gomock mockgen : unknown embedded interface

Issue

mockgen -source=./driver/rocket_driver.go -destination ./driver/rocket_driver_mock.go -package driver
2022/06/01 21:39:44 Loading input failed: ./driver/rocket_driver.go:6:2: unknown embedded interface INavigatorDriver
make: *** [mockgen_rocket_driver] Error 1

https://github.com/golang/mock/issues/178

Here are my test files:

github.com/anyuser/test/test1.go:

package test

type A interface {
    Method1()
}

github.com/anyuser/test/test2.go:

package test

type B interface {
    A
}

Here's generation:

mockgen -source test2.go -destination test2_mocks.go -package test -aux_files test=test1.go

Error result:

Loading input failed: test2.go:4:2: unknown embedded interface A

Embedded Interfaces in aux_files

Embedded interfaces in aux_files generate unknown embedded interface XXX errors. See below for example of the problem:

// source
import (
    alias "some.org/package/imported"
)

type Source interface {
    alias.Foreign
}
// some.org/package/imported
type Foreign interface {
    Embedded
}

type Embedded interface {}

Attempting to generate a mock will result in an unknown embedded interface Embedded. The issue is that the fileParser stores auxInterfaces underneath the package name explicitly specified in the aux_files flag.

In the parseInterface method, there is an incorrect assumption about an embedded interface always being in the source file.

case *ast.Ident:
        // Embedded interface in this package.
        ei := p.auxInterfaces[""][v.String()]
        if ei == nil {
                return nil, p.errorf(v.Pos(), "unknown embedded interface %s", v.String())
        }

https://pkg.go.dev/github.com/golang/mock/mockgen/internal/tests/aux_imports_embedded_interface#section-readme

Solution

Don't put the rocket_driver.go With other dependent interface Put it in the same package below ( mockgen Default assumptions for ? ) .

mockgen -source=./rocket/rocket_driver.go 
-destination ./rocket/rocket_driver_mock.go 
-package rocket 
-aux_files rocket=service/basic_info_service.go,rocket=driver/navigator_driver.go

type IRocketFetcher interface {
    service.BasicInfoService
    driver.INavigatorDriver
}

type RocketFetcher struct {
}

func NewRocketFetcher() *RocketFetcher { return &RocketFetcher{} }

Source code project directory :

.
├── Makefile
├── README.md
├── alpha
│   ├── cql.go
│   ├── cql_compiler.go
│   ├── cql_compiler_test.go
│   └── cql_util.go
├── component
│   ├── component.go
│   └── component_test.go
├── constant
│   └── sql_key.go
├── datasource
│   └── data_source.go
├── driver
│   ├── navigator_driver.go
│   ├── navigator_driver_mock.go
│   ├── navigator_driver_mock_data.go
│   ├── sqlite_driver.go
│   └── sqlite_driver_test.go
├── go.mod
├── go.sum
├── lang
│   └── lang.go
├── onetable
│   ├── one_table.go
│   └── one_table_test.go
├── rocket
│   ├── basic_common.go
│   ├── basic_common_test.go
│   ├── index_common.go
│   ├── rocket_fetcher.go
│   ├── rocket_fetcher_mock.go
│   ├── rocket_fetcher_test.go
│   ├── rsd.go
│   └── rsd_test.go
├── service
│   ├── basic_info_service.go
│   ├── basic_info_service_mock.go
│   └── basic_info_service_test.go
├── stream
│   ├── parallel.go
│   ├── parallel_test.go
│   ├── ring.go
│   ├── ring_test.go
│   ├── stream.go
│   └── stream_test.go
├── stringx
│   ├── node.go
│   ├── node_fuzz_test.go
│   ├── node_test.go
│   ├── random.go
│   ├── random_test.go
│   ├── replacer.go
│   ├── replacer_fuzz_test.go
│   ├── replacer_test.go
│   ├── strings.go
│   ├── strings_test.go
│   ├── trie.go
│   └── trie_test.go
├── test_report.html
├── threading
│   ├── coroutinegroup.go
│   ├── coroutinegroup_test.go
│   ├── recover.go
│   ├── recover_test.go
│   ├── routines.go
│   ├── routines_test.go
│   ├── taskrunner.go
│   ├── taskrunner_test.go
│   ├── workergroup.go
│   └── workergroup_test.go
├── udfs
│   ├── indexation_convert.go
│   └── udf.go
└── utils
    ├── basic
    │   ├── basic_common.go
    │   ├── basic_constu.go
    │   ├── basic_util.go
    │   └── hotsoon_item_pack.go
    ├── chart
    │   └── chart_common.go
    ├── co
    │   ├── concurrent.go
    │   └── concurrent_test.go
    ├── convert.go
    ├── copy
    │   ├── copier.go
    │   └── errors.go
    ├── dimu
    │   └── dimu.go
    ├── indexu
    │   ├── constu.go
    │   ├── indexu.go
    │   └── parse_request.go
    ├── modelu
    │   ├── error.go
    │   └── model.go
    ├── numberu
    │   └── numberu.go
    ├── rocket_constu
    │   └── constu.go
    ├── slicesu
    │   └── slicesu.go
    ├── stringu
    │   └── stringu.go
    ├── structu
    │   └── structu.go
    └── timeu
        ├── date_type.go
        ├── timeu.go
        └── timeu_test.go

