handle missing dual values when barrier solution has no crossover

doc/release_notes.rst

@@ -17,6 +17,7 @@ Upcoming Version
 * Add ``active`` parameter to ``piecewise()`` for gating piecewise linear functions with a binary variable (e.g. unit commitment). Supported for incremental, SOS2, and disjunctive methods.
 * Add the `sphinx-copybutton` to the documentation
 * Add SOS1 and SOS2 reformulations for solvers not supporting them.
+* Improve handling of CPLEX solver quality attributes to ensure metrics such are extracted correctly when available.
 * Fix Xpress IIS label mapping for masked constraints and add a regression test for matching infeasible coordinates.
 * Enable quadratic problems with SCIP on windows.
 

linopy/solvers.py

@@ -1405,14 +1405,16 @@ def get_solver_solution() -> Solution:
                 m.solution.get_values(), m.variables.get_names(), dtype=float
             )
 
-            if is_lp:
+            try:
                 dual = pd.Series(
                     m.solution.get_dual_values(),
                     m.linear_constraints.get_names(),
                     dtype=float,
                 )
-            else:
-                logger.warning("Dual values of MILP couldn't be parsed")
+            except Exception:
+                logger.warning(
+                    "Dual values not available (e.g. barrier solution without crossover)"
+                )
                 dual = pd.Series(dtype=float)
             return Solution(solution, dual, objective)