commit 94c68ad279b3c55957e57efe805c47533e51e9f1
author Russ Cox <rsc@golang.org> Tue Jul 10 13:55:26 2018 -0400
committer Russ Cox <rsc@golang.org> Thu Jul 12 03:18:12 2018 +0000
tree 584704800bc543af666fbc185d128753fbf3e08f
parent a42a7e886866b90f9feaa22e3f1307ce2d051d50

cmd/go/internal/modload: finish Import implementation

modload.Import now means "figure out what this import means in the main module",
including searching for a module to add to go.mod if the import is missing.
(Previously it only did the search.)

Fix Import to handle overlapping module file trees correctly:
the fact that x/y/z is in the build list does not mean it is the
module that must provide x/y/z/v2/w or even x/y/z/w.

The definition of "go get x@v" is now easy to explain: if x is a module path,
go get is talking about that module. Otherwise go get is talking about the
module that provides or would provide x if encountered as an import in the
main module.

Simplify the package load process by using the new Import to eliminate
the separate doMissing parallel pass, as suggested by Bryan in an
earlier code review.

Drop modload.SrcMod in favor of modfetch.SrcMod,
and guard against SrcMod unset (filepath.Join(x, y) treats x="" as like x="."),
which can happen in tests.

Fixes golang/go#24851.
Fixes golang/go#26048.
Fixes golang/go#26250.

Change-Id: I16abfa0c095492fc10ccd75f5857c1c087935867
Reviewed-on: https://go-review.googlesource.com/123095
Reviewed-by: Bryan C. Mills <bcmills@google.com>