AliRana30 commented on PR #49105:
URL: https://github.com/apache/arrow/pull/49105#issuecomment-3842136372

   @raulcd This change fixes a segmentation fault that occurs when comparing
   `SparseCSFIndex` objects with mismatched dimensions.
   
   **Bug description:**  
   The original implementation calls `indices()[i]->Equals(...)` without first
   verifying that both objects have the same number of dimensions. When 
comparing,
   for example, a 2D index with a 3D index:
   
   - `indices().size()` returns different values (e.g., 2 vs 3)
   - The loop iterates using the size of the first object
   - Accessing `other.indices()[i]` with mismatched sizes results in 
out-of-bounds access, leading to a segmentation fault
   
   **Fix:**  
   Lines 408–416 add early size checks before any iteration:
   
   ```cpp
   if (indices().size() != other.indices().size()) return false;
   if (indptr().size() != other.indptr().size()) return false;
   if (axis_order().size() != other.axis_order().size()) return false;
   ```
   
   These checks ensure that Equals safely returns false when dimensions do not 
match, preventing access to invalid memory.
   
   **Test coverage:**
   Added TestEqualityMismatchedDimensions (lines 1644–1661), which reproduces 
theoriginal issue. Without this fix, the test would crash due to the 
segmentation fault.
   


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