Fix crash in dynamics due to Fortran standard violation#1448
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mgduda merged 3 commits intoJun 5, 2026
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@kuanchihwang Could you rebase this PR branch off of the |
…nt in atm_srk3 At line 1970 inside the `atm_srk3` time stepping subroutine, if the `DO_PHYSICS` macro is undefined, the `diag_physics` pointer will not be initialized by the call to the `mpas_pool_get_subpool` subroutine, and therefore its pointer association status will remain undefined. However, at line 2250, this pointer is used as an actual argument to call the `atm_compute_dyn_tend` subroutine, which constitutes a Fortran standard violation. Quoted from Fortran 2023, > 15.5.2.4 Argument association > Except in references to intrinsic inquiry functions, a pointer actual argument that > corresponds to a nonoptional nonpointer dummy argument shall be pointer associated with > a target. This bug can lead to a runtime crash for models that use MPAS as a dynamical core (e.g., CAM, CAM-SIMA). Fix this issue by adding the `pointer` attribute to the `diag_physics` dummy argument for the `atm_compute_dyn_tend` subroutine.
Throughout the `atm_compute_dyn_tend` subroutine, the `tend_physics` pointer dummy argument never changes its pointer association status. Add the missing `intent(in)` attribute for better safety.
In Fortran, explicit initialization of a variable implies the `save` attribute, which may have surprising result and is not thread-safe. Avoid doing it to conform to the Fortran best practices.
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I rebased the PR branch against the |
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At line 1970 inside the
atm_srk3time stepping subroutine, if theDO_PHYSICSmacro is undefined, thediag_physicspointer will not be initialized by the call tompas_pool_get_subpool, and therefore its pointer association status will remain undefined.However, at line 2250, this pointer is used as an actual argument to call
atm_compute_dyn_tend, which constitutes a Fortran standard violation.Quoted from Fortran 2023,
This bug can lead to a runtime crash for models that use MPAS as a dynamical core (e.g., CAM, CAM-SIMA).
Fix this issue by adding the
pointerattribute to thediag_physicsdummy argument for theatm_compute_dyn_tendsubroutine.In addition, two one-line changes have also been introduced to better conform to the Fortran best practices.