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[debug] Only apply TDZ 'value unavailable' logic for let/const

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This CL refines https://crrev.com/c/3829539 to only apply to let and
const declared variables. `var`s should stay `undefined`.

R=jarin@chromium.org

Bug: chromium:1328681
Change-Id: I35778c89fb04439348a4f6aebcdeb2db6234f9d0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3848960
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82640}
This commit is contained in:
Simon Zünd 2022-08-23 07:54:55 +02:00 committed by V8 LUCI CQ
parent 7e98192461
commit 85561d6616
3 changed files with 46 additions and 11 deletions
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3
src/debug/debug-scopes.cc
View File

@ -878,7 +878,8 @@ bool ScopeIterator::VisitLocals(const Visitor& visitor, Mode mode,
current_scope_->AsDeclarationScope()->arguments() == var) {
continue;
}
} else if (value->IsUndefined(isolate_) &&
} else if (IsLexicalVariableMode(var->mode()) &&
value->IsUndefined(isolate_) &&
GetSourcePosition() != kNoSourcePosition &&
GetSourcePosition() <= var->initializer_position()) {
// Variables that are `undefined` could also mean an elided hole

3
test/inspector/debugger/value-unavailable-scopes-expected.txt
View File

@ -8,3 +8,6 @@ variable y correctly reported as <value_unavailable>
Running test: testUnusedValueInTdz
variable y correctly reported as <value_unavailable>
Running test: testVarStaysUndefined
variable y correctly reported as <undefined>

51
test/inspector/debugger/value-unavailable-scopes.js
View File

@ -38,23 +38,34 @@ function unusedValInTdz() {
debugger;
let y = 1;
}
function varStaysUndefined() {
debugger;
var y = 42;
}
`);
Protocol.Debugger.onPaused(async ({params: {callFrames: [{scopeChain}]}}) => {
async function findLocalVariable(name, scopeChain) {
for (const scope of scopeChain) {
if (scope.type !== 'local') continue;
const {result: {result: variables}} =
await Protocol.Runtime.getProperties({objectId: scope.object.objectId});
for (const variable of variables) {
if (variable.name !== 'y') continue;
if ('value' in variable || 'get' in variable || 'set' in variable) {
InspectorTest.log(
'FAIL: variable y was expected to be reported as <value_unavailable>');
} else {
InspectorTest.log(
'variable y correctly reported as <value_unavailable>');
}
const variable = variables.find(variable => variable.name === name);
if (!variable) {
InspectorTest.log(`FAIL: variable ${name} not found in local scope`);
}
return variable;
}
}
Protocol.Debugger.onPaused(async ({ params: { callFrames: [{ scopeChain }] } }) => {
const variable = await findLocalVariable('y', scopeChain);
if ('value' in variable || 'get' in variable || 'set' in variable) {
InspectorTest.log(
'FAIL: variable y was expected to be reported as <value_unavailable>');
} else {
InspectorTest.log(
'variable y correctly reported as <value_unavailable>');
}
await Protocol.Debugger.resume();
});
@ -95,4 +106,24 @@ InspectorTest.runAsyncTestSuite([
Protocol.Debugger.disable(),
]);
},
async function testVarStaysUndefined() {
await Promise.all([
Protocol.Runtime.enable(),
Protocol.Debugger.enable(),
]);
Protocol.Runtime.evaluate({ expression: 'varStaysUndefined()' });
const { params: { callFrames: [{ scopeChain }] } } = await Protocol.Debugger.oncePaused();
const variable = await findLocalVariable('y', scopeChain);
if ('value' in variable && variable.value.type === 'undefined') {
InspectorTest.log('variable y correctly reported as <undefined>');
} else {
InspectorTest.log('FAIL: variable y was expected to be reported as <undefined>');
}
await Protocol.Debugger.resume();
await Promise.all([
Protocol.Runtime.disable(),
Protocol.Debugger.disable(),
]);
},
]);