[MarcZX10]

What

Updates non-secure guest wide printf formatting to match the measured literal-text behavior for %q, %D/%O/%U, unknown conversions, and width handling observed from libSceLibcInternal.sprx on firmware 12.70. The probe called swprintf from a payload process; it did not exercise a title or its bundled libc.prx, whose Dinkumware _Printf behavior remains unverified. The probe also showed that a trailing % read past the format terminator, so incomplete conversions continue to fail safely. The secure snwprintf_s path continues to reject these forms because its console behavior was not measured.

The original implementation commits retain Hussein Kadhim as author, and the original test commits retain MarcZX100. The review follow-up is authored by MarcZX10.

Tested

• Rebased all six commits onto current upstream main at 661f8b71718083fbac1c45b44f5d67dc39cb4624, preserving their original authorship. The debt-file conflict was resolved by retaining unrelated current-main entries and the PR's measured-versus-extrapolated distinction.
• On the rebased head, python3 tools/check_conventions.py --base upstream/main --head HEAD and git diff --check upstream/main...HEAD pass.
• The prior head 06bd246798 built guest_wide_formatting_tests and passed ctest -R guest_wide_formatting --output-on-failure (1/1). That runtime test was not rerun after the current-main rebase.
• No title libc.prx runtime test, Windows build or full test suite was run.

Checklist

• Based on current main; no other open PR implements the same wide-format functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw; silent stubs are listed under technical debt
• No notes, investigation .md files or images added to the repository
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: none
• Unblocks: none
• GPUs tested: n/a
• AI-assisted: yes

[oneandonlydean]

Which title prints %q, %D/%O/%U, an unknown conversion or a trailing % through the wide printf family? The source here is FreeBSD 11.4, but the console's libc.prx formats through Dinkumware's _Printf, which can handle unknown conversions and q differently (same question as the review on #3987). Until a title reaches it, or _Printf in a title's libc.prx confirms these cases, main's throw is the safer behaviour.

[MarcZX10]

I do not have title traces or Dinkumware _Printf evidence for these wide-format cases. The current evidence is FreeBSD 11.4 behavior and Linux-side tests, so I cannot claim console compatibility for %q, %D/%O/%U, unknown conversions, or a trailing %. I agree this leaves the added behavior unverified against the console; absent title or _Printf evidence, main’s throw is safer. I will avoid presenting these cases as title-required until we have that evidence.

[adriadam10]

Thanks for the fix. Blocking points:

• The console's libc.prx formats through Dinkumware's _Printf, not FreeBSD's vfwprintf. As discussed above, neither a title nor _Printf evidence shows that %q, %D/%O/%U, unknown conversions (with width) or a trailing % behave as FreeBSD 11.4 does there; main's throw is the safe behaviour until then. Evidence that would unblock it: the relevant branches of _Printf disassembled from a title's libc.prx (same approach as in #3987), or a title that reaches these cases.
• Once evidence exists, the branch conflicts with main in core/libs/tests/GuestWideFormatting.cpp; it needs a rebase.

[github-actions]

Other open pull requests touch the same code. Merging one will break the other, or both implement the same thing. If this one builds on them, list them in Depends on.

Pull request	Conflicting files (lines on main)	Same exports	Same new files
PR 7386	docs/dev/debt/libc.md L143-144
PR 9340	docs/dev/debt/libc.md L143-144
PR 9364	docs/dev/debt/libc.md L143

Some comparisons could not be completed because a pull request conflicts with the base branch. Review these shared files manually before concluding that there is no overlap.

Pull request	Shared files not compared
PR 3965	docs/dev/debt/libc.md
PR 5021	docs/dev/debt/libc.md
PR 7544	docs/dev/debt/libc.md
PR 7715	docs/dev/debt/libc.md
PR 8150	docs/dev/debt/libc.md
PR 8417	docs/dev/debt/libc.md
PR 9133	docs/dev/debt/libc.md
PR 9170	docs/dev/debt/libc.md
PR 9371	docs/dev/debt/libc.md
PR 9447	docs/dev/debt/libc.md
PR 9526	docs/dev/debt/libc.md
PR 9527	core/libs/prx/libc/src/FormattingWide.cpp docs/dev/debt/libc.md
PR 9552	docs/dev/debt/libc.md
PR 9669	docs/dev/debt/libc.md
PR 9863	docs/dev/debt/libc.md
PR 9873	docs/dev/debt/libc.md
PR 9929	docs/dev/debt/libc.md

[MarcZX10]

Thanks for the firmware 12.70 payload report. The current PR head already follows the measured literal handling for the reported non-secure wide swprintf cases and explicitly limits its claim to libSceLibcInternal.sprx, not a title’s bundled libc.prx. Your trailing-percent probe shows an out-of-bounds read, so it does not support a deterministic output; the implementation continues to reject an incomplete conversion. I found no additional code change justified by this report. The open title _Printf evidence/rebase review point remains as stated in the latest review.

[MarcZX10]

Rebased the six existing commits onto current upstream main 661f8b71718083fbac1c45b44f5d67dc39cb4624, preserving their original authors. The debt-file conflict retained current-main entries and the PR’s distinction between measured and extrapolated payload behavior. Conventions and git diff --check pass on new head f52d991a2d; the focused Linux 1/1 formatting test passed on the prior head 06bd246798 and has not been rerun after this rebase. No claim is made for title libc.prx behavior or Windows/full-suite validation.

[MarcZX10]

Final hosted check update for head f52d991a2df498e341d0ccd7620c80588f97f73d: the Windows relinker CTest has completed successfully. All relinker, register-context, write-watch, ASan, conventions, labels, eligibility and report checks passed. Linux and Windows AGC jobs remain skipped by the PR workflow policy. The focused guest_wide_formatting test has still not been rerun after the rebase.

[MarcZX10]

I compared the previously tested head 06bd246798 with the current PR head f36936b1edbcd1b660a998dfe08680faea458de1: FormattingWide.cpp and GuestWideFormatting.cpp are byte-for-byte unchanged. The only difference among those paths is the debt documentation. So the focused test result from 06bd246798 still covers the current implementation and test source; I did not rerun the executable after the rebase.