How do I find relative imports in my Go source?

I'm trying to use dep in my project and when I attempt to add a dependency:

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dep ensure -add github.com/foo/bar

I get lots of errors similar to:

ensure Solve(): No versions of github.com/foo/bar met constraints:
v1.2.3: Could not introduce github.com/foo/bar@v1.2.3, as its subpackage github.com/foo/bar 
does not contain usable Go code (*build.NoGoError).. (Package is required by (root).)

Apparently such problems are generally caused by a relative import within the project in question.

How can I locate the relative imports in a large project, with vendored dependencies? Could any existing Go tools help me here?

My current solution is to crawl through the output of grep -rn '"\./' --include=\*.go ., but that's slow going.

You can use the go list command to find all imported packages.

go list -f '{{ join .Imports "\n" }}'

Internally, relative imports are converted to an absolute path, and prefixed with _, so this should show any relative imports in any of your packages.

go list -f '{{ join .Imports "\n" }}' ./... | grep '^_'

Relative imports don't work with packages referenced by name, since those must be in the GOPATH anyways. It's likely a package you're not using, or something in _test.go files meant to be run implicitly from within the package directory. You can check the test imports separately, however while they are expanded, they are not cleaned and prefixed with _.

go list -f '{{ join .TestImports "\n" }}' ./... | grep '\./'