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Correct Regular Expressions Behavior Related to Annex B #58320

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merged 12 commits into from
May 29, 2024
Merged

Correct Regular Expressions Behavior Related to Annex B #58320

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e049438
Correct RegExp Behavior Related to Annex B
graphemecluster Apr 25, 2024
358eb30
Fix Comment
graphemecluster Apr 25, 2024
8facb0a
Correct Quantifiability of `{1` in Annex B
graphemecluster Apr 27, 2024
f5c0b60
`\c` is an Annex B thing
graphemecluster Apr 27, 2024
cff993f
Add Tests
graphemecluster Apr 27, 2024
603c3cf
Merge from main
rbuckton May 16, 2024
2e62d25
Apply Suggested Changes
graphemecluster May 21, 2024
ed08ef7
Apply Suggested Changes
graphemecluster May 24, 2024
8b67d77
Merge branch 'main' into regex-syntax-check-annexB
graphemecluster May 24, 2024
b48f0d0
Provide User-Friendly Errors for Decimal Escapes Inside Character Cla…
graphemecluster May 24, 2024
c72f92f
Fix Behavior Related to `namedCaptureGroups`
graphemecluster May 28, 2024
70a3214
Clarify why nested character classes should not be considered in the …
graphemecluster May 28, 2024
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78 changes: 50 additions & 28 deletions src/compiler/scanner.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -1556,9 +1556,7 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
tokenFlags |= TokenFlags.ContainsInvalidEscape;
if (isRegularExpression || shouldEmitInvalidEscapeError) {
const code = parseInt(text.substring(start + 1, pos), 8);
if (isRegularExpression !== "annex-b") {
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Since this was the only place we check for "annex-b", we can make isRegularExpression a boolean again.

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@graphemecluster graphemecluster May 23, 2024 •
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I thought the same too, but there is a isRegularExpression === true at the bottom

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This probably is worth being refactored, since shouldEmitInvalidEscapeError does not explain itself but is taken over to mean anyUnicodeMode for regular expressions. But this will be yet another PR I guess.

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Do you use an enum for such a case?

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Ah, I found that I once created a enum named ClassSetExpressionType.

error(Diagnostics.Octal_escape_sequences_are_not_allowed_Use_the_syntax_0, start, pos - start, "\\x" + code.toString(16).padStart(2, "0"));
}
error(Diagnostics.Octal_escape_sequences_are_not_allowed_Use_the_syntax_0, start, pos - start, "\\x" + code.toString(16).padStart(2, "0"));
return String.fromCharCode(code);
}
return text.substring(start, pos);
Expand Down Expand Up @@ -2426,6 +2424,7 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
// Quickly get to the end of regex such that we know the flags
let p = tokenStart + 1;
let inEscape = false;
let namedCaptureGroups = false;
// Although nested character classes are allowed in Unicode Sets mode,
// an unescaped slash is nevertheless invalid even in a character class in Unicode mode.
// Additionally, parsing nested character classes will misinterpret regexes like `/[[]/`
Expand Down Expand Up @@ -2469,6 +2468,15 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
else if (ch === CharacterCodes.closeBracket) {
inCharacterClass = false;
}
else if (
ch === CharacterCodes.openParen
&& charCodeChecked(p + 1) === CharacterCodes.question
&& charCodeChecked(p + 2) === CharacterCodes.lessThan
&& charCodeChecked(p + 3) !== CharacterCodes.equals
&& charCodeChecked(p + 3) !== CharacterCodes.exclamation
) {
namedCaptureGroups = true;
}
p++;
}
const isUnterminated = !!(tokenFlags & TokenFlags.Unterminated);
Expand Down Expand Up @@ -2505,7 +2513,7 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
const saveEnd = end;
pos = tokenStart + 1;
end = endOfBody;
scanRegularExpressionWorker(regExpFlags, isUnterminated, /*annexB*/ true);
scanRegularExpressionWorker(regExpFlags, isUnterminated, /*annexB*/ true, namedCaptureGroups);
tokenStart = saveTokenStart;
tokenFlags = saveTokenFlags;
pos = savePos;
Expand All @@ -2517,7 +2525,7 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
return token;
}

