Re: GO111MODULE=on and "go: cannot use modules with build cache disabled"

[Julian Gilbey <julian-pkggo@d-and-j.net>]

On Tue, Feb 26, 2019 at 11:20:00AM +0100, Michael Stapelberg wrote:
> My guess is that you need to set GOCACHE to a temporary directory. This should
> be done within dh-golang itself, so please send a patch.
> I think you’re treading on unchartered territory here — I’m not aware of any
> package within Debian using Go modules yet.

Thanks Michael!

I tried manually creating a temporary directory and setting GOCACHE to
point to it.  That was successful, though it gave the following
output, which is significantly different in format from what I have
seen before with other builds:

[...]
   dh_auto_build -O--buildsystem=golang
go: finding github.com/rsteube/cobra v0.0.1-zsh-completion-custom
go: finding github.com/rivo/tview v0.0.0-20180419193403-f855bee0205c
[...]
go: finding golang.org/x/net v0.0.0-20180724234803-3673e40ba225
warning: ignoring symlink /home/jdg/debian/go-gitlab/build-area/git-lab-0.15.2/obj-x86_64-linux-gnu/src/cloud.google.com
[... many more similar warnings ...]
go: downloading github.com/xanzy/go-gitlab v0.12.3-0.20181228114601-7bc4155e8bf8
go: downloading github.com/rsteube/cobra v0.0.1-zsh-completion-custom
[... lots more downloading lines ...]
warning: ignoring symlink /home/jdg/debian/go-gitlab/build-area/git-lab-0.15.2/obj-x86_64-linux-gnu/src/cloud.google.com
[... many more similar warnings ...]
go: finding github.com/spf13/cobra v0.0.0-20180412120829-615425954c3b
can't load package: package github.com/zaquestion/lab/obj-x86_64-linux-gnu/pkg/mod/github.com/avast/retry-go@v0.0.0-20180319101611-5469272a8171: can only use path@version syntax with 'go get'
[... lots more "can't load package" errors ...]
	cd obj-x86_64-linux-gnu && go install -gcflags=all=\"-trimpath=/home/jdg/debian/go-gitlab/build-area/git-lab-0.15.2/obj-x86_64-linux-gnu/src\" -asmflags=all=\"-trimpath=/home/jdg/debian/go-gitlab/build-area/git-lab-0.15.2/obj-x86_64-linux-gnu/src\" -v -p 4 github.com/zaquestion/lab github.com/zaquestion/lab/cmd github.com/zaquestion/lab/docs github.com/zaquestion/lab/internal/browser github.com/zaquestion/lab/internal/config github.com/zaquestion/lab/internal/copy github.com/zaquestion/lab/internal/git github.com/zaquestion/lab/internal/gitlab
internal/race
errors
[...]

and then it goes on to complete the build with no problems.

Hmm, it does seem as though it is actively downloading packages from
the internet with the settings:

export GO111MODULE := on
export GOCACHE := /tmp/tmp.X9n0iu3c3b

That's not good.  :/

Any ideas?  The current package is at
salsa.debian.org:go-team/packages/git-lab.git
(though it is broken when it downloads packages directly: the patch
update-for-new-tview.patch needs to be removed).  There are also other
issues with this package, but they are unrelated.

Best wishes,

   Julian

> On Tue, Feb 26, 2019 at 11:08 AM Julian Gilbey <julian-pkggo@d-and-j.net> wrote:
> 
>   Hi!
> 
>   I'm trying to build a Go package which requires GO111MODULE=on.  So I
>   set
> 
>   export GO111MODULE := on
> 
>   in the debian/rules Makefile (after reading
>   /usr/share/perl5/Debian/Debhelper/Buildsystem/golang.pm - it wasn't
>   obvious how to set this otherwise).  But now the build bombs out very
>   quickly indeed:
> 
>      [...]
>      dh_auto_build -O--buildsystem=golang
>   go: cannot use modules with build cache disabled
>           cd obj-x86_64-linux-gnu && go install
>   -gcflags=all=\"-trimpath=/home/jdg/debian/go-gitlab/build-area/git-lab-0.15.2/obj-x86_64-linux-gnu/src\"
>   -asmflags=all=\"-trimpath=/home/jdg/debian/go-gitlab/build-area/git-lab-0.15.2/obj-x86_64-linux-gnu/src\"
>   -v -p 4
>   go: cannot use modules with build cache disabled
>   dh_auto_build: cd obj-x86_64-linux-gnu && go install
>   -gcflags=all=\"-trimpath=/home/jdg/debian/go-gitlab/build-area/git-lab-0.15.2/obj-x86_64-linux-gnu/src\"
>   -asmflags=all=\"-trimpath=/home/jdg/debian/go-gitlab/build-area/git-lab-0.15.2/obj-x86_64-linux-gnu/src\"
>   -v -p 4 returned exit code 1
>   make: *** [debian/rules:9: build] Error 1
> 
>   Help?!  How do I use GO111MODULE=on and not have the build crash like
>   this?
> 
>   Thanks,
> 
>      Julian
> 
> --
> Best regards,
> Michael