Variable popup on debugging doesn't show value

[nachograffione]

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  • 1.80.1
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  • v0.39.0
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Describe the bug

A clear and concise description of what the bug.
A clear and concise description of what you expected to happen.

When I'm debugging, if I hover over a struct field in my code I expect to see its value (if it has something, of course).
If I've written the dot notation expression in one line, the popup shows the value (OK).
If I've written it in multiple lines, the popup shows the field description (bug).

Steps to reproduce the behavior:

1. Debug this code with a breakpoint in the 2nd print.

package main

import "fmt"

type StructA struct {
	StructB StructB
}

type StructB struct {
	C int
}

func main() {
	s := StructA{
		StructB: StructB{
			C: 1,
		},
	}
	fmt.Println(s.StructB.C)
	fmt.Println(s.
		StructB.C)
}

2. Hover on StructB at the 1st print. You'll see the value. (OK)
3. Hover on StructB at the 2nd print. You'll see the description. (bug)

Screenshots or recordings

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[suzmue]

Thanks for reporting this issue!

The hovers are computed through an evaluate request with a string determined by VS Code. With the new line, the only information that is sent to the debug adapter is StructB.

2023-07-20T13:53:40-06:00 debug layer=dap [<- from client]{"seq":13,"type":"request","command":"evaluate","arguments":{"expression":"s.StructB","frameId":1000,"context":"hover","format":{}}}
2023-07-20T13:53:40-06:00 debug layer=dap [-> to client]{"seq":0,"type":"response","request_seq":13,"success":true,"command":"evaluate","body":{"result":"main.StructB {C: 1}","type":"main.StructB","presentationHint":{},"variablesReference":1002}}
2023-07-20T13:53:40-06:00 debug layer=dap [-> to client]{"seq":0,"type":"response","request_seq":14,"success":true,"command":"variables","body":{"variables":[{"name":"C","value":"1","type":"int","presentationHint":{},"evaluateName":"(s.StructB).C","variablesReference":0}]}}
2023-07-20T13:53:43-06:00 debug layer=dap [<- from client]{"seq":15,"type":"request","command":"evaluate","arguments":{"expression":"StructB","frameId":1000,"context":"hover","format":{}}}
2023-07-20T13:53:43-06:00 debug layer=dap Unable to evaluate expression: could not find symbol value for StructB
2023-07-20T13:53:43-06:00 debug layer=dap [-> to client]{"seq":0,"type":"response","request_seq":15,"success":false,"command":"evaluate","message":"Unable to evaluate expression","body":{"error":{"id":2009,"format":"Unable to evaluate expression: could not find symbol value for StructB","showUser":false}}}

The vscode-go extension can implement the EvaluatableExpressionProvider to provide the evaluate expressions:(https://code.visualstudio.com/updates/v1_43#_debugger-extension-api)

Here is a link to comment on a vscode issue describing the solution and providing links to the examples: microsoft/vscode#146191 (comment)