IntelliJ has “show implementations” which will do what you want.
> On Dec 7, 2018, at 11:13 AM, Burak Serdar <bser...@ieee.org> wrote:
>
> On Fri, Dec 7, 2018 at 9:53 AM David Wahlstedt
> <david.wahlstedt....@gmail.com> wrote:
>>
>> Hi,
>> I am still quite inexperienced in go programming, and I find it quite
>> frustrating, sometimes, to find what will actually be executed by a call to
>> an interface method found in some arbitrary code.
>> Here I have traced the process of finding the definition of "conn.Close()"
>> an instance of an interface method call. This is what I would like to have
>> automatized by godef, for instance.
>> Is there anything like that out there that does it with one command / key
>> stroke, etc, automagically ?
>
> That is not possible in general. This is not unique to go either.
> Consider a function like:
>
> type Shape interface {
> Draw()
> }
>
> func draw(shapes []Shape) {
> for _,x:=range shapes {
> x.Draw()
> }
> }
>
>
> Each element of 'shapes' can be a different type, with a different
> Draw() implementation.
>
> What I do in these situations is to either backtrack calls as you did,
> or simply use grep, and find a list of candidate implementations, and
> work from there.
>
> This is somewhat easier with languages like Java because you can look
> for classes implementing that interface, but then you still have to
> work with a list of candidates.
>
>
>
>
>> Godef and go-guru does not, as far as I know.
>>
>> BR,
>> David
>>
>> Here follows some anonymized code:
>> (please forgive me if I've made some errors, I hope you get the idea anyway)
>>
>> In the file file1.go:1234 in the library lib1, I found a call:
>> : _ = conn.Close()
>> How do i figure out what happens when this line is executed?
>> Here is a list of steps to find it "mechanically", so to say:
>> 1. file1.go:1234
>> : func returnConn(conn lib2.Conn) {
>> : _ = conn.Close()
>> : }
>>
>> Using godef-jump on the Close() will just give me the interface
>> declaration. I can use go-guru-implements, and get a list of
>> possible implementations of Close, but how do I know which one will
>> actually be used? So, let's figure out the actual type of conn.
>> I use go-guru-referrers on returnConn, and choose one of the hits,
>> which is file1.go:206
>>
>> 2. file1.go:206
>> : func (r *Record) Release(foo bar.T1) error {
>> : ...
>> : var conn lib2.Conn
>> : if conn, err = r.foo.getConn(baz); err != nil {
>> : return err
>> : }
>> : defer returnConn(conn)
>> conn gets its value from getConn, so I end up in file1.go:1074
>>
>> 3. file1.go:1074
>> : func (foo *FOO) getConn(mu T2) (lib2.Conn, error) {
>> : ...
>> : conn := foo.connBax.Get()
>> : ...
>> : return conn, nil
>> conn gets its value from Get(), so I go to file3.go:178
>>
>> 4. file3.go:178
>> : func (p *Bax) Get() Conn {
>> : ...
>> : return &xooConn{x: p, xc: xc}
>> I find the return value and go to its definition in file3.go:371
>>
>> 5. file3.go:371
>> : type xooConn struct {
>> : x *Bax
>> : xc *baxConn
>> : s T3
>> : }
>> Aaah! This is the type of conn at file1.go:1234!
>>
>> 6. file1.go:1234
>> : _ = conn.Close()
>> Now I can follow the "definition" of Close() using godef-jump, and
>> end up in file1.go:30:
>>
>> 7. file1.go:30
>> : type Conn interface {
>> : Close() error
>>
>> I use go-guru-implements to see a list of possible implementations:
>> : PATH1/lib2/dir1/file1.go:30.2-30.6: abstract method func
>> (ConnWithTimeout).Close() error
>> : PATH1/lib2/dir1/file3.go:394.23-394.27: is implemented by method
>> (*xooConn).Close
>> : PATH1/lib2/dir1/conn.go:304.16-304.20: is implemented by method
>> (*conn).Close
>> : PATH1/lib2/dir1/boo.go:12.3-45.6: is implemented by method
>> (*booingConn).Close
>> : PATH1/lib2/dir1/file3.go:510.21-510.25: is implemented by method
>> (errorConn).Close
>> : PATH1/lib2/dir1/file1.go:30.2-30.6: implements method (Conn).Close
>> : PATH2/bah.go:78.9-101.2: implements method (bah.Closer).Close
>> Now, since I know the type is *xooConn, I can jump to the right hit,
>> and go to file3.go:394.
>> 8. file3.go:394
>> : func (ac *xooConn) Close() error {
>> : pc := ac.pc
>> : ...
>> : return nil
>> Yes, here it is, at step 8!!!!
>>
>> --
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