How do I evaluate expressions while debugging in VS Code?

Question

I am using vscode to build my golang gin project.

I go to debugging mod and can not do evaluate expressions.

I want to go some line and evaluate that see what happened in that monent.

Like eclipse ctrl+shift+i or idea ctrl+alt+f8

Quick evaluate expression.

I also see this

Eclipse inspection (Ctrl + Shift + I) equivalent in IntelliJ IDEA (Community Edition)

Watch window or evaluate expressions while debugging in VS Code?

func main() {
    
    router := gin.Default()
    router.GET("/user/:name", func(c *gin.Context) {
    name := c.Param("name")
    c.String(http.StatusOK, name, 1, 2, 3, 4)

})

when the debugger line in name := c.Param("name")

I try to use the bottom of vscode window and when I type this code into the command it will return

but if I type name it will return the right string for me.

Failed to eval expression: { "Expr": "c.Param("name")", "Scope": { "goroutineID": 34, "frame": 1 }, "Cfg": { "followPointers": true, "maxVariableRecurse": 1, "maxStringLen": 64, "maxArrayValues": 64, "maxStructFields": -1 } } Eval error: function calls not allowed without using 'call'

Unfortunately I think this is a limitation of the language's debugging tools: https://github.com/Microsoft/vscode-go/issues/2225 It seems like pretty basic debugging functionality to be missing... — JHS, Aug 04 '19 at 03:41

score 57 · Answer 1 · edited Aug 18 '21 at 22:43

57

For the ones coming here at 2020+, it is now possible to call a function. The syntax is:

call functionToBeCalled(arg1, arg2)

In the question ask for running an assignation, you can also set a variable

call variable = newValue

Source: https://github.com/golang/vscode-go/issues/100

edited Aug 18 '21 at 22:43

AskYous

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answered Jan 04 '21 at 15:36

Javier Dottori

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I added this to the Debug Console and it worked: ```functioToBeCalled(arg1, arg2)``` – Dennis Barzanoff Jan 05 '21 at 19:10
Thanks , I already using jetbrain goland for one year. – 石荒人 Jan 11 '21 at 08:36
You can also set a property of an object in the debug console: `call myObject.myProperty="some new property value"` – Ed J Feb 09 '21 at 05:08
@石荒人 are you able to call a function in jetbrain goland while execution is stopped in a debug break point? – Jairo Lozano Jun 28 '21 at 23:08

Deine Freunde · Answer 2 · 2019-11-06T16:06:29.350

5

This isn't possible right now as more complex evaluations have only been added to the Delve debugger recently. You might want to follow these two Github issues:

Add ability to safely call functions #119

Function calls via delve 'call' are not supported #2655

edited Nov 06 '19 at 16:06

answered Nov 05 '19 at 22:09

Deine Freunde

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score 3 · Answer 3 · answered Mar 04 '23 at 16:25

3

Type your expression here or select code in source file, right click and select Evaluate in Debug Console.

answered Mar 04 '23 at 16:25

Jean-Pierre Schnyder

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I tried this, but I got the error: "Unable to evaluate expression: function calls not allowed without using 'call'". Do you have a solution for this? – Alvaro Leandro Cavalcante Mar 07 '23 at 13:08

score 1 · Answer 4 · answered Dec 08 '22 at 13:28

If you run into an error like "call not at safe point", make sure you've stopped at a breakpoint which is not on a line declaring a function, but inside the body of a function.

Apparently function declaration lines are not a safe point for the debugger

score -2 · Answer 5 · answered Dec 25 '22 at 15:49

-2

I'm running VS Code 1.72.2 and it's possible to run expressions directly inside the Debug Console.

Just type an expression and press Enter. In the example below I typed req.header:

answered Dec 25 '22 at 15:49

vovahost

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How do I evaluate expressions while debugging in VS Code?

5 Answers5