Add _ENCODE_FILE_NEW and _ENCODE_FILE_EXISTING variables

[sabi789]

No description provided.

[augmentcode]

🤖 Augment PR Summary

Summary: This PR extends the z/OS (MVS) Bash port to expose two additional encoding-related special variables.

Changes:

• Adds _ENCODE_FILE_NEW and _ENCODE_FILE_EXISTING to the special_vars table (MVS-only)
• Introduces sv_encode_file_new and sv_encode_file_existing hooks that synchronize these shell variables to same-named environment variables
• Updates variables.h declarations (within __MVS__) for the new hook functions
• Adds an MVS-specific include (<_Nascii.h>) to support the existing autoconversion hook code

Technical Notes: The new hooks aim to influence both child process environments and encoding behavior for file operations on z/OS.

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[augmentcode]

Review completed. 1 suggestion posted.

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[augmentcode]

setenv/unsetenv here may conflict with Bash’s own export_env/environ management (Bash can point environ at an internal buffer), which can lead to stale pointers or child processes not seeing the updated values. Other locations where this applies: stable-patches/variable.patch:68, stable-patches/variable.patch:91, stable-patches/variable.patch:97.

Severity: high

Other Locations

• stable-patches/variable.patch:68
• stable-patches/variable.patch:91
• stable-patches/variable.patch:97

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[IgorTodorovskiIBM]

Do we support _ENCODE_FILE_EXISTING in zoslib now?

[sabi789]

:/home/sabitha/zostools/zopen_sabi/bashport>env | grep _ENCODE_FILE
:/home/sabitha/zostools/zopen_sabi/bashport>export _ENCODE_FILE_NEW=UTF-8
:/home/sabitha/zostools/zopen_sabi/bashport>echo "hello" > newfile3.txt
:/home/sabitha/zostools/zopen_sabi/bashport>ls -T newfile3.txt
t ISO8859-1 T=on -rw-rw-r-- 1 SABITHA SYSPGMR 6 May 6 07:28 newfile3.txt
:/home/sabitha/zostools/zopen_sabi/bashport>env | grep _ENCODE_FILE
_ENCODE_FILE_NEW=UTF-8
:/home/sabitha/zostools/zopen_sabi/bashport>export _ENCODE_FILE_EXISTING=ISO8859-1
:/home/sabitha/zostools/zopen_sabi/bashport>env | grep _ENCODE_FILE
_ENCODE_FILE_EXISTING=ISO8859-1
_ENCODE_FILE_NEW=UTF-8
:/home/sabitha/zostools/zopen_sabi/bashport>ls -T newfile3.txt
t ISO8859-1 T=on -rw-rw-r-- 1 SABITHA SYSPGMR 6 May 6 07:28 newfile3.txt
:/home/sabitha/zostools/zopen_sabi/bashport>cat newfile3.txt
hello
:/home/sabitha/zostools/zopen_sabi/bashport>env | grep _ENCODE_FILE
_ENCODE_FILE_EXISTING=ISO8859-1
_ENCODE_FILE_NEW=UTF-8
:/home/sabitha/zostools/zopen_sabi/bashport>unset _ENCODE_FILE_NEW
:/home/sabitha/zostools/zopen_sabi/bashport>unset _ENCODE_FILE_EXISTING
:/home/sabitha/zostools/zopen_sabi/bashport>env | grep _ENCODE_FILE
:/home/sabitha/zostools/zopen_sabi/bashport>export _ENCODE_FILE_NEW=IBM-1047
:/home/sabitha/zostools/zopen_sabi/bashport>env | grep _ENCODE_FILE
_ENCODE_FILE_NEW=IBM-1047
:/home/sabitha/zostools/zopen_sabi/bashport>echo "hello" > newfile4.txt
:/home/sabitha/zostools/zopen_sabi/bashport>ls -T newfile4.txt
t IBM-1047 T=on -rw-rw-r-- 1 SABITHA SYSPGMR 6 May 6 07:31 newfile4.txt
:/home/sabitha/zostools/zopen_sabi/bashport>cat newfile4.txt
hello
:/home/sabitha/zostools/zopen_sabi/bashport>unset _ENCODE_FILE_NEW