These snapshot changes should *all* only be a result of changes to
trailing whitespace in the output. I checked a psuedo random sample of
these, and the whitespace found in the previous snapshots seems to be an
artifact of the rendering and _not_ of the source data. So this seems
like a strict bug fix to me.
There are other snapshots with whitespace changes, but they also have
other changes that we split out into separate commits. Basically, we're
going to do approximately one commit per category of change.
This represents, by far, the biggest chunk of changes to snapshots as a
result of the `annotate-snippets` upgrade.
This is pretty much just moving to the new API and taking care to use
byte offsets. This is *almost* enough. The next commit will fix a bug
involving the handling of unprintable characters as a result of
switching to byte offsets.
When confronted with `raise from exc` the parser will now create a
`StmtRaise` that has `None` for the exception and `exc` for the cause.
Before, the parser created a `StmtRaise` with `from` for the exception,
no cause, and a spurious expression `exc` afterwards.
This PR adds a syntax error if the parser encounters a `TryStmt` that
has except clauses both with and without a star.
The displayed error points to each except clause that contradicts the
original except clause kind. So, for example,
```python
try:
....
except: #<-- we assume this is the desired except kind
....
except*: #<--- error will point here
....
except*: #<--- and here
....
```
Closes#14860
## Summary
This PR gets rid of the `requirements.in` and `requirements.txt` files
in the `scripts/fuzz-parser` directory, and replaces them with
`pyproject.toml` and `uv.lock` files. The script is renamed from
`fuzz-parser` to `py-fuzzer` (since it can now also be used to fuzz
red-knot as well as the parser, following
https://github.com/astral-sh/ruff/pull/14566), and moved from the
`scripts/` directory to the `python/` directory, since it's now a
(uv)-pip-installable project in its own right.
I've been resisting this for a while, because conceptually this script
just doesn't feel "complicated" enough to me for it to be a full-blown
package. However, I think it's time to do this. Making it a proper
package has several advantages:
- It means we can run it from the project root using `uv run` without
having to activate a virtual environment and ensure that all required
dependencies are installed into that environment
- Using a `pyproject.toml` file means that we can express that the
project requires Python 3.12+ to run properly; this wasn't possible
before
- I've been running mypy on the project locally when I've been working
on it or reviewing other people's PRs; now I can put the mypy config for
the project in the `pyproject.toml` file
## Test Plan
I manually tested that all the commands detailed in
`python/py-fuzzer/README.md` work for me locally.
---------
Co-authored-by: David Peter <sharkdp@users.noreply.github.com>
## Summary
This PR fixes a bug to raise a syntax error when an unparenthesized
generator expression is used as an argument to a call when there are
more than one argument.
For reference, the grammar is:
```
primary:
| ...
| primary genexp
| primary '(' [arguments] ')'
| ...
genexp:
| '(' ( assignment_expression | expression !':=') for_if_clauses ')'
```
The `genexp` requires the parenthesis as mentioned in the grammar. So,
the grammar for a call expression is either a name followed by a
generator expression or a name followed by a list of argument. In the
former case, the parenthesis are excluded because the generator
expression provides them while in the later case, the parenthesis are
explicitly provided for a list of arguments which means that the
generator expression requires it's own parenthesis.
This was discovered in https://github.com/astral-sh/ruff/issues/12420.
## Test Plan
Add test cases for valid and invalid syntax.
Make sure that the parser from CPython also raises this at the parsing
step:
```console
$ python3.13 -m ast parser/_.py
File "parser/_.py", line 1
total(1, 2, x for x in range(5), 6)
^^^^^^^^^^^^^^^^^^^
SyntaxError: Generator expression must be parenthesized
$ python3.13 -m ast parser/_.py
File "parser/_.py", line 1
sum(x for x in range(10), 10)
^^^^^^^^^^^^^^^^^^^^
SyntaxError: Generator expression must be parenthesized
```
## Summary
This PR updates the linter, specifically the token-based rules, to work
on the tokens that come after a syntax error.
For context, the token-based rules only diagnose the tokens up to the
first lexical error. This PR builds up an error resilience by
introducing a `TokenIterWithContext` which updates the `nesting` level
and tries to reflect it with what the lexer is seeing. This isn't 100%
accurate because if the parser recovered from an unclosed parenthesis in
the middle of the line, the context won't reduce the nesting level until
it sees the newline token at the end of the line.
resolves: #11915
## Test Plan
* Add test cases for a bunch of rules that are affected by this change.
* Run the fuzzer for a long time, making sure to fix any other bugs.
