go mod: something goes wrong with private git projects when imports with the suffix .git

[anotherGoogleFan]

What version of Go are you using (go version)?

$ go version
go version go1.13.1 windows/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
set GO111MODULE=
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\huangtao\AppData\Local\go-build
set GOENV=C:\Users\huangtao\AppData\Roaming\go\env
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GONOPROXY=*.example.net
set GONOSUMDB=*.example.net
set GOOS=windows
set GOPATH=E:\GoProjects
set GOPRIVATE=*.example.net
set GOPROXY=direct,https://goproxy.cn,https://goproxy.io,https://proxy.golang.org
set GOROOT=c:\go
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=c:\go\pkg\tool\windows_amd64
set GCCGO=gccgo
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\Users\huangtao\AppData\Local\Temp\go-build102197674=/tmp/go-build -gno-record-gcc-switches

What did you do?

There're 2 private git projects, A and B. Both use go mod.
Project A's go mod, for example, like this:

module git.example.net/go/a

go 1.13

xxxxxxx(replace and requires here)

In project A, I import project B.

import "git.example.net/go/b.git/xxx"

Project B's go mod, for example, like this:

module git.example.net/go/b

go 1.13

xxxxxxx(replace and requires here)

And I build the project A.

What did you expect to see?

build pass

What did you see instead?

go: git.example.net/go/a/repository imports
        git.example.net/go/b.git/xxx: git.example.net/go/[email protected]: parsing go.mod:
        module declares its path as: git.example.net/go/b
                but was required as: git.example.net/go/b.git

[bcmills]

The error message here is telling you exactly what is wrong: B's go.mod file declares its import path to be git.example.net/go/b, but you are instead importing it as git.example.net/go/b.git.

The path in the module directive must match the path used in import statements. The .git suffix is part of the import path, not just an annotation.

[anotherGoogleFan]

@bcmills Thanks for response.
But may I ask what should I do in this situation if I need to use the project git.example.net/go/b without changing it? If I import without .git suffix, I can only get another error:

git.example.net/a/repository imports
        git.example.net/go/b: cannot find module providing package git.example.net/go/b

[bcmills]

what should I do in this situation if I need to use the project git.example.net/go/b without changing it?

Your options include:

1. Set up an HTTPS server on git.example.net serving <meta> tags as described in https://golang.org/cmd/go/#hdr-Remote_import_paths.

   • This is the most robust solution, but requires that you (or someone) configure a server on that host.
   • This approach should make import "git.example.net/go/b/xxx" work without modifying the code.

2. Change B's go.mod file from

   module git.example.net/go/b
   

   to

   module git.example.net/go/b.git
   

   and update theimport statements within A and B accordingly.

   • This should make import "git.example.net/go/b.git/xxx" work without modifying the server.

3. Add a replace directive to A's go.mod file:

   replace git.example.net/go/b v0.0.0-20191009034226-6b9a95059d66 => git.example.net/go/b.git v0.0.0-20191009034226-6b9a95059d66
   

   • This would not fix any downstream consumers of A, who would need to copy that replacement into their own go.mod file.

[anotherGoogleFan]

@bcmills
Thanks for response.
I tried the 3rd option you supported, and when I add the replace

replace git.example.net/go/b.git  => git.example.net/go/b latest

I got another error

git.example.net/go/a/repository imports
        git.example.net/go/b/xxx: unrecognized import path "git.example.net/go/b" (https fetch: Get https://git.example.net/go/b?go-get=1: x509: certificate signed by unknown authority)

But when I tried

go get -u -v git.example.net/go/b

and it goes well. It seems something strange happened here.

[bcmills]

when I add the replace

You'll want to replace b with b.git, not the other way around.

I don't know why go get -u -v git.example.net/go/b would behave differently.