions": [
+                    {FILENAME: "f", FIELD: "v"},
+                    {FILENAME: "f2", FIELD: "v"},
+                ],
+                "x": "dvc_inferred_x_value",
+                "y": "v",
+                "x_label": "x",
+                "y_label": "v",
+            },
+            id="multiple_x_fields",
+        ),
+        pytest.param(
+            {
+                "f": {
+                    "metric": [
+                        {"v": 1, "v2": 0.1, "x1": 100},
+                        {"v": 2, "v2": 0.2, "x1": 1000},
+                    ]
+                },
+                "f2": {"metric": [{"x2": -2}, {"x2": -4}]},
+            },
+            {"y": ["v", "v2"], "x": {"f": "x1", "f2": "x2"}},
+            [
+                {
+                    "dvc_inferred_x_value": 100,
+                    "dvc_inferred_y_value": 1,
+                    "v": 1,
+                    "v2": 0.1,
+                    "x1": 100,
+                    REVISION: "r",
+                    FILENAME: "f",
+                    FIELD: "v",
+                },
+                {
+                    "dvc_inferred_x_value": 1000,
+                    "dvc_inferred_y_value": 2,
+                    "v": 2,
+                    "v2": 0.2,
+                    "x1": 1000,
+                    REVISION: "r",
+                    FILENAME: "f",
+                    FIELD: "v",
+                },
+                {
+                    "dvc_inferred_x_value": -2,
+                    "dvc_inferred_y_value": 0.1,
+                    "v": 1,
+                    "v2": 0.1,
+                    "x1": 100,
+                    REVISION: "r",
+                    FILENAME: "f",
+                    FIELD: "v2",
+                },
+                {
+                    "dvc_inferred_x_value": -4,
+                    "dvc_inferred_y_value": 0.2,
+                    "v": 2,
+                    "v2": 0.2,
+                    "x1": 1000,
+                    REVISION: "r",
+                    FILENAME: "f",
+                    FIELD: "v2",
+                },
+            ],
+            {
+                "anchors_y_definitions": [
+                    {FILENAME: "f", FIELD: "v"},
+                    {FILENAME: "f", FIELD: "v2"},
+                ],
+                "x": "dvc_inferred_x_value",
+                "y": "dvc_inferred_y_value",
+                "x_label": "x",
+                "y_label": "y",
+            },
+            id="y_list_x_dict",
+        ),
     ],
 )
 def test_convert(