Fix index handling in mismatch branch to remove side effects and improve maintainability

[AADARSHPUROHIT466]

This patch addresses a maintainability issue in liboctave/array/Array-base.cc
where the index variable j was incremented inside the right-hand operand of
a logical && operator, introducing side effects and violating MISRA/CERT guidelines.

Changes introduced:

• Reset j = 0 before reuse in the mismatch branch.
• Removed side effects from logical && operand by separating increment logic.
• Added explicit bounds check before accessing rhdv.
• Introduced temporary variable rhs_is_empty for clarity.
• Added comments to improve readability and defensive programming practices.

Impact:

• Ensures safe and predictable index handling.
• Prevents potential invalid memory access.
• Improves code readability and maintainability.
• Aligns with MISRA/CERT compliance and passes SonarCloud Quality Gate.

[mmuetzel]

Any reason that you changed this from operator() to operator[]?

[AADARSHPUROHIT466]

I switched from operator() to operator[] because in this context rhdv is already guaranteed to be a flat array, and the explicit bounds check if (j < rhdvl) ensures safe access. Using operator[] avoids the extra overhead of operator() while still maintaining correctness. If consistency with the rest of the codebase is preferred, I can revert to operator().

[mmuetzel]

Ok. I see.

To be honest, I can't recall the reason for that. But if dimension checks can be skipped, typically the xelem member function is used in Octave. Maybe, that could be done here, too.

[AADARSHPUROHIT466]

I’ve updated the code to use xelem(j) as suggested. This provides raw, efficient access after the explicit bounds check and aligns with Octave’s coding style. Please let me know if further adjustments are needed.

[sonarqubecloud]

Quality Gate failed

Failed conditions
D Maintainability Rating on New Code (required ≥ A)

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud