fix[rust]: melt default value name was wrong in predicate pushdown (#…

…4404)
pola-rs · Aug 14, 2022 · d63c884 · d63c884
1 parent f2829dc
commit d63c884
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Showing 2 changed files with 18 additions and 1 deletion.
diff --git a/polars/polars-lazy/src/logical_plan/optimizer/predicate_pushdown/mod.rs b/polars/polars-lazy/src/logical_plan/optimizer/predicate_pushdown/mod.rs
@@ -210,7 +210,7 @@ impl PredicatePushDown {
                 schema,
             } => {
                 let variable_name = args.variable_name.as_deref().unwrap_or("variable");
-                let value_name = args.value_name.as_deref().unwrap_or("value_name");
+                let value_name = args.value_name.as_deref().unwrap_or("value");
 
                 // predicates that will be done at this level
                 let condition = |name: Arc<str>| {

diff --git a/py-polars/tests/test_filter.py b/py-polars/tests/test_filter.py
@@ -9,3 +9,20 @@ def test_simplify_expression_lit_true_4376() -> None:
     assert df.lazy().filter((pl.col("column_0") == 1) | pl.lit(True)).collect(
         simplify_expression=True
     ).shape == (3, 3)
+
+
+def test_melt_values_predicate_pushdown() -> None:
+    lf = pl.DataFrame(
+        {
+            "id": [1],
+            "asset_key_1": ["123"],
+            "asset_key_2": ["456"],
+            "asset_key_3": ["abc"],
+        }
+    ).lazy()
+
+    assert (
+        lf.melt("id", ["asset_key_1", "asset_key_2", "asset_key_3"])
+        .filter(pl.col("value") == pl.lit("123"))
+        .collect()
+    ).to_dict(False) == {"id": [1], "variable": ["asset_key_1"], "value": ["123"]}