I believe this reflects the intent, but the phrasing of "even if
`MyBaseClass` is not" implies that `MyBaseClass` _can_ be final in
`partial MyBaseClass`. Also, make clear it's allowed on `abstract`
classes, not only `base` (this seems explicitly intended from the
`MyAbstractClass` example around line 1482).
We propose updating our milestones to accelerate design and
implementation of
memory safety in Carbon, and a roadmap for 2025 reflecting this change.
We also
provide a retrospective for 2024's progress.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Also makes the style guide explicitly comment on void, but this was the
intent IIRC because it matches Carbon's `-> ()` (and "always" versus
"except for void", which we definitely went back and forth on).
Includes adjusting function pointers, which I definitely forget this
syntax works sometimes.
Excludes utils/tree_sitter/src/scanner.c because it claims to be C, but
really we should probably fix that to be cpp.
Introduce a principle that the Carbon language should not encroach on
the
developer's namespace. Satisfy this principle by making `Core` a
keyword.
---------
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
The WORKSPACE file is deprecated; support is already off by default, and
it'll be removed in the next major bazel release. Our main dependency is
tree-sitter, and I'm trying to address that here.
We're currently using https://github.com/elliottt/rules_tree_sitter, but
that hasn't been updated in a couple years, meaning it lacks
MODULE.bazel support. In the registry, there's
https://registry.bazel.build/modules/tree-sitter-bazel, but this is only
the *parser* libraries of tree-sitter, not the *generator*. I'm using it
for that much, at least.
For the *generator*, which transforms grammar.js to parser.c/h, I'm just
requiring a non-hermetic invocation (i.e., people who want to work on it
will need to install tree-sitter; see the README.md updates). I tried
running it manually, but parser.c is about 600 KB; pre-commit rejects
files that large and I don't think an exception makes sense to override
for this (it'd probably also grow substantially if the grammar were
updated to cover more syntax). In order to make the non-hermetic call
not break "bazel build //..." for most developers, I'm marking most
targets in the package as manual.
Note, I did look long and hard at using `aspect_rules_js`/`rules_nodejs`
to invoke npm. This took a lot of time, and I have a commit that's
mostly working, except I hit a point where it uses `declare_symlink`
which we disallow for compatibility reasons (commit "Lots of work for
figuring out rule_js uses declare_symlink" on the PR). As a consequence,
I think we can't use the primary supported ways to have hermetic npm
calls.
Also, `treesitter` -> `tree_sitter` because it's generally called
`tree-sitter`, two words. We even had a `treesitter/src/tree_sitter`
directory so it's a bit inconsistent.
As far as bugs here, the parser library breaks bazel queries, e.g. the
error:
```
ERROR: Evaluation of query "somepath(//..., @llvm-project//third-party/unittest:gtest)" failed: preloading transitive closure failed: no such package '@@[unknown repo 'platforms' requested from @@tree-sitter-bazel+]//': The repository '@@[unknown repo 'platforms' requested from @@tree-sitter-bazel+]' could not be resolved: No repository visible as '@platforms' from repository '@@tree-sitter-bazel+'
```
I'm just excluding tree_sitter from queries where I can to work around
the error.
This updates to bazel 8.0.0, also updating bazel mod deps and tools to
make that function. The release is a couple weeks old, and we haven't
updated in a while, and it's a major release. Note it includes some
incompatible flag flips that this is trying to update with respect to.
I'll try generally enabling incompatible support separately.
The most visible bazel behavior change here will be the change from `~`
to `+` in repo path names. (If you're curious,
https://github.com/bazelbuild/bazel/issues/23127 indicates this fixes a
Windows performance issue)
Note that this is building on top of both the action env update in #4728
(which got me started down this path) and the proto removal in #4731
(which would add significant work to this update). Only the commit
starting at "Work towards bazel 8.0.0" is specifically part of this PR.
This restores the symlinks for the installation, but teaches the busybox
info search to look for a relative path to the busybox binary itself
before walking through symlinks. This let's it find the tree structure
when directly invoking `prefix_root/bin/carbon` or similar, either
inside of a Bazel rule or from the command line, and mirrors how we
expect the installed tree to look. This works even when Bazel resolves
the symlink target fully, and potentially to something nonsensical like
a CAS file.
In order to make a convenient Bazel target that can be used with `bazel
run //toolchain`, this adds an override to explicitly set the desired
argv[0] to use when selecting a mode for the busybox and a busybox
binary. Currently, the workaround uses an environment variable because
that required the least amount of plumbing, and seems a useful override
mechanism generally, but I'm open to other approaches.
This should allow a few things to work a bit more nicely:
- It should handle sibling symlinks like `clang++` to `clang` or
`ld.lld` to `lld`, where that symlink in turn points at the busybox.
We want to use *initial* `argv[0]` value to select the mode there.
