`--version` only shows VCS information when using `go install`

[wjam]

When using this library to build a CLI tool, any call to --version (either through go run . or by running go build and then on the built binary) returns the default 'no VCS information' message.

Looking at the output of debug.ReadBuildInfo, I can see that the Version field is populated but it is missing any value in the Sum field so this line fails.

fang/fang.go

Line 197 in 055c2e3

if info, ok := debug.ReadBuildInfo(); ok && info.Main.Sum != "" {

From testing, it appears the only way to set this field is to go install the binary. This could be difficult if the VCS repository is private or the code requires some amount of generation before being built.

This limitation seems like it should be documented somewhere. It also seems like there should be a way to just say 'trust the VCS information in the binary'.

[wjam]

Note that go install doesn't provide a way to customise the destination of the binary and tends to not be used building the CLI tool for release. It also tends to not be used when building across OSs.

[caarlos0]

that's to be expected, you can also set your own version mechanism if you want to.

generally, what I do is:

• get version via ldflag
• if not available, try build info
• if not available, use either "dev" or "unknown"

e.g.: https://github.com/goreleaser/goreleaser/blob/627614245a2d0facc053fa8197aa64495bff49f9/main.go#L12-L19

[wjam]

Sorry it has been a while since I got back to this. If it is a requirement to set this flag, then it seems like there's missing documentation showing how to use it? The README.md states that the version will come from the build info but doesn't state that it would only work for go install binaries - i.e. ones that were created using go build which still has build info available.