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Remove impossible states from version-comparison representation (#4696)

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Charlie Marsh 2023-05-28 18:08:40 -04:00 • committed by GitHub
parent 79b35fc3cc
commit dbeadd99a8
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1 changed files with 138 additions and 102 deletions
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240
crates/ruff/src/rules/pyupgrade/rules/outdated_version_block.rs
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@ -32,64 +32,99 @@ impl AlwaysAutofixableViolation for OutdatedVersionBlock {
}
}
/// The metadata for a version-comparison block.
#[derive(Debug)]
struct BlockMetadata {
/// The first non-whitespace token in the block.
starter: Tok,
/// The location of the first `elif` token, if any.
elif: Option<TextSize>,
/// The location of the `else` token, if any.
else_: Option<TextSize>,
/// The first `if` or `elif` token in the block, used to signal the start of the
/// version-comparison block.
leading_token: StartToken,
/// The first `elif` or `else` token following the start token, if any, used to signal the end
/// of the version-comparison block.
trailing_token: Option<EndToken>,
}
impl BlockMetadata {
const fn new(starter: Tok, elif: Option<TextSize>, else_: Option<TextSize>) -> Self {
Self {
starter,
elif,
else_,
/// The set of tokens that can start a block, i.e., the first token in an `if` statement.
#[derive(Debug)]
enum StartTok {
If,
Elif,
}
impl StartTok {
fn from_tok(tok: &Tok) -> Option<Self> {
match tok {
Tok::If => Some(Self::If),
Tok::Elif => Some(Self::Elif),
_ => None,
}
}
}
#[derive(Debug)]
struct StartToken {
tok: StartTok,
range: TextRange,
}
/// The set of tokens that can end a block, i.e., the first token in the subsequent `elif` or `else`
/// branch that follows an `if` or `elif` statement.
#[derive(Debug)]
enum EndTok {
Elif,
Else,
}
impl EndTok {
fn from_tok(tok: &Tok) -> Option<Self> {
match tok {
Tok::Elif => Some(Self::Elif),
Tok::Else => Some(Self::Else),
_ => None,
}
}
}
#[derive(Debug)]
struct EndToken {
tok: EndTok,
range: TextRange,
}
fn metadata<T>(locator: &Locator, located: &T, body: &[Stmt]) -> Option<BlockMetadata>
where
T: Ranged,
{
indentation(locator, located)?;
let mut starter = None;
let mut elif = None;
let mut else_ = None;
let body_end = body.last().map(Ranged::end).unwrap();
for (tok, range) in lexer::lex_starts_at(
let mut iter = lexer::lex_starts_at(
locator.slice(located.range()),
Mode::Module,
located.start(),
)
.flatten()
.filter(|(tok, _)| matches!(tok, Tok::If | Tok::Elif | Tok::Else))
{
if starter.is_none() {
starter = Some(tok.clone());
} else if range.start() < body_end {
// Continue until the end of the `if` body, thus ensuring that we don't
// accidentally pick up an `else` or `elif` in the nested block.
continue;
// We only care about the first `elif` or `else` following the `if`.
} else if matches!(tok, Tok::Elif) {
elif = Some(range.start());
break;
} else if matches!(tok, Tok::Else) {
else_ = Some(range.start());
break;
}
}
Some(BlockMetadata::new(starter.unwrap(), elif, else_))
.flatten();
// First the leading `if` or `elif` token.
let (tok, range) = iter.next()?;
let leading_token = StartToken {
tok: StartTok::from_tok(&tok)?,
range,
};
// Skip any tokens until we reach the end of the `if` body.
let body_end = body.last()?.range().end();
// Find the trailing `elif` or `else` token, if any.
let trailing_token = iter
.skip_while(|(_, range)| range.start() < body_end)
.find_map(|(tok, range)| EndTok::from_tok(&tok).map(|tok| EndToken { tok, range }));
Some(BlockMetadata {
leading_token,
trailing_token,
})
}
/// Converts a `BigInt` to a `u32`, if the number is negative, it will return 0
/// Converts a `BigInt` to a `u32`. If the number is negative, it will return 0.
fn bigint_to_u32(number: &BigInt) -> u32 {
let the_number = number.to_u32_digits();
match the_number.0 {
@ -147,11 +182,11 @@ fn compare_version(if_version: &[u32], py_version: PythonVersion, or_equal: bool
fn fix_py2_block(
checker: &mut Checker,
stmt: &Stmt,
body: &[Stmt],
orelse: &[Stmt],
block: &BlockMetadata,
) -> Option<Fix> {
if orelse.is_empty() {
let leading_token = &block.leading_token;
let Some(trailing_token) = &block.trailing_token else {
// Delete the entire statement. If this is an `elif`, know it's the only child
// of its parent, so avoid passing in the parent at all. Otherwise,
// `delete_stmt` will erroneously include a `pass`.
@ -160,7 +195,7 @@ fn fix_py2_block(
let defined_in = checker.semantic_model().stmt_parent();
return match delete_stmt(
defined_by,
if block.starter == Tok::If {
if matches!(block.leading_token.tok, StartTok::If) {
defined_in
} else {
None
@ -180,59 +215,64 @@ fn fix_py2_block(
None
}
};
}
};
// If we only have an `if` and an `else`, dedent the `else` block.
if block.starter == Tok::If && block.elif.is_none() {
let start = orelse.first().unwrap();
let end = orelse.last().unwrap();
if indentation(checker.locator, start).is_none() {
// Inline `else` block (e.g., `else: x = 1`).
