cargo fails to download git repo on powerpc

[hpckurt]

Trying to build rattler-build on powerpc: https://github.com/prefix-dev/rattler-build

If it was working correctly, cargo update would automatically download and update the local git dependencies. However, instead it results in the following error:

$ RUST_BACKTRACE=1 cargo update
    Updating git repository `https://github.com/wolfv/zip2`
error: failed to load source for dependency `zip`

Caused by:
  Unable to update https://github.com/wolfv/zip2?branch=patched

Caused by:
  object not found - no match for id (8fcb25229346479487823cbe0f9326d74c666d13); class=Odb (9); code=NotFound (-3)

You can git clone the repository with that specific commit ID perfectly fine outside of cargo.

Meta

rustc --version --verbose:

rustc 1.83.0 (90b35a623 2024-11-26)
binary: rustc
commit-hash: 90b35a6239c3d8bdabc530a6a0816f7ff89a0aaf
commit-date: 2024-11-26
host: powerpc-unknown-linux-gnu
release: 1.83.0
LLVM version: 19.1.1

Backtrace from cargo build:

RUST_BACKTRACE=1 cargo build
    Updating git repository `https://github.com/wolfv/zip2`
remote: Enumerating objects: 55146, done.
remote: Counting objects: 100% (3043/3043), done.
remote: Compressing objects: 100% (169/169), done.
remote: Total 55146 (delta 2971), reused 2874 (delta 2874), pack-reused 52103 (from 2)
Receiving objects: 100% (55146/55146), 50.42 MiB | 6.99 MiB/s, done.
Resolving deltas: 100% (8637/8637), done.
From https://github.com/wolfv/zip2
 * [new ref]           8fcb25229346479487823cbe0f9326d74c666d13 -> refs/commit/8fcb25229346479487823cbe0f9326d74c666d13
error: failed to load source for dependency `zip`

Caused by:
  Unable to update https://github.com/wolfv/zip2?branch=patched#8fcb2522

Caused by:
  revspec '8fcb25229346479487823cbe0f9326d74c666d13' not found; class=Reference (4); code=NotFound (-3)

[epage]

I wasn't able to reproduce it on My x64 Linux system.

Can you try running CARGO_NET_GIT_FETCH_WITH_CLI=true cargo update? Unsure at what step the failure is happening if that will affect it but my hope is this can give us insight into what might be happening.

[hpckurt]

Same exact error:

CARGO_NET_GIT_FETCH_WITH_CLI=true cargo update
    Updating git repository `https://github.com/wolfv/zip2`
error: failed to load source for dependency `zip`

Caused by:
  Unable to update https://github.com/wolfv/zip2?branch=patched

Caused by:
  object not found - no match for id (8fcb25229346479487823cbe0f9326d74c666d13); class=Odb (9); code=NotFound (-3)

I can also verify that the issue doesn't occur on x64 or arm64 (linux). Could it be a 32bit platform issue?

[ehuss]

Can you say how I can set up an emulated environment for powerpc-unknown-linux-gnu? Is there an image I can somehow run?

[hpckurt]

@ehuss You can always create a powerpc chroot using qemu-user-static and debootstrap

[ehuss]

Sorry, I don't know what those words mean. Can you give me the exact commands to run in a typical Ubuntu environment to give me a shell inside a powerpc environment?

[hpckurt]

Sorry, I don't know what those words mean. Can you give me the exact commands to run in a typical Ubuntu environment to give me a shell inside a powerpc environment?

Here are instructions to get a qemu rootfs chroot working (Assuming you're already root)

1. apt update
2. apt install qemu-user-static binfmt-support debootstrap debian-ports-archive-keyring 
3. gpg --keyserver keyring.debian.org --recv-keys 8D69674688B6CB36
4. mkdir debianpowerpc
5. debootstrap --arch=powerpc --keyring=/etc/apt/trusted.gpg.d/debian-ports-archive-2024.gpg  --foreign sid debianpowerpc/ http://ftp.ports.debian.org/debian-ports
6. cd debianpowerpc/
7. mount -o bind /dev dev/
8. mount -t devpts pts dev/pts/
9. mount -t sysfs sys sys/
10. mount -t proc proc proc/
11. cd ..
12. chroot debianpowerpc/
13. Install rust using rustup in chroot

[ehuss]

Thanks for the detailed steps! I'm able to reproduce with that.

I suspect this is the same as #8719 (comment). It's having trouble accessing the filesystem correctly.

What's interesting is that building cargo inside the root doesn't reproduce the problem. I wonder if there is something different about the crosstools-ng environment that leads to the C code using different definitions, or if there's some glibc shenanigans going on.

[hpckurt]

Thanks for the detailed steps! I'm able to reproduce with that.

I suspect this is the same as #8719 (comment). It's having trouble accessing the filesystem correctly.

What's interesting is that building cargo inside the root doesn't reproduce the problem. I wonder if there is something different about the crosstools-ng environment that leads to the C code using different definitions, or if there's some glibc shenanigans going on.

So is the "fix" to just recompile rust?

[hpckurt]

New error after trying to recompile rust:

warning: spurious network error (3 tries remaining): could not read directory '/home/wiiu/.cargo/git/db/pubgrub-4eebf9758cb3b340/refs': Value too large for defined data type; class=Os (2)
warning: spurious network error (2 tries remaining): could not read directory '/home/wiiu/.cargo/git/db/pubgrub-4eebf9758cb3b340/refs': Value too large for defined data type; class=Os (2)
warning: spurious network error (1 tries remaining): could not read directory '/home/wiiu/.cargo/git/db/pubgrub-4eebf9758cb3b340/refs': Value too large for defined data type; class=Os (2)
error: failed to load source for dependency `version-ranges`

Caused by:
  Unable to update https://github.com/astral-sh/pubgrub?rev=57832d0588fbb7aab824813481104761dc1c7740#57832d05

Any fix recommendations?

[hpckurt]

@ehuss I just confirmed that the issue isn't present if you install rust directly from the debian repos. It's able to download git repos without issue.

It seems to only happen with the rustup version.