This prevents an issue when trying to check in changes top
bazel-generated template files,
which aren't actually valid C++, making clangd_tidy issue errors and
block the commit.
This provides a native harness with several advantages over
`pre-commit`:
- Faster when initializing the cache
- Smaller cache sizes: under 43mb compared to over 62mb
- Better integration with `uv` for Python usage
Steps for migrating for existing contributors:
1. Install `prek` following instructions in the updated docs.
2. Replace hooks in an existing checkout with a special flag:
```sh
prek install --overwrite
```
The `--overwrite` flag is what removes the old hooks.
If you used the pre-push variant:
```sh
prek install --hook-type pre-push --overwrite
```
3. Optional cleanups:
```sh
rm -rf ~/.cache/pre-commit # reclaim the old hook-environment cache
pipx uninstall pre-commit # if installed via pipx; or `brew uninstall
pre-commit`
```
Assisted-by: Antigravity with Gemini
The `--dump-cpp-ast` file tests strip references to Clang builtins so
that the expected output is target-independent. The filter anchored a
`__`-prefixed builtin identifier on a preceding space or quote, which
matches the x86-64 `__va_list_tag` spelling but not the AArch64
`std::__va_list`, where `__` is preceded by the `::` namespace
qualifier. That left a single `RecordType 'std::__va_list'` line
unfiltered on AArch64, producing a spurious autoupdate diff for
`thunk_ast.carbon`.
Anchor the match on a preceding `:` as well so namespace-qualified
builtins are also filtered.
Carbon's test workflow covered Linux on x86-64 and macOS on AArch64, but
had no Linux AArch64 coverage, so AArch64-specific issues that don't
reproduce on macOS could land unnoticed. Add an `ubuntu-22.04-arm`
runner to the matrix.
The release used for Linux does not publish the monolithic
`LLVM-*-Linux-ARM64` package, only a `clang+llvm-*-aarch64-linux-gnu`
community build with a smaller tool set, so the Ubuntu setup now selects
the tarball by `runner.arch`. The prune step uses `rm -f` since the two
packages do not ship an identical set of tools to remove.
Assisted-by: Claude Code with Claude Opus 4.7
This removes the need to install any specific version of Python or
figure out how to configure it by instead asking users to install `uv`
and letting it manage Python. Among other advantages, `uv` is designed
to be fast enough to embed directly into our scripts.
We were already using this in `bench_runner.py` so that the script could
import non standard library dependencies. Moving to it for the rest of
our Python unifies the approach and will also enable dependencies
whenever needed.
I've left `github_tools` alone as it has special handling with its own
Bazel setup.
I've updated the contributing tools to explain the approach here.
The labeling script will now directly set a check status for the PR as
`pending` when it marks something as dependent, and clear it when it no
longer is. This emulates a check that starts when marked as dependent
and runs until the last dependency lands, allowing automerge and other
workflows to work cleanly.
The branch protection rule will have to be updated to the new spelling.
This should do the same key thing as #7113, but integrated to the new
script.
Assisted-by: Antigravity with Gemini
This should detect when a PR has a dependency of another open PR and add
a comment and label describing it. The comment will even do a
best-effort to compute the best starting commit for review.
Whenever PRs are closed, it will also scan the open depnedent PRs and
try to either remove the PRs in the comment or if it reaches zero the
label.
It works to update a single comment on a PR rather than adding more
comments.
Assisted-by: Antigravity with Gemini
The target was renamed in `82fad290285baf9763132a13b1f73de1e7919074`
from `//toolchain/install:carbon_toolchain_tar_gz_rule` to
`//toolchain/install:carbon_toolchain_tar_gz`
This has been working really well for me, is incredibly faster than the
other approach, and some commits continue to hit bugs in the old system
where files that aren't even going to be run through `clangd-tidy` end
up tripping up the execution. Hopefully all of that is resolved with the
new version.
Note that this will require changing the branch protections to use new
names for all of the checks and be somewhat disruptive. There aren't any
really good ways I could find of fixing this. Some options that I
explored:
- Have a single `pre-merge` workflow file that contains all of the other
workflows, splitting as much of the logic as we can into re-usable
files. This would basically merge testing, `pre-commit`, and
`clangd-tidy` checking into a single workflow file. However, it would
also delay the pre-commit suggestions action to only run once _all_ of
these finish, rather than as soon as pre-commit finishes.