## Summary
This PR splits the re-lexing logic into two parts:
1. `TokenSource`: The token source will be responsible to find the
position the lexer needs to be moved to
2. `Lexer`: The lexer will be responsible to reduce the nesting level
and move itself to the new position if recovered from a parenthesized
context
This split makes it easy to find the new lexer position without needing
to implement the backwards lexing logic again which would need to handle
cases involving:
* Different kinds of newlines
* Line continuation character(s)
* Comments
* Whitespaces
### F-strings
This change did reveal one thing about re-lexing f-strings. Consider the
following example:
```py
f'{'
# ^
f'foo'
```
Here, the quote as highlighted by the caret (`^`) is the start of a
string inside an f-string expression. This is unterminated string which
means the token emitted is actually `Unknown`. The parser tries to
recover from it but there's no newline token in the vector so the new
logic doesn't recover from it. The previous logic does recover because
it's looking at the raw characters instead.
The parser would be at `FStringStart` (the one for the second line) when
it calls into the re-lexing logic to recover from an unterminated
f-string on the first line. So, moving backwards the first character
encountered is a newline character but the first token encountered is an
`Unknown` token.
This is improved with #12067fixes: #12046fixes: #12036
## Test Plan
Update the snapshot and validate the changes.
## Summary
This PR fixes the lexer logic to **not** consume the newline character
for an unterminated string literal.
Currently, the lexer would consume it to be part of the string itself
but that would be bad for recovery because then the lexer wouldn't emit
the newline token ever. This PR fixes that to avoid consuming the
newline character in that case.
This was discovered during https://github.com/astral-sh/ruff/pull/12060.
## Test Plan
Update the snapshots and validate them.
## Summary
This PR fixes a bug introduced in
https://github.com/astral-sh/ruff/pull/12008 which didn't consider the
two character newline after the line continuation character.
For example, consider the following code highlighted with whitespaces:
```py
call(foo # comment \\r\n
\r\n
def bar():\r\n
....pass\r\n
```
The lexer is at `def` when it's running the re-lexing logic and trying
to move back to a newline character. It encounters `\n` and it's being
escaped (incorrect) but `\r` is being escaped, so it moves the lexer to
`\n` character. This creates an overlap in token ranges which causes the
panic.
```
Name 0..4
Lpar 4..5
Name 5..8
Comment 9..20
NonLogicalNewline 20..22 <-- overlap between
Newline 21..22 <-- these two tokens
NonLogicalNewline 22..23
Def 23..26
...
```
fixes: #12028
## Test Plan
Add a test case with line continuation and windows style newline
character.
## Summary
(I'm pretty sure I added this in the parser re-write but must've got
lost in the rebase?)
This PR raises a syntax error if the type parameter list is empty.
As per the grammar, there should be at least one type parameter:
```
type_params:
| invalid_type_params
| '[' type_param_seq ']'
type_param_seq: ','.type_param+ [',']
```
Verified via the builtin `ast` module as well:
```console
$ python3.13 -m ast parser/_.py
Traceback (most recent call last):
[..]
File "parser/_.py", line 1
def foo[]():
^
SyntaxError: Type parameter list cannot be empty
```
## Test Plan
Add inline test cases and update the snapshots.
## Summary
This PR updates the parser test infrastructure to validate the token
ranges.
From the code documentation:
```
/// Verifies that:
/// * the ranges are strictly increasing when loop the tokens in insertion order
/// * all ranges are within the length of the source code
```
Follow-up from #12016 and #12017resolves: #11938
## Test Plan
Make sure that there are no failures.
## Summary
This PR updates the unterminated string error range to not include the
final newline character.
This is a follow-up to #12016 and required for #12019
This is not done for when the unterminated string goes till the end of
file (not a newline character). The unterminated f-string range is
correct.
### Why is this required for #12019 ?
Because otherwise the token ranges will overlap. For example:
```py
f"{"
f"{foo!r"
```
Here, the re-lexing logic recovers from an unterminated f-string and
thus emitting a `Newline` token for the one at the end of the first
line. But, currently the `Unknown` and the `Newline` token would overlap
because the `Unknown` token (unterminated string literal) range would
include the newline character.
## Test Plan
Update and validate the snapshot.
## Summary
This PR fixes the range highlighted for the line continuation error.
Previously, it would highlight an incorrect range:
```
1 | call(a, b, \\\
| ^^ Syntax Error: unexpected character after line continuation character
2 |
3 | def bar():
|
```
And now:
```
|
1 | call(a, b, \\\
| ^ Syntax Error: unexpected character after line continuation character
2 |
3 | def bar():
|
```
This is implemented by avoiding to update the token range for the
`Unknown` token which is emitted when there's a lexical error. Instead,
the `push_error` helper method will be responsible to update the range
to the error location.
