Update Construct Allocs Ordering

[egc1722]

pyIPCS Pull Request

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Description

Fixed IRX0565E WRNG.LEN.RECORD error when running IPCS subcommands with user-provided SYSEXEC allocations. When SYSEXEC datasets with incompatible formats, FB and VB, are concatenated, REXX fails to read them if the FB format is first.

The z/OS system reads the attributes of the first dataset in the concatenation to establish the Data Control Block. If the first dataset is FB, the system expects all subsequent datasets in that concatenation to be identical in format and size. If the next dataset is VB, z/OS will fail to read it, resulting in an I/O error.

However, if the first dataset is VB then the system can handle FB files without an error.

Implementation

Reversed SYSEXEC concatenation order in subcmd_shell.py:

Changed concatenation from [pyIPCS SYSEXEC] + [User SYSEXEC] to [User SYSEXEC] + [pyIPCS SYSEXEC],
allowing VB datasets to set the concatenation format and FB datasets to be read as VB without errors.

Note that alternative solutions may include:

• Process datasets independently
• Copy before reading: Standardize all files into a single format (e.g., all VB or all FB) into a temporary dataset before processing

Related Issues

None

Were There Tests Added?

None

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Code Checklist

• Ran pytest src/tests to run all tests with full success Most Important!
• Ran internal tests with full success (IBM Employees) Most Important!
• Updated README and/or User Guide with new changes
• New Version Checklist
  • If this is not a new version pull request check box and continue
  • Updated README and pyproject.toml With Latest Version
  • Updated Changelog

Style Checklist

• Refer to Style Guidelines in CONTRIBUTING.md
• Followed Markdown Style Guidelines
• Followed Code Style Guidelines