Suppose I have a Gemfile like this:
source "https://rubygems.org"
gem "actioncable"
gem "websocket-driver", group: :test
The gemset.nix generated by Bundix 2.4.1 will set ActionCable's groups
to [ "default" ], and websocket-driver's to [ "test" ]. This means that
the generated bundlerEnv wouldn't include websocket-driver unless the
test group was included, even though it's required by the default group.
This is arguably a bug in Bundix (websocket-driver's groups should
probably be [ "default" "test" ] or just [ "default" ]), but there's no
reason bundlerEnv should omit dependencies even given such an input --
it won't necessarily come from Bundix, and it would be good for
bundlerEnv to do the right thing.
To fix this, filterGemset is now a recursive function, that adds
dependencies of gems in the group to the filtered gemset until it
stabilises on the gems that match the required groups, and all of their
recursive dependencies.
###### Motivation for this change
fixes#51825
###### Things done
<!-- Please check what applies. Note that these are not hard requirements but merely serve as information for reviewers. -->
- [x] Tested using sandboxing ([nix.useSandbox](http://nixos.org/nixos/manual/options.html#opt-nix.useSandbox) on NixOS, or option `sandbox` in [`nix.conf`](http://nixos.org/nix/manual/#sec-conf-file) on non-NixOS)
- Built on platform(s)
- [x] NixOS
- [ ] macOS
- [ ] other Linux distributions
- [ ] Tested via one or more NixOS test(s) if existing and applicable for the change (look inside [nixos/tests](https://github.com/NixOS/nixpkgs/blob/master/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
- [x] Fits [CONTRIBUTING.md](https://github.com/NixOS/nixpkgs/blob/master/.github/CONTRIBUTING.md).
---
Change introduced in #50672.
The patch does not apply on older protobuf like protobuf3_1
```
$ nix-build -E 'with import ./. { }; python3Packages.protobuf.override { protobuf = protobuf3_1; }'
unpacking sources
unpacking source archive /nix/store/1zdyl0cxaa8ha2v1zp75zzdjd6j99d0m-source
source root is source
setting SOURCE_DATE_EPOCH to timestamp 315619200 of file source/util/python/BUILD
patching sources
applying patch /nix/store/yagx7hvylnnjq7lxbcia0y5lq1r736w3-0a59054c30e4f0ba10f10acfc1d7f3814c63e1a7.patch
patching file google/protobuf/pyext/descriptor.cc
Hunk #1 succeeded at 55 (offset -1 lines).
patching file google/protobuf/pyext/descriptor_containers.cc
patching file google/protobuf/pyext/descriptor_pool.cc
Hunk #1 succeeded at 47 (offset -1 lines).
patching file google/protobuf/pyext/extension_dict.cc
Hunk #1 FAILED at 53.
1 out of 1 hunk FAILED -- saving rejects to file google/protobuf/pyext/extension_dict.cc.rej
patching file google/protobuf/pyext/message.cc
Hunk #1 succeeded at 82 (offset 3 lines).
Hunk #2 succeeded at 1425 (offset -104 lines).
```
Since the patch isn't necessary on python versions older than 3.7, let's
only apply it for version 3.7. This means that most things using older
protobuf implementation will now be able to build when using an older
pythonPackage set (as is most probably the case anyway).
This still leaves protobuf 3.1 using packages hanging, but the errors
will be localized to those that would be breaking anyway with the
upgrade to 3.7 as default python.
