Re: [PATCH] contrib/persistent-https: update ldflags syntax for Go 1.7+

From: Jeff King <peff@peff.net>
Date: Jul 16, 2016, 05:18 UTC
Message-ID: <20160716051800.GA2845@sigill.intra.peff.net>
In-Reply-To: <CAOiOGAcqsdMD0j_ZUdvvGiA9Bd6bUmfvxziN06Rw81f_pO7cgg@mail.gmail.com>

[+cc Shawn, who participated in the original discussion, as I don't
  think Colby really works on git any more]

On Fri, Jul 15, 2016 at 01:44:14PM -0700, Parker Moore wrote:

Show 29 quoted lines

> From: Parker Moore <parkrmoore@gmail.com>
> 
> This fixes contrib/persistent-https builds for Go v1.7+ and is
> compatible with Go v1.5+.
> 
> Running `make all` in `contrib/persistent-https` results in a failure
> on Go 1.7 and above.
> 
> Specifically, the error is:
> 
>     go build -o git-remote-persistent-https \
>    -ldflags "-X main._BUILD_EMBED_LABEL 1468613136"
>     # _/Users/parkr/github/git/contrib/persistent-https
>     /usr/local/Cellar/go/1.7rc1/libexec/pkg/tool/darwin_amd64/link: -X
> flag requires argument of the form importpath.name=value
>     make: *** [git-remote-persistent-https] Error 2
> 
> This `name=value` syntax for the -X flag was introduced in Go v1.5
> (released Aug 19, 2015):
> 
> - release notes: https://golang.org/doc/go1.5#link
> - commit: https://github.com/golang/go/commit/12795c02f3d6fc54ece09a86e70aaa40a94d5131
> 
> In Go v1.7, support for the old syntax was removed:
> 
> - release notes: https://tip.golang.org/doc/go1.7#compiler
> - commit: https://github.com/golang/go/commit/51b624e6a29b135ce0fadb22b678acf4998ff16f
> 
> This patch includes the `=` to fix builds with Go v1.7+.

With the disclaimer that I have very little experience with Go, this seems like a good, well-explained change. My only question would be whether people still use pre-v1.5 versions of Go, since it sounds like this would adversely affect them if they do. (If it does, it seems the Go people did not give a very good deprecation period for the syntax change, if people are using both the pre-new-syntax and post-old-syntax versions simultaneously). I'm not sure what the alternative is, beyond perhaps checking the version of Go dynamically in the Makefile.

-Peff