mocking dependencies located in a vendor directory

[rgarcia]

If you vendor a dependency into vendor/, what's the best way to generate mocks for it?

If you use mockgen to generate mocks for that specific version of it, e.g. mockgen a/vendor/somedependency, the generated mock has the wrong import: import somedependency "a/vendor/somedependency".

The workaround I'm currently using is making sure the version in $GOPATH/src/a/vendor/somedependency matches the version in $GOPATH/src/somedependency, and then running mockgen somedependency generates the correct code. This is cumbersome!

[dsymonds]

Interesting. I haven't played with GO15VENDOREXPERIMENT yet, so I don't know what's involved.

[dsymonds]

After a quick skim of mockgen (but not actually trying it out in practice), I think it should just work as long as you pass the same import path to mockgen as you write in your app. You should be able to run mockgen somedependency Foo, since mockgen will simply run go build with a generated program using that import path. What fails if you do that?

[dsymonds]

Ah, yes, golang/go#12019 is certainly interesting and might be the cause of the breakage.

[rgarcia]

@dsymonds yeah, in order for it to "just work" you also need to change mockgen to generate the temp program in the current directory. Then the call to go build will correctly import the vendored version. I made this change but then ran into golang/go#12019.

[stevvooe]

I experienced something similar using Go 1.6 with vendored packages. From the error output, it looks like the vendored packages are being ignoring in the exec phase:

$ mockgen -destination mocked.go github.com/vendored/package SomeInterface
prog.go:13:2: cannot find package "github.com/vendored/package" in any of:
    /usr/local/go/src/github.com/vendored/package (from $GOROOT)
    /home/ubuntu/.go_workspace/src/github.com/vendored/package (from $GOPATH)

Basically, $GOPATH is sanitized and we are trying to build against all vendored packages. github.com/vendored/package is in vendor/ but seems to be ignored by mockgen.

I didn't have time to debug the environment further, but I can provide a reproduction if this isn't enough information to track this down.

If this is a different issue, please let me know and I'll file another.

[rgarcia]

@stevvooe that is the same issue that I have experienced--gomock not reading dependencies from the vendor/ directory. I've changed the title of this issue to be more accurate.

[rgarcia]

@stevvooe I've made a PR (#28) that I believe resolves this issue. Feel free to test using that branch.

[stevvooe]

@rgarcia I just gave the fix a try and it works. Thanks for the PR.

[nizsheanez]

guys, can i help somehow with this ticket?

[stevvooe]

@nizsheanez Help get #28 or a similar solution merged.

I am about drop this package as it has been nothing but a headache.

[sputnik13]

This issue has been open for about a year, if there's a PR and it works, why is it still open? Where are the maintainers?

[stevvooe]

@sputnik13 I'd recommend steering clear of this package, if you can. I'd suggest people just do something similar to the technique described in #35 (comment).