- It avoids bouncing through Python (or other subprocesses) when
invoking the `carbon` binary in Bazel rules, which will be nice for
building the example code and benchmarking.
It does come at a cost of removing one feature: the initial symlink
can't be some unrelated alias like `my_carbon_symlink` -- we expect the
*first* argv[0] name to have the meaningful filename for selecting
a busybox mode.
It also trades the complexity of the Python script for some complexity
in the busybox search in order to look for a relative `carbon-busybox`
binary. On the whole, I think that tradeoff is worthwhile, but it isn't
free.
---------
Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Pursuant to discussion regarding #4699, turn on
`misc-non-private-member-variables-in-classes` using the
`IgnoreClassesWithAllMemberVariablesBeingPublic` flag (the check treats
structs as classes, so we need this for structs with all-public
members). Updates the style guide notes to match, which should be pretty
minor due to the scoping of test fixtures.
Also fixes some underscore uses in test files on the way. Basically this
is keeping the style for [class data member
naming](https://google.github.io/styleguide/cppguide.html#Variable_Names)
even while making them public.
Proposes a set of core features for declaring and implementing generic
variadic
functions.
A "pack expansion" is a syntactic unit beginning with `...`, which is a
kind of
compile-time loop over sequences called "packs". Packs are initialized
and
referred to using "pack bindings", which are marked with the `each`
keyword at
the point of declaration and the point of use.
The syntax and behavior of a pack expansion depends on its context, and
in some
cases by a keyword following the `...`:
- In a tuple literal expression (such as a function call argument list),
`...`
iteratively evaluates its operand expression, and treats the values as
successive elements of the tuple.
- `...and` and `...or` iteratively evaluate a boolean expression,
combining
the values using `and` and `or`, and ending the loop early if the
underlying
operator short-circuits.
- In a statement context, `...` iteratively executes a statement.
- In a tuple literal pattern (such as a function parameter list), `...`
iteratively matches the elements of the scrutinee tuple. In conjunction
with
pack bindings, this enables functions to take an arbitrary number of
arguments.
---------
Co-authored-by: josh11b <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Co-authored-by: Carbon Infra Bot <carbon-external-infra@google.com>
The only documentation I can find for `.bazelversion` is in
https://github.com/bazelbuild/bazelisk/blob/master/README.md. However,
`bazel` will error out if it doesn't match the `.bazelversion`. For
example:
```
╚╡/usr/bin/bazel build :all
ERROR: The project you're trying to build requires Bazel 7.3.0 (specified in [elided]/carbon-lang/.bazelversion), but it wasn't found in /usr/bin.
```
Switching to this because the `MODULE.bazel` requires tighter version
pinning in order to avoid churn, and this should help catch mistakes
early.
In `MODULE.bazel`, demote mention of the version issue because it should
only really occur now when the version is being deliberately changed, so
the connection should be more apparent.
This adds language to explain where the types of constraints can or can
not appear (attached-to an impl-as vs in-a type expression). And
describes the impact of using a rewrite vs same-type constraint inside
the body of the affected code, and thus why a rewrite is preferable when
the constraint is of a single facet type.
The prettier pre-commit mirror is no longer supported
(https://github.com/pre-commit/mirrors-prettier). This switches to a
direct call, and updates to 3.3.3. And I'm now specifying types for it
to apply to, rather than letting it ignore unknown files; overall just
trying to separate out which linter sees what.
To comment on formatting changes:
- In most cases, seems to be getting confused by `[]` use in markdown
when it's not part of a link. This looks like a regression, but not one
we're broadly affected by.
- p0107.md - caught an issue with a malformed broken bad link which I've
tried to fix.
- p3720.md - looks like a fix.
Note, prettier has a 4.0.0 alpha release. As best as I could tell, that
only affected the .prettierrc.yaml processing. I changed the glob there
for forwards compatibility.
The name ComparableFromDifferenceFn comes from the next example. In this
example ComparableFromDifference is the name of the class that will be
implictly cast to a Facet matching Comparable.
As described in symlink_helpers.bzl, copied here for visibility:
Symlinking busybox things needs special logic.
This is because Bazel doesn't cache the actual symlink, resulting in
essentially resolved symlinks being produced in place of the expected
tool. As a consequence, we can't rely on the symlink name when dealing
with busybox entries.
An example repro of this using a local build cache is:
bazel build //toolchain
bazel clean
bazel build //toolchain
We could in theory get reasonable behavior with
`ctx.actions.declare_symlink`, but that's disallowed in our `.bazelrc`
for cross-environment compatibility.
The particular approach here uses the Python script as a launching pad
so that the busybox still receives an appropriate location in argv[0],
allowing it to find other files in the lib directory. Arguments are
inserted to get equivalent behavior as if symlink resolution had
occurred.