- Serialize `pre-commit` and the rest of `pre-merge` to get the effect
of the above option but without the downside. Instead, the downside
would be serializing some of our actions.
- Have a single `pre-merge` workflow that triggers whenever any of the
other workflows completes, and have it check whether all the others have
completed. It will fail until it reaches that point. This requires
passing in GitHub keys to the workflow so that it can check the status
of other checks, and documentation online seems to indicate it is
sometimes flaky, I assume because of racing triggers of events or
check-status not being guaranteed consistent in the queries.
- Have a single `pre-merge` workflow that polls, waiting for all the
other workflows to finish using some Python logic. This requires
building and maintaining code to poll GitHub, keys to authorize that
polling, and handling all of the failure modes of a polling operation --
timeouts, network issues, etc.
Maybe there are others, but not sure what they look like. Suggestions
welcome here.
I'm hesitant to either delay the pre-commit suggestions or serialize
pre-commit execution. And the complexity or flakiness of the other two
options seem worse than having to re-work the branch protections each
time the naming here changes. But interested if folks think a different
direction would be better.
Assisted-by: Antigravity with Gemini
This also switches to a more Bazel-based install layout, skipping the
FHS-based synthetic layout. The FHS-based layout is still reconstructed
explicitly when building an installable tar-ball.
The biggest change is to configure the just-built install as a Bazel
toolchain, including allowing it to build its own runtime libraries as
native Bazel libraries. This removes the need for a monolithic runtimes
build, all of that code logic is removed.
This should also pave the way to using the just-built toolchain for
doing a full 3-stage bootstrap. Building the 2nd stage is included here
as it was a particularly effective way to test that the Bazel
integration was fully working. Adding a 3rd-stage check for stability is
future work, but should be pretty easy.
There is a down-side: this uses the busybox to do the runtimes
compilation, which means they will be re-built after ~any change to
Carbon. However, the integration with Bazel should largely pay for this,
and we can continue to factor the tests away from depending on built
runtimes in most cases.
Now that we're building and testing the runtimes more directly, this
surfaced a problem with the layout of runtimes on macOS that is fixed
here. All of the Darwin OSes use a custom layout for their resource
directory compared to other targets. We now model this in both the C++
built runtimes and the Bazel built runtimes.
Assisted-by: Gemini via Antigravity
Missed in #6848 (had it sitting in my workspace uncommitted, apparently
have gotten too used to jj; using git here)
Assisted-by: Google Antigravity with Gemini
In addition to the general updates, this switches to a required python
3.10 for pre-commit (3.9 is losing support from black).
Note endpoints for build actions are expanding significantly: see
https://app.stepsecurity.io/github/carbon-language/carbon-lang/actions/runs/22779388360?tab=recommendations&jobId=66080970460
for example, I think just the sources are being increased as a
side-effect of updates (and possibly also things not performing as well
as they should have before).
Similarly allowing sudo in pre-commit because it was actually causing
errors in part of build setup, which used sudo to remove files.
Assisted-by: Google Antigravity with Gemini
Previously, we left it on by default and only disabled it in CI.
However, as we have grown more and more examples, the cost of stamping
has steadily risen: every example has to be rebuilt because the busybox
binary and installation contain an updated stamp.
I noticed that I was almost never getting cache hits for these even when
I should and it seems like what was once true is no more for daily
development.
I've updated the default, the docs for the default, and explicitly
enabled stamping in the nightly release workflow. I left the explicit
disabling in the CI workflows as that seems harmless and a good defense
in case we want to shift the default again.
One alternative that I didn't pursue because of the complexity was to
create two distinct installation prefixes automatically, one with the
`.nostamp` suffixed binaries installed and one without that suffix. We
could then point example builds and other within-Bazel uses at the
non-stamped tree to get maximal caching. But it would create two whole
installation trees without much benefit. It seemed simpler to just
disable stamping by default for development builds.
Generally seems to be working as intended: clang-tidy has variance from
a few minutes to an hour; clang-tidy hovers around 10 minutes. In this
case, the long tail of slow execution is more visible, partly because
tests will often take close to 10 minutes, if not more.
