cmd/go: treat VCS errors as hard errors in module search

If we're looking for a module for a/b/c/d/e,
we check for a module named a/b/c/d/e,
then a/b/c/d, then a/b/c, then a/b, then a.
If we know the source repo for a/b/c and that
fails, we should report that error instead of
continuing the loop: a/b and a are useless,
and the error from a/b/c contains important
information.

The errors are now a bit more verbose than
I'd like but they will suffice for Go 1.11.

$ go get github.com/bradfitz/private/sonos
go get github.com/bradfitz/private/sonos: git ls-remote -q origin in /Users/rsc/pkg/mod/cache/vcs/61e3c76780847e514802ec6af8f940f641c6017f711444f05c59cb17ac46d456: exit status 128:
	remote: Repository not found.
	fatal: repository 'https://github.com/bradfitz/private/' not found
$ go list launchpad.net/gocheck
can't load package: package launchpad.net/gocheck: unknown import path "launchpad.net/gocheck": bzr branch --use-existing-dir https://launchpad.net/~niemeyer/gocheck/trunk . in /Users/rsc/pkg/mod/cache/vcs/f46ce2ae80d31f9b0a29099baa203e3b6d269dace4e5357a2cf74bd109e13339: exec: "bzr": executable file not found in $PATH
$

Fixes #26885.
Fixes #26982.

Change-Id: I2f9cf1853d2d68af18adad668c80513b6ba220d6
Reviewed-on: https://go-review.googlesource.com/129683
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/cmd/go/internal/modfetch/codehost/vcs.go b/src/cmd/go/internal/modfetch/codehost/vcs.go
index 03def8e0820c6085d4d2617dd95e5883c48a1b42..9e862a0ef8c0d2059d7bce82d02a49a2ee70d26d 100644 (file)
--- a/src/cmd/go/internal/modfetch/codehost/vcs.go
+++ b/src/cmd/go/internal/modfetch/codehost/vcs.go
@@ -22,6 +22,17 @@ import (
        "cmd/go/internal/str"
 )
 
+// A VCSError indicates an error using a version control system.
+// The implication of a VCSError is that we know definitively where
+// to get the code, but we can't access it due to the error.
+// The caller should report this error instead of continuing to probe
+// other possible module paths.
+type VCSError struct {
+       Err error
+}
+
+func (e *VCSError) Error() string { return e.Err.Error() }
+
 func NewRepo(vcs, remote string) (Repo, error) {
        type key struct {
                vcs    string
@@ -33,6 +44,9 @@ func NewRepo(vcs, remote string) (Repo, error) {
        }
        c := vcsRepoCache.Do(key{vcs, remote}, func() interface{} {
                repo, err := newVCSRepo(vcs, remote)
+               if err != nil {
+                       err = &VCSError{err}
+               }
                return cached{repo, err}
        }).(cached)
 

diff --git a/src/cmd/go/internal/modfetch/repo.go b/src/cmd/go/internal/modfetch/repo.go
index 003479461cc795a576d60479f790123baad27551..c8b133574e7a8d862ecaa9fdc29f23cc53526a03 100644 (file)
--- a/src/cmd/go/internal/modfetch/repo.go
+++ b/src/cmd/go/internal/modfetch/repo.go
@@ -237,6 +237,9 @@ func lookup(path string) (r Repo, err error) {
 func lookupCodeRepo(rr *get.RepoRoot) (codehost.Repo, error) {
        code, err := codehost.NewRepo(rr.VCS, rr.Repo)
        if err != nil {
+               if _, ok := err.(*codehost.VCSError); ok {
+                       return nil, err
+               }
                return nil, fmt.Errorf("lookup %s: %v", rr.Root, err)
        }
        return code, nil

diff --git a/src/cmd/go/internal/modload/import.go b/src/cmd/go/internal/modload/import.go
index 3b954f18fecda200698119f35a5c5b00587ae95e..78ae83e4bf3b5b1e2a79f2c76cda8f938e80d2db 100644 (file)
--- a/src/cmd/go/internal/modload/import.go
+++ b/src/cmd/go/internal/modload/import.go
@@ -14,6 +14,7 @@ import (
        "strings"
 
        "cmd/go/internal/cfg"
+       "cmd/go/internal/modfetch/codehost"
        "cmd/go/internal/module"
        "cmd/go/internal/par"
        "cmd/go/internal/search"
@@ -133,6 +134,9 @@ func Import(path string) (m module.Version, dir string, err error) {
 
        m, _, err = QueryPackage(path, "latest", Allowed)
        if err != nil {
+               if _, ok := err.(*codehost.VCSError); ok {
+                       return module.Version{}, "", err
+               }
                return module.Version{}, "", &ImportMissingError{ImportPath: path}
        }
        return m, "", &ImportMissingError{ImportPath: path, Module: m}

diff --git a/src/cmd/go/internal/modload/query.go b/src/cmd/go/internal/modload/query.go
index bd3141865c2bf000b597636378ce205422e21354..3b550f1db7f74d1ee25196c951d12649bf1ef7d5 100644 (file)
--- a/src/cmd/go/internal/modload/query.go
+++ b/src/cmd/go/internal/modload/query.go
@@ -6,6 +6,7 @@ package modload
 
 import (
        "cmd/go/internal/modfetch"
+       "cmd/go/internal/modfetch/codehost"
        "cmd/go/internal/module"
        "cmd/go/internal/semver"
        "fmt"
@@ -223,6 +224,11 @@ func QueryPackage(path, query string, allowed func(module.Version) bool) (module
        for p := path; p != "."; p = pathpkg.Dir(p) {
                info, err := Query(p, query, allowed)
                if err != nil {
+                       if _, ok := err.(*codehost.VCSError); ok {
+                               // A VCSError means we know where to find the code,
+                               // we just can't. Abort search.
+                               return module.Version{}, nil, err
+                       }
                        if finalErr == errMissing {
                                finalErr = err
                        }

diff --git a/src/cmd/go/testdata/script/mod_vcs_missing.txt b/src/cmd/go/testdata/script/mod_vcs_missing.txt
new file mode 100644 (file)
index 0000000..fb146b4
--- /dev/null
+++ b/src/cmd/go/testdata/script/mod_vcs_missing.txt
@@ -0,0 +1,11 @@
+[exec:bzr] skip 'tests NOT having bzr'
+[!net] skip
+
+env GO111MODULE=on
+env GOPROXY=
+
+! go list launchpad.net/gocheck
+stderr '"bzr": executable file not found'
+
+-- go.mod --
+module m