This actually becomes a requirement which can be seen in follow-up PRs.
## Test Plan
Update and validate the snapshot.
## Summary
This PR fixes a bug where the re-lexing logic didn't consider the line
continuation character being present before the newline character. This
meant that the lexer was being moved back to the newline character which
is actually ignored via `\`.
Considering the following code:
```py
f'middle {'string':\
'format spec'}
```
The old token stream is:
```
...
Colon 18..19
FStringMiddle 19..29 (flags = F_STRING)
Newline 20..21
Indent 21..29
String 29..42
Rbrace 42..43
...
```
Notice how the ranges are overlapping between the `FStringMiddle` token
and the tokens emitted after moving the lexer backwards.
After this fix, the new token stream which is without moving the lexer
backwards in this scenario:
```
FStringStart 0..2 (flags = F_STRING)
FStringMiddle 2..9 (flags = F_STRING)
Lbrace 9..10
String 10..18
Colon 18..19
FStringMiddle 19..29 (flags = F_STRING)
FStringEnd 29..30 (flags = F_STRING)
Name 30..36
Name 37..41
Unknown 41..44
Newline 44..45
```
fixes: #12004
## Test Plan
Add test cases and update the snapshots.
## Summary
I look at the token stream a lot, not specifically in the playground but
in the terminal output and it's annoying to scroll a lot to find
specific location. Most of the information is also redundant.
The final format we end up with is: `<kind> <range> (flags = ...)` e.g.,
`String 0..4 (flags = BYTE_STRING)` where the flags part is only
populated if there are any flags set.
## Summary
This PR does some housekeeping into moving certain structs into related
modules. Specifically,
1. Move `LexicalError` from `lexer.rs` to `error.rs` which also contains
the `ParseError`
2. Move `Token`, `TokenFlags` and `TokenValue` from `lexer.rs` to
`token.rs`
## Summary
This PR removes the duplication around `is_trivia` functions.
There are two of them in the codebase:
1. In `pycodestyle`, it's for newline, indent, dedent, non-logical
newline and comment
2. In the parser, it's for non-logical newline and comment
The `TokenKind::is_trivia` method used (1) but that's not correct in
that context. So, this PR introduces a new `is_non_logical_token` helper
method for the `pycodestyle` crate and updates the
`TokenKind::is_trivia` implementation with (2).
This also means we can remove `Token::is_trivia` method and the
standalone `token_source::is_trivia` function and use the one on
`TokenKind`.
## Test Plan
`cargo insta test`
## Summary
This PR avoids moving back the lexer for a triple-quoted f-string during
the re-lexing phase.
The reason this is a problem is that for a triple-quoted f-string the
newlines are part of the f-string itself, specifically they'll be part
of the `FStringMiddle` token. So, if we moved the lexer back, there
would be a `Newline` token whose range would be in between an
`FStringMiddle` token. This creates a panic in downstream usage.
fixes: #11937
## Test Plan
Add test cases and validate the snapshots.
## Summary
This PR updates the linter to show all the parse errors as diagnostics
instead of just the first one.
Note that this doesn't affect the parse error displayed as error log
message. This will be removed in a follow-up PR.
### Breaking?
I don't think this is a breaking change even though this might give more
diagnostics. The main reason is that this shouldn't affect any users
because it'll only give additional diagnostics in the case of multiple
syntax errors.
## Test Plan
Add an integration test case which would raise more than one parse
error.
## Summary
This PR updates the re-lexing logic to avoid consuming the trailing
whitespace and move the lexer explicitly to the last newline character
encountered while moving backwards.
Consider the following code snippet as taken from the test case
highlighted with whitespace (`.`) and newline (`\n`) characters:
```py
# There are trailing whitespace before the newline character but those whitespaces are
# part of the comment token
f"""hello {x # comment....\n
# ^
y = 1\n
```
The parser is at `y` when it's trying to recover from an unclosed `{`,
so it calls into the re-lexing logic which tries to move the lexer back
to the end of the previous line. But, as it consumed all whitespaces it
moved the lexer to the location marked by `^` in the above code snippet.
But, those whitespaces are part of the comment token. This means that
the range for the two tokens were overlapping which introduced the
panic.
Note that this is only a bug when there's a comment with a trailing
whitespace otherwise it's fine to move the lexer to the whitespace
character. This is because the lexer would just skip the whitespace
otherwise. Nevertheless, this PR updates the logic to move it explicitly
to the newline character in all cases.
fixes: #11929
## Test Plan
Add test cases and update the snapshot. Make sure that it doesn't panic
on the code snippet in the linked issue.
## Summary
This PR is a follow-up on #11845 to add the re-lexing logic for normal
list parsing.