Branch enforcement should already be switched.
Currently it's called `assign_reviewers` as it was copied from the
workflow that does said task. But this workflow is setting labels, so
call it `set_labels`.
The Ubuntu 24 builders have a newer GLIBC than is present on the
compiler-explorer machines:
https://github.com/compiler-explorer/compiler-explorer/issues/7636#issuecomment-2880962252.
This results in the following error when running Carbon nightly:
```
/opt/compiler-explorer/carbon-trunk/bin/carbon: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.38' not found (required by /opt/compiler-explorer/carbon-trunk/bin/carbon)
```
To resolve this, we need to build Carbon in a sysroot with a compatible
glibc version, and the most straightforward way to do that is to bump
our builders back down to Ubuntu 22.
To do that, we can't use apt.llvm.org again, since Ubuntu 22 is no
longer supported there. So we revert back to pulling a Linux X64 tarball
from the LLVM GitHub Releases page. Instead of getting an
ubuntu-specific tarball (which does not exist), we grab the generic
Linux one, which seems to work fine.
Note that the binaries in the LLVM release package appear to depend on
glibc version 2.34, as determined by `objdump -T bin/clang|grep GLIBC_|
sed 's/.*GLIBC_\([.0-9]*\).*/\1/g' | sort -Vu`, so these binaries should
hopefully be okay to package with the Carbon toolchain for the
compiler-explorer machines as well.
The version of clangd/clang-tidy on developer machines has slowly
diverged from the one on the CI builders, which is causing a slowly
increasing amount of pain as clang-tidy CI runs fail (incorrectly) over
things that a newer clangd/clang-tidy was perfectly fine with locally.
This bumps the Clang version used in the ubuntu builders to 19, which is
the most recent in Debian stable.
We use https://apt.llvm.org instead of LLVM's GitHub releases
(https://github.com/llvm/llvm-project/releases) as the former more
reliably has packages for newer Clang/LLVM versions on x64. The
community-build releases binaries on LLVM's GitHub have stopped
including Ubuntu packages that match the GitHub x64 Ubuntu workers for
some time (for at least the 18 and 19 releases).
By moving to apt.llvm.org packages we only download and install the
headers and libraries needed for development, rather than every output
of building llvm, which is much faster and saves lots of disk space. We
also remove the system installations of other versions of clang/llvm so
we should end up using negative disk space. We can no longer easily
cache the installation but apt.llvm.org is a reliable end point.
We bump the ubuntu image version for the github workers to 24.04, as
apt.llvm.org has stopped building images for 22.10 in 2022 at its end of
life.
The `pre_commit` workflow disabled sudo unlike the other workflows that
install Clang/LLVM, including the `clang-tidy` workflow (which is also
run on `pull_request`). We bring it into alignment with the other
workflows so that we can install the llvm packages. And we lock its
ubuntu image to 24.04 so that it can be moved in lockstep with the other
workflows that depend on Clang/LLVM.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Trying to improve resilience against failures such as:
```
INFO: Repository rules_jvm_external+ instantiated at:
<builtin>: in <toplevel>
Repository rule http_archive defined at:
/home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_tools/tools/build_defs/repo/http.bzl:392:31: in <toplevel>
ERROR: /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_tools/tools/build_defs/repo/http.bzl:137:45: An error occurred during the fetch of repository 'rules_jvm_external+':
Traceback (most recent call last):
File "/home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_tools/tools/build_defs/repo/http.bzl", line 137, column 45, in _http_archive_impl
download_info = ctx.download_and_extract(
```
https://github.com/carbon-language/carbon-lang/actions/runs/14719625211/job/41311145495?pr=5379
It looks like GitHub currently has a high rate of these, which it
shouldn't, but also maybe we can do a little more to weather these
service issues.
To show flag behavior:
```
╚╡./scripts/run_bazel.py --attempts=5 --retry-all-errors :foo
Command ':foo' not found. Try 'bazel help'.
Retrying exit code 2 because it may be transient...
Command ':foo' not found. Try 'bazel help'.
Retrying exit code 2 because it may be transient...
Command ':foo' not found. Try 'bazel help'.
Retrying exit code 2 because it may be transient...
