Raise error when dims match the variable name (#5518)

* Added assertion that a variable doesn't have the same name as its dimensions.
* Fixed error in tests triggered by var-dim name collision.
Closes #5309

Author: kimbochen

pymc/model.py

@@ -1442,7 +1442,10 @@ def add_random_variable(self, var, dims: Optional[Tuple[Union[str, None], ...]]
         if dims is not None:
             if isinstance(dims, str):
                 dims = (dims,)
-            assert all(dim in self.coords or dim is None for dim in dims)
+            if any(dim not in self.coords and dim is not None for dim in dims):
+                raise ValueError(f"Dimension {dim} is not specified in `coords`.")
+            if any(var.name == dim for dim in dims):
+                raise ValueError(f"Variable `{var.name}` has the same name as its dimension label.")
             self._RV_dims[var.name] = dims
 
         self.named_vars[var.name] = var

pymc/tests/test_idata_conversion.py

@@ -2,6 +2,7 @@
 
 from typing import Dict, Tuple
 
+import aesara.tensor as at
 import numpy as np
 import pandas as pd
 import pytest
@@ -602,6 +603,12 @@ def test_issue_5043_autoconvert_coord_values(self):
             )
             assert isinstance(converter.coords["city"], pd.MultiIndex)
 
+    def test_variable_dimension_name_collision(self):
+        with pytest.raises(ValueError, match="same name as its dimension"):
+            with pm.Model() as pmodel:
+                var = at.as_tensor([1, 2, 3])
+                pmodel.register_rv(var, name="time", dims=("time",))
+
 
 class TestPyMCWarmupHandling:
     @pytest.mark.parametrize("save_warmup", [False, True])

pymc/tests/test_model_graph.py

@@ -104,7 +104,7 @@ def model_with_dims():
 
         population = pm.HalfNormal("population", sd=5, dims=("city"))
 
-        time = pm.ConstantData("year", [2014, 2015, 2016], dims="year")
+        time = pm.ConstantData("time", [2014, 2015, 2016], dims="year")
 
         n = pm.Deterministic(
             "tax revenue", economics * population[None, :] * time[:, None], dims=("year", "city")
@@ -116,15 +116,15 @@ def model_with_dims():
     compute_graph = {
         "economics": set(),
         "population": set(),
-        "year": set(),
-        "tax revenue": {"economics", "population", "year"},
+        "time": set(),
+        "tax revenue": {"economics", "population", "time"},
         "L": {"tax revenue"},
         "observed": {"L"},
     }
     plates = {
         "1": {"economics"},
         "city (4)": {"population"},
-        "year (3)": {"year"},
+        "year (3)": {"time"},
         "year (3) x city (4)": {"tax revenue"},
         "3 x 4": {"L", "observed"},
     }