Potential memory leak in ensure_column_capacity due to unsafe realloc usage

[LucasBoTang]

Summary

I found a potential memory leak in ensure_column_capacity when handling realloc failures.

Root cause

In the current implementation, the results of realloc are assigned directly to state->objective_coeffs, state->var_lower_bounds, and state->var_upper_bounds. If one realloc succeeds but a later one fails, the original pointer is lost,
causing a memory leak.

Suggested fix

Use temporary variables for each realloc call, only assign back if all succeed, and free any partially allocated blocks on failure. I implemented a fix in my fork.

Impact

No functional change in normal cases. The fix only improves robustness in low-memory conditions by preventing leaks.

Testing

Pass the test with 2club200v15p5scn.mps.gz instance.

[LucasBoTang]

Now I replaced all uses of realloc with safe_realloc.