Command ':foo' not found. Try 'bazel help'.
Retrying exit code 2 because it may be transient...
Command ':foo' not found. Try 'bazel help'.
╚╡./scripts/run_bazel.py --attempts=5 --retry-all-errors query //... | wc -l
INFO: Invocation ID: ffdf9480-0245-442d-885f-ee91a3d86b68
Loading: 0 packages loaded
367
╚╡./scripts/run_bazel.py --attempts=5 :foo
Command ':foo' not found. Try 'bazel help'.
```
On the last run, [test (ubuntu-22.04,
opt)](https://github.com/carbon-language/carbon-lang/actions/runs/14737410033/job/41366888473?pr=5386)
has an example of this working:
```
INFO: Invocation ID: 3f276297-6dc5-4007-a333-dcadd4db55f4
no actions running
no actions running
no actions running
no actions running
no actions running
no actions running
no actions running
no actions running
no actions running
WARNING: Download from https://github.com/bazelbuild/bazel-skylib/releases/download/1.7.1/bazel-skylib-1.7.1.tar.gz failed: class java.io.IOException GET returned 618 jwt:jwt-not-provided
INFO: Repository bazel_skylib+ instantiated at:
<builtin>: in <toplevel>
Repository rule http_archive defined at:
/home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_tools/tools/build_defs/repo/http.bzl:392:31: in <toplevel>
ERROR: /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_tools/tools/build_defs/repo/http.bzl:137:45: An error occurred during the fetch of repository 'bazel_skylib+':
Traceback (most recent call last):
File "/home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_tools/tools/build_defs/repo/http.bzl", line 137, column 45, in _http_archive_impl
download_info = ctx.download_and_extract(
Error in download_and_extract: java.io.IOException: Error downloading [https://github.com/bazelbuild/bazel-skylib/releases/download/1.7.1/bazel-skylib-1.7.1.tar.gz] to /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_skylib+/temp62784[869](https://github.com/carbon-language/carbon-lang/actions/runs/14737410033/job/41366888473?pr=5386#step:5:887)09382546624/bazel-skylib-1.7.1.tar.gz: GET returned 618 jwt:jwt-not-provided
no actions running
no actions running
ERROR: Error loading '@@rules_python+//python/extensions:python.bzl' for module extensions, requested by /home/runner/work/carbon-lang/carbon-lang/MODULE.bazel:147:23: at /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/rules_python+/python/extensions/python.bzl:48:6: at /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/rules_python+/python/private/python.bzl:17:6: at /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_features+/features.bzl:3:6: Encountered error while reading extension file 'globals.bzl': no such package '@@bazel_features++version_extension+bazel_features_globals//': no such package '@@bazel_skylib+//lib': java.io.IOException: Error downloading [https://github.com/bazelbuild/bazel-skylib/releases/download/1.7.1/bazel-skylib-1.7.1.tar.gz] to /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_skylib+/temp6278486909382546624/bazel-skylib-1.7.1.tar.gz: GET re
ERROR: Error loading '@@rules_cc+//cc:extensions.bzl' for module extensions, requested by https://bcr.bazel.build/modules/rules_cc/0.1.1/MODULE.bazel:12:29: at /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/rules_cc+/cc/extensions.bzl:16:6: at /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_features+/features.bzl:3:6: Encountered error while reading extension file 'globals.bzl': no such package '@@bazel_features++version_extension+bazel_features_globals//': no such package '@@bazel_skylib+//lib': java.io.IOException: Error downloading [https://github.com/bazelbuild/bazel-skylib/releases/download/1.7.1/bazel-skylib-1.7.1.tar.gz] to /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_skylib+/temp6278486909382546624/bazel-skylib-1.7.1.tar.gz: GET returned 618 jwt:jwt-not-provided: at /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/rules_cc+/cc/extensions.bzl:16:6: at /h
ERROR: Error loading '@@rules_python+//python/extensions:python.bzl' for module extensions, requested by /home/runner/work/carbon-lang/carbon-lang/MODULE.bazel:147:23: at /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/rules_python+/python/extensions/python.bzl:48:6: at /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/rules_python+/python/private/python.bzl:17:6: at /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_features+/features.bzl:3:6: Encountered error while reading extension file 'globals.bzl': no such package '@@bazel_features++version_extension+bazel_features_globals//': no such package '@@bazel_skylib+//lib': java.io.IOException: Error downloading [https://github.com/bazelbuild/bazel-skylib/releases/download/1.7.1/bazel-skylib-1.7.1.tar.gz] to /home/runner/.cache/bazel/_bazel_runner/8f839eaeb716f9d034eabdfa7ebecdb0/external/bazel_skylib+/temp6278486909382546624/bazel-skylib-1.7.1.tar.gz: GET re
INFO: Invocation ID: e2062912-715f-47ec-a0bc-9d1b4fee9e5d
no actions running
no actions running
no actions running
no actions running
no actions running
no actions running
<root> (carbon@_)
Retrying a failure because it may be transient...
