cmd/go: only generate a go.mod file during 'go mod init'
In the general case, we do not know the correct module path for a new
module unless we have checked its VCS tags for a major version. If we
do not know the correct path, then we should not synthesize a go.mod
file automatically from it.
On the other hand, we don't want to run VCS commands in the working
directory without an explicit request by the user to do so: 'go mod
init' can reasonably invoke a VCS command, but 'go build' should not.
Therefore, we should only create a go.mod file during 'go mod init'.
This change removes the previous behavior of synthesizing a file
automatically, and instead suggests a command that the user can opt to
run explicitly.
Updates #29433
Updates #27009
Updates #30228
Change-Id: I8c4554969db17156e97428df220b129a4d361040
Reviewed-on: https://go-review.googlesource.com/c/162699
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
diff --git a/src/cmd/go/internal/modload/init.go b/src/cmd/go/internal/modload/init.go
index 22d14cc..a0514d4 100644
--- a/src/cmd/go/internal/modload/init.go
+++ b/src/cmd/go/internal/modload/init.go
@@ -154,7 +154,7 @@
die() // Don't init a module that we're just going to ignore.
}
// No automatic enabling in GOPATH.
- if root, _ := FindModuleRoot(cwd, "", false); root != "" {
+ if root := findModuleRoot(cwd); root != "" {
cfg.GoModInGOPATH = filepath.Join(root, "go.mod")
}
return
@@ -164,7 +164,7 @@
// Running 'go mod init': go.mod will be created in current directory.
modRoot = cwd
} else {
- modRoot, _ = FindModuleRoot(cwd, "", MustUseModules)
+ modRoot = findModuleRoot(cwd)
if modRoot == "" {
if !MustUseModules {
// GO111MODULE is 'auto' (or unset), and we can't find a module root.
@@ -302,6 +302,19 @@
if inGOPATH && !MustUseModules {
base.Fatalf("go: modules disabled inside GOPATH/src by GO111MODULE=auto; see 'go help modules'")
}
+ if cwd != "" {
+ if dir, name := findAltConfig(cwd); dir != "" {
+ rel, err := filepath.Rel(cwd, dir)
+ if err != nil {
+ rel = dir
+ }
+ cdCmd := ""
+ if rel != "." {
+ cdCmd = fmt.Sprintf("cd %s && ", rel)
+ }
+ base.Fatalf("go: cannot find main module, but found %s in %s\n\tto create a module there, run:\n\t%sgo mod init", name, dir, cdCmd)
+ }
+ }
base.Fatalf("go: cannot find main module; see 'go help modules'")
}
@@ -330,12 +343,6 @@
gomod := filepath.Join(modRoot, "go.mod")
data, err := ioutil.ReadFile(gomod)
if err != nil {
- if os.IsNotExist(err) {
- legacyModInit()
- modFileToBuildList()
- WriteGoMod()
- return
- }
base.Fatalf("go: %v", err)
}
@@ -349,7 +356,7 @@
if len(f.Syntax.Stmt) == 0 || f.Module == nil {
// Empty mod file. Must add module path.
- path, err := FindModulePath(modRoot)
+ path, err := findModulePath(modRoot)
if err != nil {
base.Fatalf("go: %v", err)
}
@@ -387,7 +394,7 @@
func legacyModInit() {
if modFile == nil {
- path, err := FindModulePath(modRoot)
+ path, err := findModulePath(modRoot)
if err != nil {
base.Fatalf("go: %v", err)
}
@@ -454,19 +461,13 @@
".git/config",
}
-// Exported only for testing.
-func FindModuleRoot(dir, limit string, legacyConfigOK bool) (root, file string) {
+func findModuleRoot(dir string) (root string) {
dir = filepath.Clean(dir)
- dir1 := dir
- limit = filepath.Clean(limit)
// Look for enclosing go.mod.
for {
if fi, err := os.Stat(filepath.Join(dir, "go.mod")); err == nil && !fi.IsDir() {
- return dir, "go.mod"
- }
- if dir == limit {
- break
+ return dir
}
d := filepath.Dir(dir)
if d == dir {
@@ -474,37 +475,41 @@
}
dir = d
}
+ return ""
+}
- // Failing that, look for enclosing alternate version config.
- if legacyConfigOK {
- dir = dir1
- for {
- for _, name := range altConfigs {
- if fi, err := os.Stat(filepath.Join(dir, name)); err == nil && !fi.IsDir() {
- return dir, name
+func findAltConfig(dir string) (root, name string) {
+ dir = filepath.Clean(dir)
+ for {
+ for _, name := range altConfigs {
+ if fi, err := os.Stat(filepath.Join(dir, name)); err == nil && !fi.IsDir() {
+ if rel := search.InDir(dir, cfg.BuildContext.GOROOT); rel == "." {
+ // Don't suggest creating a module from $GOROOT/.git/config.
+ return "", ""
}
+ return dir, name
}
- if dir == limit {
- break
- }
- d := filepath.Dir(dir)
- if d == dir {
- break
- }
- dir = d
}
+ d := filepath.Dir(dir)
+ if d == dir {
+ break
+ }
+ dir = d
}
-
return "", ""
}
-// Exported only for testing.