function scanRegularExpressionWorker(regExpFlags: RegularExpressionFlags, isUnterminated: boolean, annexB: boolean) {
function scanRegularExpressionWorker(regExpFlags: RegularExpressionFlags, isUnterminated: boolean, annexB: boolean, namedCaptureGroups: boolean) {
// Why var? It avoids TDZ checks in the runtime which can be costly.
// See: https://github.com/microsoft/TypeScript/issues/52924
/* eslint-disable no-var */
Expand All @@ -2527,10 +2535,9 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
/** Grammar parameter */
var unicodeMode = !!(regExpFlags & RegularExpressionFlags.UnicodeMode);

if (unicodeMode) {
// Annex B treats any unicode mode as the strict syntax.
annexB = false;
}
// Regular expressions are checked more strictly when either in 'u' or 'v' mode, or
// when not using the looser interpretation of the syntax from ECMA-262 Annex B.
var anyUnicodeModeOrNonAnnexB = unicodeMode || !annexB;

/** @see {scanClassSetExpression} */
var mayContainStrings = false;
Expand Down Expand Up @@ -2626,7 +2633,7 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
case CharacterCodes.exclamation:
pos++;
// In Annex B, `(?=Disjunction)` and `(?!Disjunction)` are quantifiable
isPreviousTermQuantifiable = annexB;
isPreviousTermQuantifiable = !anyUnicodeModeOrNonAnnexB;
break;
case CharacterCodes.lessThan:
const groupNameStart = pos;
Expand Down Expand Up @@ -2675,6 +2682,10 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
const digitsStart = pos;
scanDigits();
const min = tokenValue;
if (!anyUnicodeModeOrNonAnnexB && !min) {
isPreviousTermQuantifiable = true;
break;
}
if (charCodeChecked(pos) === CharacterCodes.comma) {
pos++;
scanDigits();
Expand All @@ -2684,26 +2695,32 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
error(Diagnostics.Incomplete_quantifier_Digit_expected, digitsStart, 0);
}
else {
if (unicodeMode) {
error(Diagnostics.Unexpected_0_Did_you_mean_to_escape_it_with_backslash, start, 1, String.fromCharCode(ch));
}
error(Diagnostics.Unexpected_0_Did_you_mean_to_escape_it_with_backslash, start, 1, String.fromCharCode(ch));
isPreviousTermQuantifiable = true;
break;
}
}
if (max && Number.parseInt(min) > Number.parseInt(max)) {
else if (max && Number.parseInt(min) > Number.parseInt(max) && (anyUnicodeModeOrNonAnnexB || charCodeChecked(pos) === CharacterCodes.closeBrace)) {
error(Diagnostics.Numbers_out_of_order_in_quantifier, digitsStart, pos - digitsStart);
}
}
else if (!min) {
if (unicodeMode) {
if (anyUnicodeModeOrNonAnnexB) {
error(Diagnostics.Unexpected_0_Did_you_mean_to_escape_it_with_backslash, start, 1, String.fromCharCode(ch));
}
isPreviousTermQuantifiable = true;
break;
}
scanExpectedChar(CharacterCodes.closeBrace);
pos--;
if (charCodeChecked(pos) !== CharacterCodes.closeBrace) {
if (anyUnicodeModeOrNonAnnexB) {
error(Diagnostics._0_expected, pos, 0, String.fromCharCode(CharacterCodes.closeBrace));
pos--;
}
else {
isPreviousTermQuantifiable = true;
break;
}
}
// falls through
case CharacterCodes.asterisk:
case CharacterCodes.plus:
Expand Down Expand Up @@ -2744,7 +2761,7 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
// Assume what starting from the character to be outside of the regex
return;
}
if (unicodeMode || ch === CharacterCodes.closeParen) {
if (anyUnicodeModeOrNonAnnexB || ch === CharacterCodes.closeParen) {
error(Diagnostics.Unexpected_0_Did_you_mean_to_escape_it_with_backslash, pos, 1, String.fromCharCode(ch));
}
pos++;
Expand Down Expand Up @@ -2801,7 +2818,7 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
scanGroupName(/*isReference*/ true);
scanExpectedChar(CharacterCodes.greaterThan);
}
else if (unicodeMode) {
else if (namedCaptureGroups) {
error(Diagnostics.k_must_be_followed_by_a_capturing_group_name_enclosed_in_angle_brackets, pos - 2, 2);
}
break;
Expand Down Expand Up @@ -2851,10 +2868,10 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
pos++;
return String.fromCharCode(ch & 0x1f);
}
if (unicodeMode) {
if (anyUnicodeModeOrNonAnnexB) {
error(Diagnostics.c_must_be_followed_by_an_ASCII_letter, pos - 2, 2);
}
else if (atomEscape && annexB) {
else if (atomEscape) {
// Annex B treats
//
// ExtendedAtom : `\` [lookahead = `c`]
Expand Down Expand Up @@ -2887,7 +2904,7 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
return "\\";
}
pos--;
return scanEscapeSequence(/*shouldEmitInvalidEscapeError*/ unicodeMode, /*isRegularExpression*/ annexB ? "annex-b" : true);
return scanEscapeSequence(/*shouldEmitInvalidEscapeError*/ unicodeMode, /*isRegularExpression*/ anyUnicodeModeOrNonAnnexB || "annex-b");
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}
}

