go/build: import packages in module mode when GO111MODULE is "on"
go/build.Import locates package dirctories using 'go list' when in
module mode (finding, downloading, and extracting modules is
complicated, so go/build does not handle it).
Previously, Import used 'go list' if GO111MODULE was not explicitly
off and a go.mod file was present (plus some other conditions). With
this change, if GO111MODULE is "on", a go.mod file does not need to be
present.
Fixes #34669
Change-Id: I9e56871054d4b07c3fc04b6f14a5c8c8e9f3c333
Reviewed-on: https://go-review.googlesource.com/c/go/+/199818
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
diff --git a/src/go/build/build.go b/src/go/build/build.go
index 526d2fe..deeda35 100644
--- a/src/go/build/build.go
+++ b/src/go/build/build.go
@@ -1008,8 +1008,12 @@
return errNoModules
}
- // If modules are not enabled, then the in-process code works fine and we should keep using it.
- switch os.Getenv("GO111MODULE") {
+ // Predict whether module aware mode is enabled by checking the value of
+ // GO111MODULE and looking for a go.mod file in the source directory or
+ // one of its parents. Running 'go env GOMOD' in the source directory would
+ // give a canonical answer, but we'd prefer not to execute another command.
+ go111Module := os.Getenv("GO111MODULE")
+ switch go111Module {
case "off":
return errNoModules
default: // "", "on", "auto", anything else
@@ -1031,19 +1035,21 @@
}
}
- // Look to see if there is a go.mod.
+ // Unless GO111MODULE=on, look to see if there is a go.mod.
// Since go1.13, it doesn't matter if we're inside GOPATH.
- parent := absSrcDir
- for {
- info, err := os.Stat(filepath.Join(parent, "go.mod"))
- if err == nil && !info.IsDir() {
- break
+ if go111Module != "on" {
+ parent := absSrcDir
+ for {
+ info, err := os.Stat(filepath.Join(parent, "go.mod"))
+ if err == nil && !info.IsDir() {
+ break
+ }
+ d := filepath.Dir(parent)
+ if len(d) >= len(parent) {
+ return errNoModules // reached top of file system, no go.mod
+ }
+ parent = d
}
- d := filepath.Dir(parent)
- if len(d) >= len(parent) {
- return errNoModules // reached top of file system, no go.mod
- }
- parent = d
}
cmd := exec.Command("go", "list", "-e", "-compiler="+ctxt.Compiler, "-tags="+strings.Join(ctxt.BuildTags, ","), "-installsuffix="+ctxt.InstallSuffix, "-f={{.Dir}}\n{{.ImportPath}}\n{{.Root}}\n{{.Goroot}}\n{{if .Error}}{{.Error}}{{end}}\n", "--", path)
diff --git a/src/go/build/build_test.go b/src/go/build/build_test.go
index 47a46f8..7040a1b 100644
--- a/src/go/build/build_test.go
+++ b/src/go/build/build_test.go
@@ -420,6 +420,46 @@
}
}
+// Check that a package is loaded in module mode if GO111MODULE=on, even when
+// no go.mod file is present. It should fail to resolve packages outside std.
+// Verifies golang.org/issue/34669.
+func TestImportPackageOutsideModule(t *testing.T) {
+ testenv.MustHaveGoBuild(t)
+
+ // Disable module fetching for this test so that 'go list' fails quickly
+ // without trying to find the latest version of a module.
+ defer os.Setenv("GOPROXY", os.Getenv("GOPROXY"))
+ os.Setenv("GOPROXY", "off")
+
+ // Create a GOPATH in a temporary directory. We don't use testdata
+ // because it's in GOROOT, which interferes with the module heuristic.
+ gopath, err := ioutil.TempDir("", "gobuild-notmodule")
+ if err != nil {
+ t.Fatal(err)
+ }
+ defer os.RemoveAll(gopath)
+ if err := os.MkdirAll(filepath.Join(gopath, "src/example.com/p"), 0777); err != nil {
+ t.Fatal(err)
+ }
+ if err := ioutil.WriteFile(filepath.Join(gopath, "src/example.com/p/p.go"), []byte("package p"), 0666); err != nil {
+ t.Fatal(err)
+ }
+
+ defer os.Setenv("GO111MODULE", os.Getenv("GO111MODULE"))
+ os.Setenv("GO111MODULE", "on")
+ defer os.Setenv("GOPATH", os.Getenv("GOPATH"))
+ os.Setenv("GOPATH", gopath)
+ ctxt := Default
+ ctxt.GOPATH = gopath
+
+ want := "cannot find module providing package"
+ if _, err := ctxt.Import("example.com/p", gopath, FindOnly); err == nil {
+ t.Fatal("importing package when no go.mod is present succeeded unexpectedly")
+ } else if errStr := err.Error(); !strings.Contains(errStr, want) {
+ t.Fatalf("error when importing package when no go.mod is present: got %q; want %q", errStr, want)
+ }
+}
+
func TestImportDirTarget(t *testing.T) {
testenv.MustHaveGoBuild(t) // really must just have source
ctxt := Default
