Node debugger fails to stop after step over when smartstep is on

[kkeri]

This is a rewording of my previous issue #37670 where I focused on delay, but the real issue is that the debugger fails to stop after a step over command when smartstep is enabled. The failure is not related to code complexity. It occurs when mapped and non-mapped sources play together.

• Node version: v8.7.0
• VSCode Version: Code 1.17.2 (b813d12, 2017-10-16T13:59:46.104Z)
• OS Version: Windows_NT x64 10.0.15063
• Extensions:

Extension	Author (truncated)	Version
ohm	att	1.0.0
vscode-eslint	dba	1.4.2
easy-icons	jam	0.3.1
vscode-codemetrics	kis	1.10.0
extension-manifest-editor	ms-	0.1.5
cpptools	ms-	0.14.0
debugger-for-chrome	msj	3.5.0

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Reproduces without extensions: Yes

Steps to Reproduce:

I created a minimal project and shared it on Github. Please clone it and follow the steps below.

https://github.com/kkeri/vscode-smartstep-issue

• open the project directory in VS Code
• execute npm install and npm run build in a terminal window
• open test/test.js in the editor (which is an unmapped source)
• set a breakpoint on line 11 (which calls a trivial function in a mapped source)
• choose the "launch with smartstep" launch configuration
• start debugging
• when the debugger stops at the breakpoint, press F10 (step over)

Expected behavior: the debugger stops on line 12.
Actual behavior: the debugger doesn't stop until the program terminates.

When the program is debugged with the "launch without smartstep" configuration though, everything goes well. To reproduce another variation of the issue do the following:

• set a breakpoint on line 11
• start debugging
• when the debugger stops at the breakpoint, start pressing F11 repeatedly.

Edit: the debugger correctly steps into src/mapped.js.
Although at src/mapped.js:3 the debugger will "lose the thread" and run the program until termination.

Edit: fix line numbers

[roblourens]

I think my comment at #37670 (comment) explains this. This just sounds like smartStep working as currently designed.

smartStep is currently less "smart" than it maybe could be. There's a little discussion in microsoft/vscode-chrome-debug-core#245 about it. Maybe it could only step over unmapped lines in files with sourcemaps, or be disabled for a file with a breakpoint, or something else. Maybe that's closer to your expectation.

[kkeri]

Thanks for your comments. Yes, they explain what happens and why.