Hash function changed in swift

[bkolb]

In a recent change, swift changed the way a hash is calculated. https://github.com/swiftlang/llvm-project/pull/9140/files#diff-dcdee0465a74e090b01bd5bd0d214f65f430f25a56b837ab627966318de1ff27R289

This change replicates this change.

Issue: #120

[bkolb]

I used this tag to build swift: swift-DEVELOPMENT-SNAPSHOT-2025-01-10-a and tested with this. it seems to work.

[keith]

thanks for submitting this! do we have to worry about backwards compat here?

can you rebase and fix the DCO?

[luispadron]

To make this backwards compatible, should index-import have a flag/arg to determine which hash algorithm to use?

[keith]

I think defaulting to this new behavior, and adding a flag for the legacy behavior, is probably fine

[luispadron]

@keith makes sense, i can add that if @bkolb cant get to it. Did we confirm this fixes issues though? I tested with a local build based off this branch using the release instructions but i was still seeing issues in Xcode 16.3:

/private/var/tmp/_bazel_lpadron/9ae9416857eb79bb978de35a53d54970/rules_xcodeproj.noindex/build_output_base/execroot/_main/bazel-out/_global_index_store/v5/units/UnsafeMutableBufferPointer+SE-0370.swift.o-1AIWS878QEG6M -- Failed opening
 '/private/var/tmp/_bazel_lpadron/9ae9416857eb79bb978de35a53d54970/rules_xcodeproj.noindex/build_output_base/execroot/_main/bazel-out/_global_index_store/v5/units/UnsafeMutableBufferPointer+SE-0370.swift.o-1AIWS878QEG6M': No such file or directory

More info in: MobileNativeFoundation/rules_xcodeproj#3160

[keith]

i haven't tested e2e, what has is it producing instead for this object?

[luispadron]

edited -- this was a mistake on my part i had not tested it e2e, forgot rules_swift also needs this patch

[luispadron]

Tested (correctly this time) end-to-end and this is working now in Xcode 16.3 & macOS 15.4 👍🏼

[luispadron]

@keith I have some commits to fix-up (once im done testing) but i added a flag over in: #131 and the hash change. We can close this in favor of that PR