Expand Down Expand Up @@ -2936,12 +2953,12 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
if (isClassContentExit(ch)) {
return;
}
if (!minCharacter && !annexB) {
if (!minCharacter && anyUnicodeModeOrNonAnnexB) {
error(Diagnostics.A_character_class_range_must_not_be_bounded_by_another_character_class, minStart, pos - 1 - minStart);
}
const maxStart = pos;
const maxCharacter = scanClassAtom();
if (!maxCharacter && !annexB) {
if (!maxCharacter && anyUnicodeModeOrNonAnnexB) {
error(Diagnostics.A_character_class_range_must_not_be_bounded_by_another_character_class, maxStart, pos - maxStart);
continue;
}
Expand Down Expand Up @@ -3437,9 +3454,13 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
error(Diagnostics.Unicode_property_value_expressions_are_only_available_when_the_Unicode_u_flag_or_the_Unicode_Sets_v_flag_is_set, start, pos - start);
}
}
else if (unicodeMode) {
else if (anyUnicodeModeOrNonAnnexB) {
error(Diagnostics._0_must_be_followed_by_a_Unicode_property_value_expression_enclosed_in_braces, pos - 2, 2, String.fromCharCode(ch));
}
else {
pos--;
return false;
}
return true;
}
return false;
Expand Down Expand Up @@ -3481,9 +3502,10 @@ export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean
}
});
forEach(decimalEscapes, escape => {
// in AnnexB, if a DecimalEscape is greater than the number of capturing groups then it is treated as
// either a LegacyOctalEscapeSequence or IdentityEscape
if (!annexB && escape.value > numberOfCapturingGroups) {
// Although a DecimalEscape with a value greater than the number of capturing groups
// is treated as either a LegacyOctalEscapeSequence or an IdentityEscape in Annex B,
// an error is nevertheless reported since it's most likely a mistake.
if (escape.value > numberOfCapturingGroups) {
if (numberOfCapturingGroups) {
error(Diagnostics.This_backreference_refers_to_a_group_that_does_not_exist_There_are_only_0_capturing_groups_in_this_regular_expression, escape.pos, escape.end - escape.pos, numberOfCapturingGroups);
}
Expand Down
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