Use the same JDK for building bazel and for its runtime.
Effectively, the former `toolchain_hostjdk8` java toolchain has been deprecated
and should no longer be used (in newer bazel)[1]:
```
default_java_toolchain(
name = "toolchain_hostjdk8",
...
)
```
[1]: 4fc4868065/tools/jdk/BUILD.tools (L384-L387)
* use default stdenv (clang 7)
* add no-arc.patch to make the xcode_locate tool compile without libarc-lite
* remove the `-mmacosx-version-min=10.9` flag from the bootstrap compile script
- bump protobuf to 3.13.0
- use recent rules_proto
- use recent bazel-skylib
- remove use of native.bind
Hopefully this is backward-compatible with bazel_3 and below
Bazel 4 is going to be a long term support release.
Latest version in NixPkgs so far was 3.3.1
There's a need for more recent version
https://github.com/NixOS/nixpkgs/issues/97497
All versions from 3.5.0 to 3.7.1 had some reproducibility issues
as noted in issue above, but there also seems to be
a working PR for 3.7.1 now at
https://github.com/NixOS/nixpkgs/pull/105439
Notable changes from bazel_3 setup:
- put python to default bash path
For autodetecting python toolchain
with strict action_env on and without this change
bazel would fail to autodetect host python.
There are some repos that define hermetic python
toolchains, but they aren't easy to use yet. Also
telling python paths to bazel isn't a 1-liner it
seems:
- action_env=PATH would affect cache
- declaring toolchain via BUILD&WORKSPACE files
is not per-user but more like per-repo and
affects cache too
Using python from nixpkgs shouldn't be too bad
in the lack of simpler hermetic python toolchain
options
- bazel_4.updater is bazel on `bazel query` to support
new constructs in WORKSPACE (load of vars, transitive
load etc). This is more robust but requires bazel
to run the updater, using bazel_3 for now. This is
only needed to bump package version, doesn't introduce
bazel_4 build dependency on bazel_3
https://blog.bazel.build/2020/11/10/bazel-4.0-announce.htmlhttps://blog.bazel.build/2020/11/10/long-term-support-release.htmlhttps://github.com/bazelbuild/bazel/issues/12455https://github.com/bazelbuild/bazel/releases/tag/4.0.0https://blog.bazel.build/2021/01/19/bazel-4-0.html
