System package mode does not work with legacy package hashes

[BratishkaErik]

Zig Version

0.14.0-dev.3460+6d29ef0ba

Steps to Reproduce and Observed Behavior

Hello, after #22994 was merged, system package retrieval no longer works with dependencies which were not updated to the new format.

For example you can checkout zigtools/zls@336f468 and run following commands:

$ zig build
# works fine
$ zig build --fetch --global-cache-dir deps/
$ zig build --system deps/p/                
/home/bratishkaerik/github.com/zls/build.zig.zon:21:14: error: package not found at 'deps/p//1220102cb2c669d82184fb1dc5380193d37d68b54e8d75b76b2d155b9af7d7e2e76d'
            .hash = "1220102cb2c669d82184fb1dc5380193d37d68b54e8d75b76b2d155b9af7d7e2e76d",
             ^~~~
$ exa --tree -L1 deps/p/
deps/p
├── known_folders-0.0.0-Fy-PJtLDAADGDOwYwMkVydMSTp_aN-nfjCZw6qPQ2ECL
├── lsp_codegen-0.1.0-CMjjo0ZXCQB-rAhPYrlfzzpU0u0u2MeGvUucZ-_g32eg
└── N-V-__8AABhrAQAQLLLGadghhPsdxTgBk9N9aLVOjXW3ay0V

Note that it does not error when you re-fetch this dependency to get hash saved in new format:

         .diffz = .{
             .url = "https://github.com/ziglibs/diffz/archive/ef45c00d655e5e40faf35afbbde81a1fa5ed7ffb.tar.gz",
-            .hash = "1220102cb2c669d82184fb1dc5380193d37d68b54e8d75b76b2d155b9af7d7e2e76d",
+            .hash = "N-V-__8AABhrAQAQLLLGadghhPsdxTgBk9N9aLVOjXW3ay0V",
         },

Expected Behavior

To work like it does for regular builds. If they are still allowed for regular builds, I would expect them to work with system mode too.

... or be banned in both scenarios. With current model, to fix system mode you would need to convert every hash of every dependency (direct or transient) anyway.

[alexrp]

#23051?

[BratishkaErik]

#23051?

It says:

Suggested workaround: upgrade to new hash format
Alternate workaround: use zig-0.13.0 to zig fetch legacy packages

Second one would not work with zig build --fetch/--help (which is used for fetching in live/Git-HEAD packages for Gentoo).

First one requires me to patch all packages' build.zig.zon when they have legacy hashes, or ping upstream maintainers to do this (which kinda weakens point of compatibility IMHO).

[nektro]

the compatibility kept is only that if u already have the files downloaded then it would continue to work.

First one requires me to patch all packages' build.zig.zon when they have legacy hashes, or ping upstream maintainers to do this

this interpretation is also my understanding and unlikely to be changed since a system packaging environment is going to always be a cold cache

[andrewrk]

Please make an argument for reopening #23051