INFO: Invocation ID: 7d4ee250-882f-480d-9c8d-2d92e67462fc
Loading: 0 packages loaded
367
```
I'm doing this separately from removing the explorer/ and installers/
directories so that it's easier to review the side-effects.
Note for the main README, I didn't think it was worth keeping a mention
of "used to have a prototype interpreter, now archived" versus focusing
on the existing toolchain (for "Currently, we have fleshed out").
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
This is trying to reduce how much we run tidy over due to poor
performance of tidy.
It's opening the door for issues where a header file is modified in a
way that introduces tidy issues in a different target. However, that's
not the typical tidy issue we see.
There may also be a risk where a source file indirectly becomes a source
file for a target in a way that `same_pkg_direct_rdeps` doesn't return,
but I'm not sure that's applicable for how we use targets.
An example of this locating a diagnostic error can be found in the "Add
tidy issue" commit's run (which I cancelled before it finished running,
but note the error):
https://github.com/carbon-language/carbon-lang/actions/runs/13932649182/job/38993348130?pr=5144
We were discussing this, `long term` only applies to issues and not PRs
(per past discussion, we don't really expect PRs should be inactive for
months). Renaming to `long term issue` to be more specific and hopefully
reduce confusion.
Without this, the merge queue blocks on results but they never get
triggered and show up. This will need to merge before we re-enable
`clang-tidy` enforcement on the trunk branch.
Trying to improve robustness against failures such as
[here](https://github.com/carbon-language/carbon-lang/actions/runs/11845529962/job/33011203628):
```
WARNING: Download from https://ftp.gnu.org/gnu/m4/m4-1.4.18.tar.xz failed: class java.net.ConnectException Connection refused
```
Which is coming from the target-determinator invocation:
```
subprocess.CalledProcessError: Command '['/home/runner/.cache/carbon-lang-scripts/target-determinator', '--bazel=/usr/local/bin/bazelisk', 'a720921dfb99c21f08832663c91a1f9e48a1bcc4']' returned non-zero exit status 1.
```
My thought is that the `bazel cquery` should trigger equivalent
downloads (equally though, I'd thought the `bazel mod deps` would do
that, so I don't want to give the impression of confidence).
It's harder to inject this into the target-determinator command line,
since we'd need something that retries by default.
Came up due to [libc++ install
issues](https://discord.com/channels/655572317891461132/655577725347561492/1302023663155023905)
We've discussed clang version verification, and adding that as long as
I'm in here. The more significant bit is the libc++ check, which if it's
not installed should fail like:
```
(tons of output)
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/lib/llvm-16/lib/clang/16/include
/usr/local/include
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
/usr/local/google/home/jperkins/.cache/bazel/_bazel_jperkins/85deb7d9d96f7e0e80b42618a55969d7/external/_main~clang_toolchain_extension~bazel_cc_toolchain/_temp:6:2: error: "No libc++ install found!"
#error "No libc++ install found!"
^
1 error generated.
ERROR: Analysis of target '//toolchain:toolchain' failed; build aborted: Analysis failed
INFO: Elapsed time: 0.265s, Critical Path: 0.08s
INFO: 1 process: 1 internal.
ERROR: Build did NOT complete successfully
```
pre-commit runs bazel, and GitHub runners have an old clang by default
(caught by the new check), so I'm installing here for a consistent
version.
---------
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Dana Jansens
Lucile Rose Nihlen
Richard Smith
Chandler Carruth
Jon Ross-Perkins