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Debugger.setInstrumentationBreakpoint is broken #31138
Description
Activity
@nodejs/v8-inspector
Any updates for this issue?
Hi! I fixed the issue in V8 (commit, issue in V8) - turns out it doesn't work only with CJS modules.
So when the dependency on V8 is updated this issue should be fixed.
Why it happens
Node's CJS loader compiles modules via
v8::ScriptCompiler::CompileFunction- it passes the raw module text plus a parameter list -exports, require, module, __filename, __dirname(seeGetCJSParameters).Compiler::GetWrappedFunctionthroughParsersynthesizes an eval-style outer scope whose only statement is a return of the wrapped function literal.
Conceptually, the AST V8 ends up parsing looks like this:// before console.log('hello from CJS module'); // after return function (exports, require, module, __filename, __dirname) { console.log('hello from CJS module'); };
Two SFIs come out of that compilation:
- Script (is_wrapped == true)
- SFI#1 is_toplevel, bytecode =
return <fn #2>(never called, but we set breakpoint there!) - SFI#2 is_wrapped, bytecode =
console.log(...)(this one actually runs)
- SFI#1 is_toplevel, bytecode =
GetWrappedFunctionreturns SFI#2 to Node, Node invokes it,hello from moduleis logged.And finally, when we send an instrumentation breakpoint request,
Script::SetInstrumentationBreakpointwalks the SFIs and picks the firstis_toplevel()one - SFI#1. But SFI#1 is the syntheticreturn <FUNCTION>wrapper that nobody ever calls.Reacted by Dmitry MakhnevReacted by Dmitry Makhnev- Script (is_wrapped == true)
Newly added
Debugger.setInstrumentationBreakpointinspector API doesn't work for me. Changes were introduced for request #24687. The same API works fine in Chrome.I've created a test #31137. Breakpoints for scripts with sourcemaps only don't work either. If I use the protocol incorrectly, please let me know which additional methods should be called.