fix(strings): don't halve backslashes in interpolated string literals#2764
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fix(strings): don't halve backslashes in interpolated string literals#2764truffle-dev wants to merge 1 commit into
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String literals in expressions have their escapes decoded once by the lexer
(processEscapeCharacters), then interpolate() decoded every backslash pair a
second time, halving runs of backslashes (\\ -> \, \\\\ -> \\). Output
from an expression diverged from the same string read as input, and from jq.
interpolate() only needs to treat a backslash pair as an escape when it guards
an interpolation paren (\\( -> literal \(); a standalone pair must pass
through unchanged. Guard the skip on a following '(' so plain backslash runs
survive, mirroring the lexer's own \\( special case.
Fixes mikefarah#2561
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Fixes #2561.
What
A string literal in an expression loses half of any run of backslashes, so the value differs from the same string read as input (and from
jq):Why
Escapes in an expression string literal are processed twice. The lexer runs
processEscapeCharacters, which already decodes\\->\(while deliberately preserving\\(so interpolation escaping survives).interpolate()then collapses every remaining backslash pair a second time, halving runs of backslashes.That second collapse is only needed for the
\\(-> literal\(escape. A standalone pair should pass through untouched. The fix guards the skip on a following(, mirroring the special case the lexer already uses, so\\(still yields a literal\(but plain backslash runs survive.Testing
operator_strings_test.go(\\\\and\\\\\\); both fail onmasterand pass with the fix."\\","Hi \\(.value)", real\(...)interpolation) still pass unchanged.Thanks to the reporter for the clear before/after repro.