Fix error formatting in C-Elemwise (#1749)

pytensor/tensor/elemwise.py

@@ -1099,7 +1099,7 @@ class Elemwise(OpenMPOp):
         return support_code
 
     def c_code_cache_version_apply(self, node):
-        version = [16]  # the version corresponding to the c code in this Op
+        version = [17]  # the version corresponding to the c code in this Op
 
         # now we insert versions for the ops on which we depend...
         scalar_node = Apply(

pytensor/tensor/elemwise_cgen.py

@@ -85,7 +85,7 @@ def make_checks(loop_orders, dtypes, sub, compute_stride_jump=True):
     runtime_broadcast_error_msg = (
         "Runtime broadcasting not allowed. "
         "One input had a distinct dimension length of 1, but was not marked as broadcastable: "
-        "(input[%%i].shape[%%i] = %%lld, input[%%i].shape[%%i] = %%lld). "
+        "(input[%i].shape[%i] = %lld, input[%i].shape[%i] = %lld). "
         "If broadcasting was intended, use `specify_broadcastable` on the relevant input."
     )
 
@@ -113,7 +113,7 @@ def make_checks(loop_orders, dtypes, sub, compute_stride_jump=True):
                        (long long int) {sub[f"lv{j}"]}_n{x}
                         );
                     }} else {{
-                        PyErr_Format(PyExc_ValueError, "Input dimension mismatch: (input[%%i].shape[%%i] = %%lld, input[%%i].shape[%%i] = %%lld)",
+                        PyErr_Format(PyExc_ValueError, "Input dimension mismatch: (input[%i].shape[%i] = %lld, input[%i].shape[%i] = %lld)",
                            {j0},
                            {x0},
                            (long long int) {sub[f"lv{j0}"]}_n{x0},

tests/tensor/test_elemwise.py

@@ -32,6 +32,7 @@ from pytensor.tensor.type import (
     bmatrix,
     bscalar,
     discrete_dtypes,
+    dmatrix,
     lscalar,
     matrix,
     scalar,
@@ -832,7 +833,26 @@ class TestElemwise(unittest_tools.InferShapeTester):
         reason="G++ not available, so we need to skip this test.",
     )
     def test_runtime_broadcast_c(self):
-        check_elemwise_runtime_broadcast(Mode(linker="c"))
+        c_mode = Mode(linker="cvm")
+        check_elemwise_runtime_broadcast(c_mode)
+
+        # Test C-backend specific error formatting
+        x = dmatrix("x")
+        y = dmatrix("y")
+        fn = function([x, y], x * y, mode=c_mode)
+        with pytest.raises(
+            ValueError,
+            match=r"Runtime broadcasting not allowed.*\(input\[0\]\.shape\[1\] = 4, input\[1\]\.shape\[1\] = 1\)",
+        ):
+            fn(np.zeros((5, 4)), np.zeros((5, 1)))
+
+        with pytest.raises(
+            ValueError,
+            match=re.escape(
+                "Input dimension mismatch: (input[0].shape[1] = 4, input[1].shape[1] = 3)"
+            ),
+        ):
+            fn(np.zeros((5, 4)), np.zeros((5, 3)))
 
     def test_str(self):
         op = Elemwise(ps.add, inplace_pattern={0: 0}, name=None)