bazel-watcher: 0.5.0 -> 0.9.0

[uri-canva]

Motivation for this change

Upgrade bazel-watcher so that it can be built with newer versions of Bazel.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[uri-canva]

cc @kalbasit

[kalbasit]

I'm on vacation until the 26th with limited internet and no laptop. The code looks great, but I'd love to make sure it runs before approving. /cc @Mic92 if he's available to review.

[Mic92]

@GrahamcOfBorg build bazel-watcher

[Mic92]

I got locally:

 fixed-output derivation produced path '/nix/store/c2hzc13ajagwfdfl4qiafvl5fq046j0q-bazel-watcher-0.9.0-deps' with sha256 hash '03knj3jmn5nn36kf3m4s30b4ms7hhmd1k9rcdzy70s8q6v2y84yr' instead of the expected hash '11pimgaxfx0p003zdxjx9fc9whgxh7qmycihakki4hm2n9ys22fq'

[kalbasit]

I got

fixed-output derivation produced path '/nix/store/jcnzfn13w02jn3lbf08pzq68jjz5grv7-bazel-watcher-0.9.0-deps' with sha256 hash '0239h6z605npjv8kpw3h3jkc0zlvbpvrr4xm30dvr9n5s9piqlnq' instead of the expected hash '11pimgaxfx0p003zdxjx9fc9whgxh7qmycihakki4hm2n9ys22fq'

I think the buildBazelPackage needs to be adjusted again. I uploaded /nix/store/jcnzfn13w02jn3lbf08pzq68jjz5grv7-bazel-watcher-0.9.0-deps here, can you compare the files with your version and adjust buildBazelPackage to remove those differences? See 86a5535 for my latest attempt at removing those differences.

[uri-canva]

Sorry was on vacation too. Will take a look.

[uri-canva]

Seems like the binaries include the output path in them, and strip -S doesn't strip it, so it's not a debug symbol. There some information in https://blog.filippo.io/reproducing-go-binaries-byte-by-byte/ about reproducible go binaries, it might be related to the build id.

$ go run gosym.go fetch_repo
/tmp/nix-build-bazel-watcher-0.9.0-deps.drv-0/output/external/bazel_gazelle_go_repository_tools/src/github.com/bazelbuild/bazel-gazelle/cmd/fetch_repo/fetch_repo.go
$ go run gosym.go ~/Downloads/nix/store/jcnzfn13w02jn3lbf08pzq68jjz5grv7-bazel-watcher-0.9.0-deps/bazel_gazelle_go_repository_tools/bin/fetch_repo
/build/output/external/bazel_gazelle_go_repository_tools/src/github.com/bazelbuild/bazel-gazelle/cmd/fetch_repo/fetch_repo.go

[Mic92]

why is this a fixed-input derivation anyway?

[uri-canva]

The whole derivation isn't fixed output, but the dependencies Bazel will download are. Unfortunately some of the dependencies it downloads also end up building native code.

[uri-canva]

You just gave me an idea though.

[uri-canva]

Done, change it to delete the gazelle binary tools since they can be rebuilt during the build, because it doesn't require accessing the network.

[kalbasit]

cool, let me give it another try! Thank you @uri-canva for working on this!