A normal list parsing is basically parsing elements without any
separator in between i.e., there can only be trivia tokens in between
the two elements. Currently, this is only being used for parsing
**assignment statement** and **f-string elements**. Assignment
statements cannot be in a parenthesized context, but f-string can have
curly braces so this PR is specifically for them.
I don't think this is an ideal recovery but the problem is that both
lexer and parser could add an error for f-strings. If the lexer adds an
error it'll emit an `Unknown` token instead while the parser adds the
error directly. I think we'd need to move all f-string errors to be
emitted by the parser instead. This way the parser can correctly inform
the lexer that it's out of an f-string and then the lexer can pop the
current f-string context out of the stack.
## Test Plan
Add test cases, update the snapshots, and run the fuzzer.
## Summary
This PR implements the re-lexing logic in the parser.
This logic is only applied when recovering from an error during list
parsing. The logic is as follows:
1. During list parsing, if an unexpected token is encountered and it
detects that an outer context can understand it and thus recover from
it, it invokes the re-lexing logic in the lexer
2. This logic first checks if the lexer is in a parenthesized context
and returns if it's not. Thus, the logic is a no-op if the lexer isn't
in a parenthesized context
3. It then reduces the nesting level by 1. It shouldn't reset it to 0
because otherwise the recovery from nested list parsing will be
incorrect
4. Then, it tries to find last newline character going backwards from
the current position of the lexer. This avoids any whitespaces but if it
encounters any character other than newline or whitespace, it aborts.
5. Now, if there's a newline character, then it needs to be re-lexed in
a logical context which means that the lexer needs to emit it as a
`Newline` token instead of `NonLogicalNewline`.
6. If the re-lexing gives a different token than the current one, the
token source needs to update it's token collection to remove all the
tokens which comes after the new current position.
It turns out that the list parsing isn't that happy with the results so
it requires some re-arranging such that the following two errors are
raised correctly:
1. Expected comma
2. Recovery context error
For (1), the following scenarios needs to be considered:
* Missing comma between two elements
* Half parsed element because the grammar doesn't allow it (for example,
named expressions)
For (2), the following scenarios needs to be considered:
1. If the parser is at a comma which means that there's a missing
element otherwise the comma would've been consumed by the first `eat`
call above. And, the parser doesn't take the re-lexing route on a comma
token.
2. If it's the first element and the current token is not a comma which
means that it's an invalid element.
resolves: #11640
## Test Plan
- [x] Update existing test snapshots and validate them
- [x] Add additional test cases specific to the re-lexing logic and
validate the snapshots
- [x] Run the fuzzer on 3000+ valid inputs
- [x] Run the fuzzer on invalid inputs
- [x] Run the parser on various open source projects
- [x] Make sure the ecosystem changes are none
## Summary
This PR adds a new enum to determine the kind of terminator token i.e.,
is it actually terminates the list or is it used for error recovery.
This is important because the parser should take the error recovery
route in case the terminator token is used for better error recovery.
This will then try to re-lex the token if it's the case.
I haven't updated any reference to use this new enum as otherwise it'll
update the snapshots. I plan to do that in a follow-up PR so that it's
easier to reason about.
## Test plan
`cargo insta test`
## Summary
This PR separates the terminator token for f-string elements depending
on the context. A list of f-string element can occur either in a regular
f-string or a format spec of an f-string. The terminator token is
different depending on that context.
## Test Plan
`cargo insta test` and verify the updated snapshots.
## Summary
This PR re-uses the `ruff_python_trivia::is_python_whitespace` in the
lexer instead of defining its own. This was mainly to avoid circular
dependency which was resolved in #11261.
## Summary
This PR updates the parser to remove building the `CommentRanges` and
instead it'll be built by the linter and the formatter when it's
required.
For the linter, it'll be built and owned by the `Indexer` while for the
formatter it'll be built from the `Tokens` struct and passed as an
argument.
## Test Plan
`cargo insta test`
## Summary
This PR updates the return type of `parse_type_annotation` from `Expr`
to `Parsed<ModExpression>`. This is to allow accessing the tokens for
the parsed sub-expression in the follow-up PR.
## Test Plan
`cargo insta test`
## Summary
This PR fixes a bug where the lexer didn't consider the BOM into the
start offset.
fixes: #11731
## Test Plan
Add multiple test cases which involves BOM character in the source for
the lexer and verify the snapshot.
## Summary
This PR updates the lexer checkpoint to store the cursor offset instead
of cloning the cursor itself. This reduces the size of `LexerCheckpoint`
from 136 to 112 bytes and also removes the need for lifetime.
## Test Plan
`cargo insta test`
