Combine `OldDiagnostic` and `Diagnostic` (#19053)
## Summary
This PR is a collaboration with @AlexWaygood from our pairing session
last Friday.
The main goal here is removing `ruff_linter::message::OldDiagnostic` in
favor of
using `ruff_db::diagnostic::Diagnostic` directly. This involved a few
major steps:
- Transferring the fields
- Transferring the methods and trait implementations, where possible
- Converting some constructor methods to free functions
- Moving the `SecondaryCode` struct
- Updating the method names
I'm hoping that some of the methods, especially those in the
`expect_ruff_*`
family, won't be necessary long-term, but I avoided trying to replace
them
entirely for now to keep the already-large diff a bit smaller.
### Related refactors
Alex and I noticed a few refactoring opportunities while looking at the
code,
specifically the very similar implementations for
`create_parse_diagnostic`,
`create_unsupported_syntax_diagnostic`, and
`create_semantic_syntax_diagnostic`.
We combined these into a single generic function, which I then copied
into
`ruff_linter::message` with some small changes and a TODO to combine
them in the
future.
I also deleted the `DisplayParseErrorType` and `TruncateAtNewline` types
for
reporting parse errors. These were added in #4124, I believe to work
around the
error messages from LALRPOP. Removing these didn't affect any tests, so
I think
they were unnecessary now that we fully control the error messages from
the
parser.
On a more minor note, I factored out some calls to the
`OldDiagnostic::filename`
(now `Diagnostic::expect_ruff_filename`) function to avoid repeatedly
allocating
`String`s in some places.
### Snapshot changes
The `show_statistics_syntax_errors` integration test changed because the
`OldDiagnostic::name` method used `syntax-error` instead of
`invalid-syntax`
like in ty. I think this (`--statistics`) is one of the only places we
actually
use this name for syntax errors, so I hope this is okay. An alternative
is to
use `syntax-error` in ty too.
The other snapshot changes are from removing this code, as discussed on
[Discord](https://discord.com/channels/1039017663004942429/1228460843033821285/1388252408848847069):
https://github.com/astral-sh/ruff/blob/34052a1185392963c465737e9647f404abdfe8d5/crates/ruff_linter/src/message/mod.rs#L128-L135
I think both of these are technically breaking changes, but they only
affect
syntax errors and are very narrow in scope, while also pretty
substantially
simplifying the refactor, so I hope they're okay to include in a patch
release.
## Test plan
Existing tests, with the adjustments mentioned above
---------
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