#[allow(deprecated)]
Some(Fix::unspecified(Edit::range_replacement(
checker
.locator
.slice(TextRange::new(start.start(), end.end()))
.to_string(),
stmt.range(),
)))
} else {
indentation(checker.locator, stmt)
.and_then(|indentation| {
adjust_indentation(
TextRange::new(checker.locator.line_start(start.start()), end.end()),
indentation,
checker.locator,
checker.stylist,
)
.ok()
})
.map(|contents| {
#[allow(deprecated)]
Fix::unspecified(Edit::replacement(
contents,
checker.locator.line_start(stmt.start()),
stmt.end(),
))
})
}
} else {
let mut end_location = orelse.last().unwrap().start();
if block.starter == Tok::If && block.elif.is_some() {
// Turn the `elif` into an `if`.
end_location = block.elif.unwrap() + TextSize::from(2);
} else if block.starter == Tok::Elif {
if let Some(elif) = block.elif {
end_location = elif;
} else if let Some(else_) = block.else_ {
end_location = else_;
match (&leading_token.tok, &trailing_token.tok) {
// If we only have an `if` and an `else`, dedent the `else` block.
(StartTok::If, EndTok::Else) => {
let start = orelse.first()?;
let end = orelse.last()?;
if indentation(checker.locator, start).is_none() {
// Inline `else` block (e.g., `else: x = 1`).
#[allow(deprecated)]
Some(Fix::unspecified(Edit::range_replacement(
checker
.locator
.slice(TextRange::new(start.start(), end.end()))
.to_string(),
stmt.range(),
)))
} else {
end_location = body.last().unwrap().end();
indentation(checker.locator, stmt)
.and_then(|indentation| {
adjust_indentation(
TextRange::new(checker.locator.line_start(start.start()), end.end()),
indentation,
checker.locator,
checker.stylist,
)
.ok()
})
.map(|contents| {
#[allow(deprecated)]
Fix::unspecified(Edit::replacement(
contents,
checker.locator.line_start(stmt.start()),
stmt.end(),
))
})
}
}
#[allow(deprecated)]
Some(Fix::unspecified(Edit::deletion(stmt.start(), end_location)))
(StartTok::If, EndTok::Elif) => {
// If we have an `if` and an `elif`, turn the `elif` into an `if`.
let start_location = leading_token.range.start();
let end_location = trailing_token.range.start() + TextSize::from(2);
#[allow(deprecated)]
Some(Fix::unspecified(Edit::deletion(
start_location,
end_location,
)))
}
(StartTok::Elif, _) => {
// If we have an `elif`, delete up to the `else` or the end of the statement.
let start_location = leading_token.range.start();
let end_location = trailing_token.range.start();
#[allow(deprecated)]
Some(Fix::unspecified(Edit::deletion(
start_location,
end_location,
)))
}
}
}
@ -244,13 +284,12 @@ fn fix_py3_block(
body: &[Stmt],
block: &BlockMetadata,
) -> Option<Fix> {
match block.starter {
Tok::If => {
match block.leading_token.tok {
StartTok::If => {
// If the first statement is an if, use the body of this statement, and ignore
// the rest.
let start = body.first().unwrap();
let end = body.last().unwrap();
let start = body.first()?;
let end = body.last()?;
if indentation(checker.locator, start).is_none() {
// Inline `if` block (e.g., `if ...: x = 1`).
#[allow(deprecated)]
@ -282,10 +321,10 @@ fn fix_py3_block(
})
}
}
Tok::Elif => {
StartTok::Elif => {
// Replace the `elif` with an `else, preserve the body of the elif, and remove
// the rest.
let end = body.last().unwrap();
let end = body.last()?;
let text = checker.locator.slice(TextRange::new(test.end(), end.end()));
#[allow(deprecated)]
Some(Fix::unspecified(Edit::range_replacement(
@ -293,7 +332,6 @@ fn fix_py3_block(
stmt.range(),
)))
}
_ => None,
}
}
@ -336,9 +374,7 @@ pub(crate) fn outdated_version_block(
let mut diagnostic = Diagnostic::new(OutdatedVersionBlock, stmt.range());
if checker.patch(diagnostic.kind.rule()) {
if let Some(block) = metadata(checker.locator, stmt, body) {
if let Some(fix) =
fix_py2_block(checker, stmt, body, orelse, &block)
{
if let Some(fix) = fix_py2_block(checker, stmt, orelse, &block) {
diagnostic.set_fix(fix);
}
}
@ -369,7 +405,7 @@ pub(crate) fn outdated_version_block(
let mut diagnostic = Diagnostic::new(OutdatedVersionBlock, stmt.range());
if checker.patch(diagnostic.kind.rule()) {
if let Some(block) = metadata(checker.locator, stmt, body) {
if let Some(fix) = fix_py2_block(checker, stmt, body, orelse, &block) {
if let Some(fix) = fix_py2_block(checker, stmt, orelse, &block) {
diagnostic.set_fix(fix);
}
}