Got '*pkgtree.NonCanonicalImportRoot' error when porting to dep

[twang2218]

What version of dep are you using (dep version)?

$ dep version
dep:
 version     : v0.4.1
 build date  : 2018-01-27
 git hash    : 37d9ea0
 go version  : go1.9.3
 go compiler : gc
 platform    : darwin/amd64

What dep command did you run?

$ dep init -v
...
(30)  ? attempt github.com/megamsys/go-radosgw with 1 pkgs; at least 1 versions to try
(30)      try github.com/megamsys/go-radosgw@master
(31)  ✗   github.com/megamsys/go-radosgw at master has problem subpkg(s):
(31)            github.com/megamsys/go-radosgw/api has err (*pkgtree.NonCanonicalImportRoot); required by (root).
(30)    ← no more versions of github.com/megamsys/go-radosgw to try; begin backtrack

...

  ✗ solving failed

Solver wall times by segment:
     b-source-exists:  45.62367537s
         b-list-pkgs: 10.186192761s
              b-gmal:  7.940766056s
  b-deduce-proj-root:  579.123944ms
             satisfy:   18.612194ms
            unselect:   15.306904ms
         select-atom:   14.825777ms
         select-root:    2.995456ms
            new-atom:    1.737909ms
           backtrack:     428.235µs
               other:     202.533µs
     b-list-versions:      19.078µs

  TOTAL: 1m4.383886217s

init failed: unable to solve the dependency graph: Solving failure: No versions of github.com/megamsys/go-radosgw met constraints:
        master: Could not introduce github.com/megamsys/go-radosgw@master, as its subpackage github.com/megamsys/go-radosgw/api does not contain usable Go code (*pkgtree.NonCanonicalImportRoot).. (Package is required by (root).)

After I examine the package github.com/megamsys/go-radosgw/api, I found one potential reason caused this error, https://github.com/megamsys/go-radosgw/blob/master/api/helpers_test.go#L3:

package radosAPI
/*
import (
	"os"
	"testing"
	"time"
	. "github.com/smartystreets/goconvey/convey"
)

...

And then I checked the gps/pkgtree/pkgtree.go's findImportComment() function, I think it might be a bug:

https://github.com/golang/dep/blob/master/gps/pkgtree/pkgtree.go#L344-L362

	case bytes.HasPrefix(text, slashStar):
		text = text[2:]
		end := bytes.Index(text, starSlash)
		if end < 0 {
			// malformed comment
			return ""
		}
		text = text[:end]
		if bytes.IndexByte(text, '\n') > 0 {
			// multiline comment, can't be an import comment
			return ""
		}
	}
	text = bytes.TrimSpace(text)
	if !bytes.HasPrefix(text, importKwd) {
		return ""
	}
	quotedPath := bytes.TrimSpace(text[len(importKwd):])
	return string(bytes.Trim(quotedPath, `"`))

I think:

		if bytes.IndexByte(text, '\n') > 0 {

should be

		if bytes.IndexByte(text, '\n') >= 0 {

[twang2218]

I compiled the dep using master branch, and added println() to print the Error details, and here is what I found:

import root "github.com/megamsys/go-radosgw" is not a prefix for the package's declared canonical path "(\n\t\"os\"\n\t\"testing\"\n\t\"time\"\n\n\t. \"github.com/smartystreets/goconvey/convey\"\n)\n\nfunc TestNewAPI(t *testing.T) {\n\tConvey(\"Testing New API\", t, func() {\n\t\tapi := New(os.Getenv(\"RADOSGW_API\"), os.Getenv(\"RADOSGW_ACCESS\"), os.Getenv(\"RADOSGW_SECRET\"))\n\n\t\tSo(api, ShouldNotBeNil)\n\t})\n}\n\nfunc TestNewAPIWithPrefix(t *testing.T) ...

I think it clearly shows the comments have become the canonical path.

[twang2218]

Created a PR #1743 to fix this issue.

[twang2218]

Found a workaround for this issue.

Replace:

/*
import (
    "fmt"
)
...
*/

with

/**
import (
    "fmt"
)
...
*/

Use the double star, /**, then dep will not treat the following comments as the import path.