(for upgrading users, please see the notes at the bottom)
Bazel brought a lot of nice things to the table, such as rebuilds based on
content changes instead of modification times, caching of build products,
detection of incorrect build rules via a sandbox, and so on. Rewriting the build
in Bazel was also an opportunity to improve on the Makefile-based build we had
prior, which was pretty poor: most dependencies were external or not pinned, and
the build graph was poorly defined and mostly serialized. It was not uncommon
for fresh checkouts to fail due to floating dependencies, or for things to break
when trying to switch to an older commit.
For day-to-day development, I think Bazel served us reasonably well - we could
generally switch between branches while being confident that builds would be
correct and reasonably fast, and not require full rebuilds (except on Windows,
where the lack of a sandbox and the TS rules would cause build breakages when TS
files were renamed/removed).
Bazel achieves that reliability by defining rules for each programming language
that define how source files should be turned into outputs. For the rules to
work with Bazel's sandboxing approach, they often have to reimplement or
partially bypass the standard tools that each programming language provides. The
Rust rules call Rust's compiler directly for example, instead of using Cargo,
and the Python rules extract each PyPi package into a separate folder that gets
added to sys.path.
These separate language rules allow proper declaration of inputs and outputs,
and offer some advantages such as caching of build products and fine-grained
dependency installation. But they also bring some downsides:
- The rules don't always support use-cases/platforms that the standard language
tools do, meaning they need to be patched to be used. I've had to contribute a
number of patches to the Rust, Python and JS rules to unblock various issues.
- The dependencies we use with each language sometimes make assumptions that do
not hold in Bazel, meaning they either need to be pinned or patched, or the
language rules need to be adjusted to accommodate them.
I was hopeful that after the initial setup work, things would be relatively
smooth-sailing. Unfortunately, that has not proved to be the case. Things
frequently broke when dependencies or the language rules were updated, and I
began to get frustrated at the amount of Anki development time I was instead
spending on build system upkeep. It's now about 2 years since switching to
Bazel, and I think it's time to cut losses, and switch to something else that's
a better fit.
The new build system is based on a small build tool called Ninja, and some
custom Rust code in build/. This means that to build Anki, Bazel is no longer
required, but Ninja and Rust need to be installed on your system. Python and
Node toolchains are automatically downloaded like in Bazel.
This new build system should result in faster builds in some cases:
- Because we're using cargo to build now, Rust builds are able to take advantage
of pipelining and incremental debug builds, which we didn't have with Bazel.
It's also easier to override the default linker on Linux/macOS, which can
further improve speeds.
- External Rust crates are now built with opt=1, which improves performance
of debug builds.
- Esbuild is now used to transpile TypeScript, instead of invoking the TypeScript
compiler. This results in faster builds, by deferring typechecking to test/check
time, and by allowing more work to happen in parallel.
As an example of the differences, when testing with the mold linker on Linux,
adding a new message to tags.proto (which triggers a recompile of the bulk of
the Rust and TypeScript code) results in a compile that goes from about 22s on
Bazel to about 7s in the new system. With the standard linker, it's about 9s.
Some other changes of note:
- Our Rust workspace now uses cargo-hakari to ensure all packages agree on
available features, preventing unnecessary rebuilds.
- pylib/anki is now a PEP420 implicit namespace, avoiding the need to merge
source files and generated files into a single folder for running. By telling
VSCode about the extra search path, code completion now works with generated
files without needing to symlink them into the source folder.
- qt/aqt can't use PEP420 as it's difficult to get rid of aqt/__init__.py.
Instead, the generated files are now placed in a separate _aqt package that's
added to the path.
- ts/lib is now exposed as @tslib, so the source code and generated code can be
provided under the same namespace without a merging step.
- MyPy and PyLint are now invoked once for the entire codebase.
- dprint will be used to format TypeScript/json files in the future instead of
the slower prettier (currently turned off to avoid causing conflicts). It can
automatically defer to prettier when formatting Svelte files.