The underlying bug is noted at:
https://github.com/bazelbuild/bazel/issues/23620
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>
This should substantially reduce the total build size of `-c dbg`
builds, and especially improve cache hits during incremental
development. I'm seeing over 50% reduction total on Linux in just the
raw size of a complete debug build. Even on macOS where we can't use
split DWARF there are substantial reductions.
Note that LLDB and GDB want slightly different flags to have the best
experience with split debug information, and so the build and
documentation have been updated to enable LLDB's flags by default but
provide clear instructions for switching to GDB's flags, and they are
structured so that this can be done persistently for an individual
developer.
Establish a process for getting commit access. We will:
- Grant access based on a developer's commit history.
- Someone with commit access should nominate, and a contributor may ask.
- A lead will approve nominations. Only one lead is needed.
- Remove commit access once someone is idle for 6 months.
- "Idle" means no significant project activity on any of GitHub,
Discord,
or in meetings.
- Access removed due to being idle will be restored on request.
---------
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
I'm trying to use this just to document the de facto state. This is
linked to #4246, but I'm trying to keep the two arranged to allow
independent merges.
Trying to pull in key elements of #3762, #3763, and #3980 (decl matching
and `extern`, essentially). These aren't specific to any particular
declaration type, but are common to entities, so suggesting a new doc
oriented on that.
There's probably more that could be said here, I'm just focused on
getting the recent formal discussion mirrored into the design.
---------
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
Demo site: https://jonmeow.carbon-lang.dev/
I'm trying to keep work under the `/website` subdirectory so that the
misc files don't interfere with unrelated views of the repository. The
`prebuild.py` script does some work to move things around and add
frontmatter, helping the jekyll generation.
I'm using the "just-the-docs" theme because I think it's a decent match
for what we want, and getting jekyll up and running with it wasn't too
difficult. Note #1526 proposed using Docusaurus; I started out there,
but was having trouble getting it working with newer versions. The
plugins in particular I got stuck trying to make work, which sent me
looking for options that we could have working with less customization.
I do lean towards jekyll though, because it's what GH uses so hopefully
we can get a more consistent experience.
Having a website has been approved for a while under #1492, but hasn't
been a priority. I'm mainly doing this because I want to just be able to
point people to carbon-lang.dev and have easy links that way.
---------
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Update the operator precedence to achieve a few goals:
- Form operators into groups which behave similarly
- Make the group of operators ("top-level operators") that capture
everything to the right, like `if`...`then`...`else`, behave similarly
to the left, so that rearranging expressions won't change how they
group.
- Add the `where` operator, used to specify constraints on facet types,
to the precedence chart, to define how it interacts with other
operators.
- Make the operator precedence diagram prettier, so that it eventually
can be made into a poster that Carbon programmers can hang on their
walls.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Also a small pass on workflow names.
Note, I'm a little concerned that the test/nightly release/pre-commit
endpoints may be fragile. At the same time, it's also where it may be
most useful, to prevent network access by arbitrary test code. I think
this is imperfect, but maybe we can try it out and see if it's much of
an issue.
Note, the discord wiki action is currently broken, this should fix it.
I was considering making a "/bazel" alias for this, but I'm really on
the fence about whether that's a good choice. However, I do think this
is good to have to simplify installs.
Fixes#3071 and #3896
Proposal for how Carbon version numbers work:
- A single version across language, standard library, compiler, linker,
etc.
- Semantic Versioning (SemVer) based
- Details of how SemVer criteria for major, minor, and patch should
apply to
Carbon
- Details of how we will operate before 1.0 and how this connects to
Carbon's
milestones
- Directional guidance for future work including post-1.0 versions, LTS
versions, and standardization
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Also makes an alias so that this is easier to find. Verified that
running the alias still finds prelude files.
Note the actual target is printed when building (although a symlink is
also created, using that symlink confuses file-finding).
```
╚╡bazel build :carbon
...
Target //toolchain/install:prefix_root/bin/carbon up-to-date:
bazel-bin/toolchain/install/prefix_root/bin/carbon
```
The current approach was done to work-around a limitation that we can
only have a single link per box, but is unscalable. Instead have a
single link to a new sections of the document that describes the box,
and has multiple links.
---------
Co-authored-by: Josh L <josh11b@users.noreply.github.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Following discussions around #3958, try to provide more specific
semantics. Note we currently don't follow this everywhere, particularly
in AddInst calls, but the intent is to shift. Per discussion, designated
initializers are preferred when possible. And the
`google-readability-casting` diagnostics are poor, but with this may
primarily flag cases which should be using a different constructor
syntax, so are just a rocky way to get there.
---------
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Replace image file in /docs/images/ directory and update the svg editing
document to reflect the change to package syntax from proposal #3927Closes#3969
Jon Ross-Perkins
Dana Jansens
Geoff Romerandjosh11b
Chandler CarruthandRichard Smith
Céline Dedaj
David Blaikie
Brymer Meneses
Rajat Roy