27 directories, 86 files

mockgen Instruction parameter description

-source : 
A file containing interfaces to be mocked.
 
-destination :
A file to which to write the resulting source code. 
If you don't set this, the code is printed to standard output.

-package :
The package to use for the resulting mock class source code. 
If you don't set this, the package name is mock_ concatenated with the package of the input file.
 
-imports :
A list of explicit imports that should be used in the resulting source code,
 specified as a comma-separated list of elements of the form `foo=bar/baz` , 
where `bar/baz`  is the package being imported ,  
and `foo`  is the identifier to use for the package in the generated source code.
 
-aux_files: 
A list of additional files that should be consulted to resolve 
e.g. embedded interfaces defined in a different file. 

This is specified as a comma-separated list of elements of the form foo=bar/baz.go, 
where bar/baz.go is the source file 
and foo is the package name of that file used by the -source file.
 
-build_flags: 
(reflect mode only) Flags passed verbatim to go build.
 
-mock_names: 
A list of custom names for generated mocks. This is specified as a comma-separated list of elements of the form Repository=MockSensorRepository,Endpoint=MockSensorEndpoint, where Repository is the interface name and MockSensorRepository is the desired mock name (mock factory method and mock recorder will be named after the mock). If one of the interfaces has no custom name specified, then default naming convention will be used.
 
 
-copyright_file: Copyright file used to add copyright header to the resulting source code.

Go Interface composition in language ( Interface contains interface )

stay Go In language , Can be in the interface A Combine one or more other interfaces in ( Such as interface B、C), This approach is equivalent to the interface A Add interface to B、C The method declared in .

// Other interfaces can be combined in the interface , This method is equivalent to adding methods of other interfaces to the interface 
type Reader interface {
    read()
}
type Writer interface {
    write()
}

// Define the implementation classes of the above two interfaces 
type MyReadWrite struct{}

func (mrw *MyReadWrite) read() {
    fmt.Println("MyReadWrite...read")
}

func (mrw *MyReadWrite) write() {
    fmt.Println("MyReadWrite...write")
}

// Define an interface , The above two interfaces are combined 
type ReadWriter interface {
    Reader
    Writer
}

// The above interface is equivalent to ：
type ReadWriterV2 interface {
    read()
    write()
}

//ReadWriter and ReadWriterV2 The two interfaces are equivalent , So we can assign values to each other 
func interfaceTest0104() {
    mrw := &MyReadWrite{}
    //mrw Object implementation read() Methods and write() Method , So it can be assigned to ReadWriter and ReadWriterV2
    var rw1 ReadWriter = mrw
    rw1.read()
    rw1.write()

    fmt.Println("------")
    var rw2 ReadWriterV2 = mrw
    rw2.read()
    rw2.write()

    // meanwhile ,ReadWriter and ReadWriterV2 Two interface objects can assign values to each other 
    rw1 = rw2
    rw2 = rw1
}

Reference material

https://stackoverflow.com/questions/55999405/how-can-i-mock-specific-embedded-method-inside-interface

https://pkg.go.dev/github.com/golang/mock/gomock

https://github.com/golang/mock#running-mockgen