Debug: noDebug build does not pass buildFlags correctly

[hyangah]

From the code, I see the buildFlags are passed when running go build

vscode-go/src/debugAdapter/goDebug.ts

Lines 496 to 498 in 0dee1a8

	if (launchArgs.buildFlags) {
	build.push(launchArgs.buildFlags);
	}

However, this flag seems to be lost somewhere. I am not sure who's stripping off this. (node.js? go? something in between?)

How to reproduce:

$ cat main.go
package main

var V = "Bye"

func main() {
	println(V)
}

launch.json

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch",
            "type": "go",
            "request": "launch",
            "mode": "auto",
            "program": "${fileDirname}",
            "buildFlags": "-ldflags='-X main.V=Hello'",
        }
    ]
}

With F5 (run by delve) the program will print 'Hello' as expected.

With Ctrl+F5 (built with go build and then run) the program will print 'Bye'.

If I use "buildFlags": "-ldflags=-X main.V=Hello", Ctrl+F5 works as expected, but that breaks F5 and prevents passing additional flags. (Q. Why is the launch arg's buildFlags is string, not string[]???)

Maybe related - see the following: if I pass quoted "-ldflags=\"-X main.V=Hello\", this flag is lost somewhere and not used in go link step at all. Maybe this could be a mistake on my side, but silently dropping the flag is pretty annoying.

 $ node -e 'require("child_process").execFile("go", ["build", "-o=hello", "-x", "-v", "-ldflags=\"-X main.V=Hello\"", "main.go"], (err, stdout, stderr) => { console.log(err, stdout, stderr) })'
null  WORK=/var/folders/bw/6r6k9d113sv1_vvzk_1kfxbm001py5/T/go-build434685295
mkdir -p $WORK/b001/
cat >$WORK/b001/importcfg.link << 'EOF' # internal
packagefile command-line-arguments=/Users/hakim/Library/Caches/go-build/2a/2af9cb66592368ea7dfeada2ab9ca250d9790d35f4bfdfae36f98fced2a18d69-d
packagefile runtime=/usr/local/go/pkg/darwin_amd64/runtime.a
...
mkdir -p $WORK/b001/exe/
cd .
/usr/local/go/pkg/tool/darwin_amd64/link -o $WORK/b001/exe/a.out -importcfg $WORK/b001/importcfg.link -buildmode=exe -buildid=h5dkj0otzSBVSupackWn/dh-q1CTeFGroUuR0JE04/7nT150mh-SjHVBoGjykk/h5dkj0otzSBVSupackWn -extld=clang /Users/hakim/Library/Caches/go-build/2a/2af9cb66592368ea7dfeada2ab9ca250d9790d35f4bfdfae36f98fced2a18d69-d
/usr/local/go/pkg/tool/darwin_amd64/buildid -w $WORK/b001/exe/a.out # internal
mv $WORK/b001/exe/a.out hello
rm -r $WORK/b001/

cc @suzmue

[AlbinoGeek]

Thank you so much for filing this, I asked in the Slack because I wanted to rule out misconfiguration on my part.
I am not using the nightly version in my experience, just the regular version of the vscode extension.

Multiple columns = multiple versions tested

Program	Version	...
OS	Fedora Workstation 33
gopls	v0.6.0-pre.1	v0.5.x
golang	go1.15.6 linux/amd64
vscode	code-1.52.0-1607640984.el7	code-1.51.1-1605051146.el7
vscode-go	0.19.1	0.18.1

Live Reproduction

With single quotes:

https://github.com/AlbinoGeek/sc2-rsu/blob/15b9f4998bd77d1846873053d8ce129d67ca2d3c/.vscode/launch.json#L15-L15

• Ctrl+F5 runs the program, but without respecting ldflags whatsoever.
• F5 stalls then reports on STOP: Process exiting with code: null

With escaped double-quotes:

https://github.com/AlbinoGeek/sc2-rsu/blob/ab695472bf27718855319bde7a1dbd9275db75dc/.vscode/launch.json#L15-L15

• Ctrl+F5 runs the program, but without respecting ldflags whatsoever.
• F5 reports:

invalid value "\"-X" for flag -ldflags: missing =<value> in <pattern>=<value>
usage: go build [-o output] [-i] [build flags] [packages]
Run 'go help build' for details.
exit status 2
Process exiting with code: 1

[hyangah]

I am afraid the extension has to parse the buildFlags and avoid passing quotes.

The go command silently ignores the flag if quoted (so invalid) value is passed. golang/go#43177

[AlbinoGeek]

Without ldflags I cannot use vscode-go to debug/run my application. Guess it's back to gdb for me for a while. Will definitely be following #860 for more information.

[hyangah]

@AlbinoGeek Let me clarify - this is a bug affecting only when using 'Run without Debug' (Ctrl+F5). You can still specify ldflags using buildFlags setting for Run (F5). That will ask delve to run your program.

[AlbinoGeek]

The issue boils down to:

• vscode-go provides no mechanism to pass -ldflags "-X main.PROGRAM=\"sc2-rsu\"" to the build.
• Adding this to the buildFlags field of launch.json results in two non-working scenarios described above.
  • (one with F5)
  • (one with Ctrl+F5)

[hyangah]

@AlbinoGeek

"buildFlags": "-ldflags='-X main.PROGRAM=sc2-rsu -X main.VERSION=1.debug'",

(The first one in your example) This form should work with F5. If not, that's a different issue.

If the quotes around sc2-rsu is critical, please try
` "buildFlags": "-ldflags='-X main.PROGRAM="sc2-rsu" -X main.VERSION=1.debug"'

At least, with F5, I hope you can continue debugging your program.

@suzmue FYI here is how delve is processing buildFlags https://github.com/go-delve/delve/blob/f559c3c421dcb0777896114673f2f270a2895290/pkg/gobuild/gobuild.go#L44-L64
And, this is not a regression in v0.19.X. This issue around noDebug mode build flag parsing existed for a while.

[AlbinoGeek]

@hyangah Unfortunately, as I described in my previous reply, it does not work with or without Ctrl.

See the Live Reproduction section of this comment: #1027 (comment)

[hyangah]

@AlbinoGeek That looks like a different issue (sorry I couldn't build your example). Either provide a minimal repro case or, add the following in your launch.json to capture the log and share with us. Thanks!

 "showLog": true,
 "logOutput": "rpc",
 "trace": "verbose"

[hyangah]

Closing in favor of #1111