v0.5.0 mock generated do not compile due to name clash #218
Description
Hello. I tried to use this project in v0.5.0 from v0.4.0, and this produced code that doesn't compile anymore. I produced a smaller example here than my real project. I can push a private simplified repo if needs be for full repro.
Actual behavior A clear and concise description of what the bug is.
generating mocks finishes without error, and produces code that does not compile. Instead, when running tests, I'll get a packagename.WhateverExported is not a type
Expected behavior A clear and concise description of what you expected to happen.
generating mocks finishes without error, and produces code that compiles
To Reproduce Steps to reproduce the behavior
$ tree
.
├── go.mod
├── go.sum
├── main.go
├── p2
│ ├── mocks
│ │ └── mocks.go
│ └── thing.go
├── packagename
│ └── foo.go
├── tools.go
└── vendor
snip
├── go.uber.org
│ └── mock
│ ├── AUTHORS
│ ├── LICENSE
│ └── mockgen
│ ├── deprecated.go
│ ├── generic.go
│ ├── gob.go
│ ├── mockgen.go
│ ├── model
│ │ └── model.go
│ ├── package_mode.go
│ ├── parse.go
│ └── version.go
└── modules.txt
45 directories, 113 files
// go.mod
module mockgenImportProblem
go 1.23.0
require go.uber.org/mock v0.5.0
require (
golang.org/x/mod v0.18.0 // indirect
golang.org/x/sync v0.7.0 // indirect
golang.org/x/tools v0.22.0 // indirect
)
// packagename/foo.go
package packagename
type WhateverExported struct {
}
// p2/thing.go
//go:generate mockgen -destination=mocks/mocks.go -package=mocks mockgenImportProblem/p2 Mything
package p2
import (
"mockgenImportProblem/packagename"
)
type Mything interface {
// issue here, is that the variable has the same name as an imported package.
DoThat(packagename int) packagename.WhateverExported
}With v0.4.0, we get
// DoThat mocks base method.
func (m *MockMything) DoThat(arg0 int) packagename.WhateverExported {
m.ctrl.T.Helper()
ret := m.ctrl.Call(m, "DoThat", arg0)
ret0, _ := ret[0].(packagename.WhateverExported)
return ret0
}with v0.5.0 we have
// DoThat mocks base method.
func (m *MockMything) DoThat(packagename int) packagename.WhateverExported {
m.ctrl.T.Helper()
ret := m.ctrl.Call(m, "DoThat", packagename)
ret0, _ := ret[0].(packagename.WhateverExported) // there is the problem. because the 'packagename' refers to the integer passed as parameter, and not to the import. This was not an issue in v0.4 because few packages are named (arg0, arg1, ...) but the potential for conflict between variable names and import packages is more important in v0.5 since both are provided by the end developer.
return ret0
}The solution for my work project is to wait for a fix upstream. A workaround is to rename the variable DoThat(packagename int) packagename.WhateverExported => DoThat(packagename2 int) packagename.WhateverExported, but it's annoying.
A full fix will be to introduce some deterministic aliases to the package imports, making sure that the name is not reused by a parameter name.
Additional Information
- gomock mode (reflect or source): SOURCE, with 0.4 and 0.5
- golang version: 1.23
Triage Notes for the Maintainers
Thanks for maintaining this project.