cmd/doc: go doc rsc.io/quote/v3 in module mode shows wrong import path

[rsc]

In module mode, in a module with rsc.io/quote/v3 as a dependency:

$ go doc rsc.io/quote/v3
package quote // import "rsc.io/quote"

Package quote collects pithy sayings.

func Concurrency() string
func GlassV3() string
func GoV3() string
func HelloV3() string
func OptV3() string
$ 

Note the import comment on the first line of output.
It should say rsc.io/quote/v3.
I do not know why it says rsc.io/quote instead.

[go101]

It looks the specified import path doesn't work when modules feature is enabled.

[agnivade]

/cc @robpike

[dmitshur]

I'll be able to look into this issue.

[dmitshur]

Actually, I can't reproduce this with Go 1.12.1 nor Go tip (at commit fd270d8):

$ cd $(mktemp -d)
$ go mod init m
go: creating new go.mod: module m
$ go get rsc.io/quote/v3
$ go doc rsc.io/quote/v3
package quote // import "rsc.io/quote/v3"

Package quote collects pithy sayings.

func Concurrency() string
func GlassV3() string
func GoV3() string
func HelloV3() string
func OptV3() string

@rsc What version of Go did you use? Where were the commands you ran before to initialize the main module?

[dmitshur]

There's a chance this is the same issue as #28992 (comment).

[gopherbot]

Timed out in state WaitingForInfo. Closing.

(I am just a bot, though. Please speak up if this is a mistake or you have the requested information.)

[andybons]

@rsc is this still an issue? Do you have updated repro steps? Thanks.

[malisetti]

@dmitshur

$ go doc rsc.io/quote/v3
package quote // import "rsc.io/quote"

Package quote collects pithy sayings.

func HelloV3() string

I ran this on go version go1.12.6 linux/amd64 in a local module aftering go get rsc.io/quote/v3

[dmitshur]

@mseshachalam Did you have a copy of rsc.io/quote repository in your GOPATH/src?

Can you check if commit 3b040b7 fixes it?

[malisetti]

@dmitshur I have a copy of `rsc.io/quote' at $GOPATH/src/rsc.io/quote pointing master branch at rsc/quote@5d9f230
I had to correct a syntax error at v3/quote.go

git diff v3/quote.go
diff --git a/v3/quote.go b/v3/quote.go
index 1f5f3d6..9b6071f 100644
--- a/v3/quote.go
+++ b/v3/quote.go
@@ -10,3 +10,4 @@ import "rsc.io/sampler"
 // Hello returns a greeting.
 func HelloV3() string {
        return sampler.Hello()
+}

I tested this with go 1.12.7 and observed the same behavior. Does this version of go include 3b040b7?

[dmitshur]

Go 1.12.7 does not include it, it's currently only available on the latest master branch. You can use golang.org/dl/gotip to try it.

[malisetti]

Yeah. gotip works as expected.

seshachalamm@IMCHLT047:~/hello$ gotip doc rsc.io/quote/v3
package quote // import "rsc.io/quote/v3"

Package quote collects pithy sayings.

func Concurrency() string
func GlassV3() string
func GoV3() string
func HelloV3() string
func OptV3() string

seshachalamm@IMCHLT047:~/hello$ go doc rsc.io/quote/v3
package quote // import "rsc.io/quote"

Package quote collects pithy sayings.

func HelloV3() string

Could you please explain briefly about the changes in gotip and go 1.12.7 ?
The output is significantly different. I imagine gotip is using the tags of a library and go1.12.6 is using master branch ?

[dmitshur]

Thanks for confirming @mseshachalam.

The change was CL 183991, you can read its commit message for details. It fixed issue #28992, which was that in some conditions, go doc was incorrectly using packages in your GOPATH workspace instead of from the appropriate module.

I imagine gotip is using the tags of a library and go1.12.6 is using master branch ?

Yes, it's now using the rsc.io/quote/v3 module (at some version as determined by your main module), instead of the v3 subdirectory of rsc.io/quote repository in your GOPATH workspace (on master branch).