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negate: replace special case with parens

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v0: negate: add parens for negative values
    Before this patch -(-1) was formatted to --1, but this is not valid
    syntax.
v2: replace special case with parens, otherwise formatting of -(-(-1))
    will be unstable, in v0 it was formatted to -(1) but -(1) is
    formatted to -1 [1].

  [1]: https://clickhouse-test-reports.s3.yandex.net/24427/4512460aeb02fec557c558eee3f8291a6297efb2/fuzzer_asan/fuzzer.log
This commit is contained in:
Azat Khuzhin 2021-05-23 16:34:31 +03:00
parent 04be5437d9
commit 9242654231
3 changed files with 38 additions and 54 deletions
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72
src/Parsers/ASTFunction.cpp
View File

@ -231,68 +231,32 @@ void ASTFunction::formatImplWithoutAlias(const FormatSettings & settings, Format
}
const auto * literal = arguments->children[0]->as<ASTLiteral>();
/* A particularly stupid case. If we have a unary minus before
* a literal that is a negative number "-(-1)" or "- -1", this
* can not be formatted as `--1`, since this will be
* interpreted as a comment. Instead, negate the literal
* in place. Another possible solution is to use parentheses,
* but the old comment said it is impossible, without mentioning
* the reason. We should also negate the nonnegative literals,
* for symmetry. We print the negated value without parentheses,
* because they are not needed around a single literal. Also we
* use formatting from FieldVisitorToString, so that the type is
* preserved (e.g. -0. is printed with trailing period).
*/
if (literal && name == "negate")
{
written = applyVisitor(
[&settings](const auto & value)
// -INT_MAX is negated to -INT_MAX by the negate()
// function, so we can implement this behavior here as
// well. Technically it is an UB to perform such negation
// w/o a cast to unsigned type.
NO_SANITIZE_UNDEFINED
{
using ValueType = std::decay_t<decltype(value)>;
if constexpr (is_decimal_field<ValueType>)
{
// The parser doesn't create decimal literals, but
// they can be produced by constant folding or the
// fuzzer. Decimals are always signed, so no need
// to deduce the result type like we do for ints.
const auto int_value = value.getValue().value;
settings.ostr << FieldVisitorToString{}(ValueType{
-int_value,
value.getScale()});
}
else if constexpr (std::is_arithmetic_v<ValueType>)
{
using ResultType = typename NumberTraits::ResultOfNegate<ValueType>::Type;
settings.ostr << FieldVisitorToString{}(
-static_cast<ResultType>(value));
return true;
}
return false;
},
literal->value);
if (written)
{
break;
}
}
const auto * function = arguments->children[0]->as<ASTFunction>();
bool negate = name == "negate";
// negate always requires parentheses, otherwise -(-1) will be printed as --1
bool negate_need_parens = negate && (literal || (function && function->name == "negate"));
// We don't need parentheses around a single literal.
if (!literal && frame.need_parens)
bool need_parens = !literal && frame.need_parens && !negate_need_parens;
// do not add extra parentheses for functions inside negate, i.e. -(-toUInt64(-(1)))
if (negate_need_parens)
nested_need_parens.need_parens = false;
if (need_parens)
settings.ostr << '(';
settings.ostr << (settings.hilite ? hilite_operator : "") << func[1] << (settings.hilite ? hilite_none : "");
if (negate_need_parens)
settings.ostr << '(';
arguments->formatImpl(settings, state, nested_need_parens);
written = true;
if (!literal && frame.need_parens)
if (negate_need_parens)
settings.ostr << ')';
if (need_parens)
settings.ostr << ')';
break;

13
tests/queries/0_stateless/01881_negate_formatting.reference Normal file
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@ -0,0 +1,13 @@
-- { echo }
EXPLAIN SYNTAX SELECT -1;
SELECT -1
EXPLAIN SYNTAX SELECT -(1);
SELECT -(1)
EXPLAIN SYNTAX SELECT -(-(1));
SELECT -(-(1))
EXPLAIN SYNTAX SELECT -(-(-(1)));
SELECT -(-(-(1)))
EXPLAIN SYNTAX SELECT -(-(-1));
SELECT -(-(-1))
EXPLAIN SYNTAX SELECT -(-toUInt64(-(1)));
SELECT -(-toUInt64(-(1)))

7
tests/queries/0_stateless/01881_negate_formatting.sql Normal file
View File

@ -0,0 +1,7 @@
-- { echo }
EXPLAIN SYNTAX SELECT -1;
EXPLAIN SYNTAX SELECT -(1);
EXPLAIN SYNTAX SELECT -(-(1));
EXPLAIN SYNTAX SELECT -(-(-(1)));
EXPLAIN SYNTAX SELECT -(-(-1));
EXPLAIN SYNTAX SELECT -(-toUInt64(-(1)));