Read access xml

[mo-marqh]

PR Summary

Sci/Tech Reviewer:
Code Reviewer: @svadams

This change introduces XIOS good practice to the definition of fields to be read within XIOS XML config files.

Specifically, the use of read_access=".TRUE." is recommended for all fields being read.

This is implemented in lfric_apps in different ways, some changes have already been applied to lfric_core to facilitate this, but many XML files are read directly and used by XIOS client programmes, such as lfric_atm

whilst good practice for using XIOS2, the use of read_access=".TRUE." is mandatory for future adoption of XIOS3.
This change is supposed to be fully backwards compatible, but there are problems with a small number of changes, reverted in cca3a53

this should be understood and documented prior to adoption of this change.

If it is fully backwards compatible, then this can be adopted for XIOS2 use and make evaluation and testing of XIOS3 easier.

Note also that there is a change to the memory overhead for a small number of lfric_atm jobs that run in attached mode, on the shared queue on EX1A:

s/24GB/36GB  run_lfric_atm_nwp_gal9_coarse_aero_threaded-C48_MG_ex1a_cce_production-32bit
s/24GB/36GB  run_lfric_atm_nwp_gal9_coarse_aero_threaded-C48_MG_ex1a_cce_fast_debug-32bit
s/24GB/36GB  run_lfric_atm_nwp_gal9_coarse_aero_threaded-C48_MG_ex1a_gnu_fast-debug-32bit
s/36GB/36GB  run_lfric_atm_nwp_gal9_debug-C48_MG_ex1a_cce_full-debug-32bit

see 116d32f
this change commit also requires more justification.

Code Quality Checklist

• I have performed a self-review of my own code
• My code follows the project's style guidelines
• Comments have been included that aid understanding and enhance the readability of the code
• My changes generate no new warnings
• All automated checks in the CI pipeline have completed successfully

Testing

• I have tested this change locally, using the LFRic Apps rose-stem suite
• If any tests fail (rose-stem or CI) the reason is understood and acceptable (e.g. kgo changes)
• I have added tests to cover new functionality as appropriate (e.g. system tests, unit tests, etc.)
• Any new tests have been assigned an appropriate amount of compute resource and have been allocated to an appropriate testing group (i.e. the developer tests are for jobs which use a small amount of compute resource and complete in a matter of minutes)

trac.log

Test Suite Results - lfric_apps - readAccessXML/run3

Suite Information

Item	Value
Suite Name	readAccessXML/run3
Suite User	mark.hedley
Workflow Start	2026-03-05T13:33:40
Groups Run	all

Dependency	Reference	Main Like
casim	MetOffice/casim@2026.03.1	True
jules	MetOffice/jules@2026.03.1	True
lfric_apps	mo-marqh/lfric_apps@readAccessXML	False
lfric_core	MetOffice/lfric_core@2026.03.1	True
moci	MetOffice/moci@2026.03.1	True
SimSys_Scripts	MetOffice/SimSys_Scripts@2026.03.1	True
socrates	MetOffice/socrates@2026.03.1	True
socrates-spectral	MetOffice/socrates-spectral@2026.03.1	True
ukca	MetOffice/ukca@2026.03.1	True

Task Information

✅ succeeded tasks - 1511

Security Considerations

• I have reviewed my changes for potential security issues
• Sensitive data is properly handled (if applicable)
• Authentication and authorisation are properly implemented (if applicable)

Performance Impact

• Performance of the code has been considered and, if applicable, suitable performance measurements have been conducted

AI Assistance and Attribution

• Some of the content of this change has been produced with the assistance of Generative AI tool name (e.g., Met Office Github Copilot Enterprise, Github Copilot Personal, ChatGPT GPT-4, etc) and I have followed the Simulation Systems AI policy (including attribution labels)

Documentation

• Where appropriate I have updated documentation related to this change and confirmed that it builds correctly

PSyclone Approval

• If you have edited any PSyclone-related code (e.g. PSyKAl-lite, Kernel interface, optimisation scripts, LFRic data structure code) then please contact the TCD Team

Sci/Tech Review

• I understand this area of code and the changes being added
• The proposed changes correspond to the pull request description
• Documentation is sufficient (do documentation papers need updating)
• Sufficient testing has been completed

(Please alert the code reviewer via a tag when you have approved the SR)

Code Review

• All dependencies have been resolved
• Related Issues have been properly linked and addressed
• CLA compliance has been confirmed
• Code quality standards have been met
• Tests are adequate and have passed
• Documentation is complete and accurate
• Security considerations have been addressed
• Performance impact is acceptable

[ss421]

@DanStoneMO would you be able to try out this change in JEDI? I don't believe there is a dependency on this update but it would be useful to try it out in case there are issues that we could get help with.

[svadams]

Basically all straightforward changes, there are a couple of xml configurations that I don't think need read access - see my comments on the files

[svadams]

I don't think read access is needed here as this configuration is for writing initial conditions files

[mo-marqh]

agreed & reverted

[mo-marqh]

620c638

[svadams]

I don't think read access is needed here as this configuration is for writing a checkpoint

[mo-marqh]

agreed & reverted

[mo-marqh]

620c638

[thomasmelvin]

This all looks fine to me

[DanStoneMO]

I have a branch with accompanying changes in JEDI. Once this is brought back up to date, I will test and link the PR.