Add triplet variables to control abi entries for binarycache

[Osyotr]

VCPKG_IGNORED_ABI_KEYS: list of entries to remove from from vcpkg_abi_info.txt (key1;key2;...;keyN)
VCPKG_ADDITIONAL_ABI_ENTRIES: list of additional entries to add to vcpkg_abi_info.txt (key1 value1;key2 value2;...;keyN valueN)

It's now possible to completely override triplet hash or remove dependencies hashes from abi entries.
⚠Of course, this must be used with caution. ⚠

set(VCPKG_TARGET_ARCHITECTURE x64)
set(VCPKG_CRT_LINKAGE dynamic)
set(VCPKG_LIBRARY_LINKAGE dynamic)

# ⚠ This might break things, but we take the risk
set(VCPKG_ADDITIONAL_ABI_ENTRIES "my_custom_triplet_abi 9C6553BC-E762-458E-BDEF-2FEEBD6388BD")
set(VCPKG_IGNORED_ABI_KEYS "triplet_abi" "powershell")

if("${PORT}" STREQUAL "libpng")
    list(APPEND VCPKG_IGNORED_ABI_KEYS "zlib")
endif()

[bansan85]

This feature is really nice. Tracking powershell version is annoying because Windows Update breaks the whole cache. And adding new entries may be needed (i.e. to track version of external tools).

Will it be merged ?

There is conflicts for the merge action. Files changed are small. I don't have write permission in this MR. If @Osyotr don't have time to fix it, is it fine that I create another MR that can be merged ?

[Osyotr]

Tracking powershell version is annoying because Windows Update breaks the whole cache.

Use --x-abi-tools-use-exact-versions.

And adding new entries may be needed (i.e. to track version of external tools).

This is now possible using VCPKG_HASH_ADDITIONAL_FILES albeit a bit clumsy.

Will it be merged ?

I don't have high hopes for that, considering there hasn't been any comments from maintainers in three years.
Feel free to resubmit, but you will also need to write tests.

[bansan85]

I noticed VCPKG_HASH_ADDITIONAL_FILES, but I was afraid it would require keeping the file alive in the build tree (or somewhere else).
I just made a test, and it's fine. vcpkg adds in vcpkg_abi_info.txt:

additional_file_0 33307da56af13f791584518fef2e49641180bfbf2ef7b2d256c9ab6fad564f80

and the cache worked as expected.

I will also try --x-abi-tools-use-exact-versions the next time PowerShell will be updated.

Thanks.

[BillyONeal]

I think this needs:

1. A better description of what you want to do with this. This may be a much more 'general' hammer than we need here.
2. At least 1 end to end test for each newly added knob.
3. Docs, probably that need to include (1) as well as counterexamples.

VCPKG_IGNORED_ABI_KEYS I am weakly against at this time as anything it could be used to exclude is likely to break vcpkg contracts with customers, but I could be convinced given a sufficient value for (1) above.

VCPKG_ADDITIONAL_ABI_ENTRIES I am weakly against at this time because I do not understand how it differs from just having the content in the triplet file itself. I become weakly in favor if we also do #596 or #800 as that will give it an obvious use case.

[Osyotr]

A better description of what you want to do with this

Every touch to the triplet file is a guaranteed world rebuild and I wanted to have control over that by replacing triplet_abi with own abi entry that is updated manually. Cheap alternative to #596 and #800.

Also, at that time I did some patching of Qt library so I wanted to speed up testing of the patches by skipping rebuilds of some heavy-ish dependencies like QtWebKit. The workflow was like this:

• Add qt5-base to VCPKG_IGNORED_ABI_KEYS for qt5-webkit.
• Patch qt5-base.
• Modify triplet:
  • If I know that qt5-base abi has changed (e.g. changed some public header):
    • Add or bump version of qt5-base_ABI in VCPKG_ADDITIONAL_ABI_ENTRIES.
  • If I didn't change anything meaningful:
    • Do nothing.
• Test changes with my app.

---

Nowadays I just don't need touch the triplet very often (this trick together with VCPKG_HASH_ADDITIONAL_FILES helps).
And for quick patching I sometimes use leftovers from vcpkg build and just copy binaries manually.

I will close this PR (at least for now).

[BillyONeal]

Also, at that time I did some patching of Qt library so I wanted to speed up testing of the patches by skipping rebuilds of some heavy-ish dependencies like QtWebKit. The workflow was like this:

• Add qt5-base to VCPKG_IGNORED_ABI_KEYS for qt5-webkit.

• Patch qt5-base.

• Modify triplet:

  • If I know that qt5-base abi has changed (e.g. changed some public header):

    • Add or bump version of qt5-base_ABI in VCPKG_ADDITIONAL_ABI_ENTRIES.

  • If I didn't change anything meaningful:

    • Do nothing.

• Test changes with my app.

That is a very good (1) and flips my vote from weakly against to weakly in favor.