GIMME_ARCH arm64 does not set GOARCH to arm64

[csandanov]

...
env:
  matrix:
    - GIMME_OS=linux GIMME_ARCH=arm
    - GIMME_OS=linux GIMME_ARCH=arm64
...

GIMME_ARCH=arm works fine and sets GOARCH=arm unlike arm64. I don't know, maybe it's just not supported? Could not find a list of supported GIMME_ARCHs.

[philpennock]

The GIMME_ARCH is mostly just passed through to GOARCH or HOSTGOARCH as appropriate. There's some normalization to clean things up and handle some aliases, so that a few more values are valid, but otherwise if GOARCH supports a given value then so does GIMME_ARCH.

For arm64, there's an additional sanity-check to enforce a minimum Go version (1.5) and to pick a cross-compiler if the host architecture is not arm64.

What's the evidence that GOARCH was not set?

[csandanov]

So I've created a simple repo to demonstrate the issue, built it on travis-ci.com and, to my surprise, both arm and arm64 jobs show empty $GOARCH.

So I got back to my original (open sourced as well) repo with the issue which is built via travis-ci.org and it really shows empty $GOARCH on arm64 and expected $GOARCH=arm on arm.

Also, I've noticed that gimme arm environment takes a few minute to start unlike arm64, both on .ci and .org.

[tianon]

Your linked YAML has a typo:

echo $GOARH

(Should be GOARCH instead.)

[csandanov]

🤦‍♂️I'm sorry, fixed the typo, now .org version also shows that $GOARCH is missing for arm64 but present for arm: https://travis-ci.com/csandanov/gimme/builds/78049895

[philpennock]

That shows that for GIMME_ARCH=amd64, gimme errored out.

This line:

GIMME_OUTPUT="$(gimme 1.10.x | tee -a $HOME/.bashrc)" && eval "$GIMME_OUTPUT"

The | tee is suppressing the error. If this is guaranteed to be bash, then there needs to be a set -o pipefail for this construct to work. As it stands, it's buggy, because the && collapses to ; in this scenarios (unless tee can't write to ~/.bashrc). That's a Travis issue. No idea if setting pipefail will break a lot of user-scripts, but perhaps Travis could set it for the duration that it needs it, or just simplify the construction by breaking it into a couple of command-lines instead of trying to be clever. @tianon ?

Back to Gimme, rather than Travis's setup:
https://travis-ci.com/csandanov/gimme/jobs/132721199#L422-L424

The I don't have any idea what to do with '1.10.3'. is gimme failing to do stuff and bombing out.

When I grab a Linux box and run GIMME_DEBUG=3 GIMME_OS=linux GIMME_ARCH=arm64 gimme 1.10.3 I get an error caused by the cross-compilation binary being missing:

go tool dist: cannot invoke C compiler map["":"aarch64-linux-gnu-gcc" "linux/amd64":"gcc"]: exec: "aarch64-linux-gnu-gcc": executable file not found in $PATH

Now I've never used with cross-compilation with Gimme, so this is my first time, but AFAICT the required packages for Ubuntu are gcc-arm-linux-gnueabi binutils-arm-linux-gnueabi and after installing those, the cross-compiler is arm-linux-gnueabi-gcc whereas in this scenario gimme is defaulting the cross-compiler to aarch64-linux-gnu-gcc.

When I set GIMME_CC_FOR_TARGET=arm-linux-gnueabi-gcc I get a build. I'm not happy with the isolation offered by these directory names, but I have an existing PR which lays the groundwork for some cleanup here, so I'm not going to work on this until that's merged.

% GIMME_CC_FOR_TARGET=arm-linux-gnueabi-gcc gimme 1.10.3

unset GOOS;
export GOARCH="arm64";
export GOROOT='/home/pdp/.gimme/versions/go1.10.3.src';
export PATH="/home/pdp/.gimme/versions/go1.10.3.src/bin:${PATH}";
go version >&2;

export GIMME_ENV='/home/pdp/.gimme/envs/go1.10.3.src.env';

@csandanov please add that GIMME_CC_FOR_TARGET=arm-linux-gnueabi-gcc to the arm64 matrix line and confirm if this solves things for you?

Any cross-compilation experts who can say how we should be defaulting this?

I think we probably need to:

1. switch the cross-compile names so that we're safe against multi-arch NFS mounting of homedirs
2. figure out what is needed for cross-compilation; do we even need the above any more, or does modern Go handle cross-compilation to arm64 without needing to coerce gcc?
3. if we determine that we do need/want an external cross-compiler, we should test if it's installed early, to avoid a lot of work
4. cache download tarballs

[csandanov]

@philpennock it did not help https://travis-ci.com/csandanov/gimme/jobs/132879875#L457

[philpennock]

@csandanov Looks like Travis might be missing the cross-compilation tools needed.

I'm bowing out. (I don't work for Travis, I just contribute to gimme).