- svelte-check is now used for typechecking our Svelte code, which revealed a
few typing issues that went undetected with the old system.
- The Jest unit tests now work on Windows as well.
If you're upgrading from Bazel, updated usage instructions are in docs/development.md and docs/build.md. A summary of the changes:
- please remove node_modules and .bazel
- install rustup (https://rustup.rs/)
- install rsync if not already installed (on windows, use pacman - see docs/windows.md)
- install Ninja (unzip from https://github.com/ninja-build/ninja/releases/tag/v1.11.1 and
place on your path, or from your distro/homebrew if it's 1.10+)
- update .vscode/settings.json from .vscode.dist
The enum changes should work on PyQt 5.x, and are required in PyQt 6.x.
They are not supported by the PyQt5 typings however, so we need to run
our tests with PyQt6.
Now behaves the same way as standard find&replace:
- Will match substrings
- Regexs can be used to match multiple items; we no longer split
input on spaces.
- The find&replace dialog has been updated to add tags to the field
list.
- Introduced a new transact() method that wraps the return value
in a separate struct that describes the changes that were made.
- Changes are now gathered from the undo log, so we don't need to
guess at what was changed - eg if update_note() is called with identical
note contents, no changes are returned. Card changes will only be set
if cards were actually generated by the update_note() call, and tag
will only be set if a new tag was added.
- mw.perform_op() has been updated to expect the op to return the changes,
or a structure with the changes in it, and it will use them to fire the
change hook, instead of fetching the changes from undo_status(), so there
is no risk of race conditions.
- the various calls to mw.perform_op() have been split into separate
files like card_ops.py. Aside from making the code cleaner, this works
around a rather annoying issue with mypy. Because we run it with
no_strict_optional, mypy is happy to accept an operation that returns None,
despite the type signature saying it requires changes to be returned.
Turning no_strict_optional on for the whole codebase is not practical
at the moment, but we can enable it for individual files.
Still todo:
- The cursor keeps moving back to the start of a field when typing -
we need to ignore the refresh hook when we are the initiator.
- The busy cursor icon should probably be delayed a few hundreds ms.
- Still need to think about a nicer way of handling saveNow()
- op_made_changes(), op_affects_study_queue() might be better embedded
as properties in the object instead
Running and testing should be working on the three platforms, but
there's still a fair bit that needs to be done:
- Wheel building + testing in a venv still needs to be implemented.
- Python requirements still need to be compiled with piptool and pinned;
need to compile on all platforms then merge
- Cargo deps in cargo/ and rslib/ need to be cleaned up, and ideally
unified into one place
- Currently using rustls to work around openssl compilation issues
on Linux, but this will break corporate proxies with custom SSL
authorities; need to conditionally use openssl or use
https://github.com/seanmonstar/reqwest/pull/1058
- Makefiles and docs still need cleaning up
- It may make sense to reparent ts/* to the top level, as we don't
nest the other modules under a specific language.
- rspy and pylib must always be updated in lock-step, so merging
rspy into pylib as a private module would simplify things.
- Merging desktop-ftl and mobile-ftl into the core ftl would make
managing and updating translations easier.
- Obsolete scripts need removing.
- And probably more.
* `Any` used for pickle methods, this could probably be improved
with some kind of Callable
* str used for self.base, though this may be a problem for
different OSes. Some type of os.PathLike might be good.
* Line 75, type ignored: mypy was complaining about no. of args,
and kwargs there didn't seem to be needed. Separate issue to test,
though.
- field changes are now applied when user closes dialog with save
button, in bulk
- models diag now fetches note type and saves it as required, instead
of holding on top a copy that can grow stale as changes are made in
subdialogs
- both dialogs now perform operations in the backend
- note.model() now fetches the note type on the fly, instead of
holding on to a copy that may become stale
