all, cmd/internal/moddeps: tree is inconsistent state and tests aren't reporting it

[dmitshur]

There are a few mild but unexpected inconsistencies in the tree at tip (commit 15a374d as of this posting):

• cmd uses golang.org/x/sys@v0.0.0-20210511113859-b0526f3d8744 but std selects a different, slightly older version golang.org/x/sys@v0.0.0-20210503173754-0981d6026fa6
• net/http/{h2,socks}_bundle.go aren't in sync with x/net/{http2,internal/socks} packages selected in go.mod

Tests in cmd/internal/moddeps exist to catch this type of skew, yet longtest builders are green and these tests are passing locally:

$ gotip version
go version devel go1.17-15a374d5c Wed May 19 01:09:20 2021 +0000 darwin/amd64
$ gotip test cmd/internal/moddeps
ok  	cmd/internal/moddeps	1.045s

This is due to a recent bug in findGorootModules causing no modules to be found (similar to #46027), and therefore no modules to be tested:

$ gotip test -v cmd/internal/moddeps
=== RUN   TestAllDependencies
--- PASS: TestAllDependencies (0.38s)
=== RUN   TestDependencyVersionsConsistent
--- PASS: TestDependencyVersionsConsistent (0.00s)
PASS
ok  	cmd/internal/moddeps	0.494s

(Note no subtests run.)

I'll send a CL to fix the bug, add a safety check that at very least well-known modules are found, and get the tree into a tidy state again.

CC @golang/release, @bcmills, @findleyr, @FiloSottile.

[gopherbot]

Change https://golang.org/cl/320991 mentions this issue: cmd/internal/moddeps: use filepath.SkipDir only on directories

[FiloSottile]

Sorry, in hindsight I should have added the safety check myself in the first CL.