-func FindModulePath(dir string) (string, error) {
+func findModulePath(dir string) (string, error) {
if CmdModModule != "" {
// Running go mod init x/y/z; return x/y/z.
return CmdModModule, nil
}
+ // TODO(bcmills): once we have located a plausible module path, we should
+ // query version control (if available) to verify that it matches the major
+ // version of the most recent tag.
+ // See https://golang.org/issue/29433 and https://golang.org/issue/27009.
+
// Cast about for import comments,
// first in top-level directory, then in subdirectories.
list, _ := ioutil.ReadDir(dir)
diff --git a/src/cmd/go/internal/modload/init_test.go b/src/cmd/go/internal/modload/init_test.go
deleted file mode 100644
index 2df9d8a..0000000
--- a/src/cmd/go/internal/modload/init_test.go
+++ /dev/null
@@ -1,42 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package modload
-
-import (
- "io/ioutil"
- "os"
- "path/filepath"
- "testing"
-)
-
-func TestFindModuleRootIgnoreDir(t *testing.T) {
- // In Plan 9, directories are automatically created in /n.
- // For example, /n/go.mod always exist, but it's a directory.
- // Test that we ignore directories when trying to find go.mod and other config files.
-
- dir, err := ioutil.TempDir("", "gotest")
- if err != nil {
- t.Fatalf("failed to create temporary directory: %v", err)
- }
- defer os.RemoveAll(dir)
- if err := os.Mkdir(filepath.Join(dir, "go.mod"), os.ModeDir|0755); err != nil {
- t.Fatalf("Mkdir failed: %v", err)
- }
- for _, name := range altConfigs {
- if err := os.MkdirAll(filepath.Join(dir, name), os.ModeDir|0755); err != nil {
- t.Fatalf("MkdirAll failed: %v", err)
- }
- }
- p := filepath.Join(dir, "example")
- if err := os.Mkdir(p, os.ModeDir|0755); err != nil {
- t.Fatalf("Mkdir failed: %v", err)
- }
- if root, _ := FindModuleRoot(p, "", false); root != "" {
- t.Errorf("FindModuleRoot(%q, \"\", false): %q, want empty string", p, root)
- }
- if root, _ := FindModuleRoot(p, "", true); root != "" {
- t.Errorf("FindModuleRoot(%q, \"\", true): %q, want empty string", p, root)
- }
-}
diff --git a/src/cmd/go/internal/modload/load.go b/src/cmd/go/internal/modload/load.go
index 5bb943d..6d6c037 100644
--- a/src/cmd/go/internal/modload/load.go
+++ b/src/cmd/go/internal/modload/load.go
@@ -111,7 +111,7 @@
} else {
pkg = Target.Path + suffix
}
- } else if sub := search.InDir(dir, cfg.GOROOTsrc); sub != "" && !strings.Contains(sub, "@") {
+ } else if sub := search.InDir(dir, cfg.GOROOTsrc); sub != "" && sub != "." && !strings.Contains(sub, "@") {
pkg = filepath.ToSlash(sub)
} else if path := pathInModuleCache(dir); path != "" {
pkg = path
diff --git a/src/cmd/go/testdata/script/mod_convert_dep.txt b/src/cmd/go/testdata/script/mod_convert_dep.txt
index cc1083b..267c90e 100644
--- a/src/cmd/go/testdata/script/mod_convert_dep.txt
+++ b/src/cmd/go/testdata/script/mod_convert_dep.txt
@@ -1,9 +1,31 @@
env GO111MODULE=on
+# We should not create a go.mod file unless the user ran 'go mod init' explicitly.
+# However, we should suggest 'go mod init' if we can find an alternate config file.
cd $WORK/test/x
+! go list .
+stderr 'found Gopkg.lock in .*[/\\]test'
+stderr '\s*cd \.\. && go mod init'
+
+# The command we suggested should succeed.
+cd ..
+go mod init
go list -m all
stdout '^m$'
+# In Plan 9, directories are automatically created in /n.
+# For example, /n/Gopkg.lock always exists, but it's a directory.
+# Test that we ignore directories when trying to find alternate config files.
+cd $WORK/gopkgdir/x
+! go list .
+stderr 'cannot find main module'
+! stderr 'Gopkg.lock'
+! stderr 'go mod init'
+
-- $WORK/test/Gopkg.lock --
-- $WORK/test/x/x.go --
package x // import "m/x"
+-- $WORK/gopkgdir/Gopkg.lock/README.txt --
+../Gopkg.lock is a directory, not a file.
+-- $WORK/gopkgdir/x/x.go --
+package x // import "m/x"
diff --git a/src/cmd/go/testdata/script/mod_convert_git.txt b/src/cmd/go/testdata/script/mod_convert_git.txt
index 5ef534a..ece505a 100644
--- a/src/cmd/go/testdata/script/mod_convert_git.txt
+++ b/src/cmd/go/testdata/script/mod_convert_git.txt
@@ -1,10 +1,23 @@
env GO111MODULE=on
-# detect root of module tree as root of enclosing git repo
+# We should not create a go.mod file unless the user ran 'go mod init' explicitly.
+# However, we should suggest 'go mod init' if we can find an alternate config file.
cd $WORK/test/x
+! go list .
+stderr 'found .git/config in .*[/\\]test'
+stderr '\s*cd \.\. && go mod init'
+
+# The command we suggested should succeed.
+cd ..
+go mod init
go list -m all
stdout '^m$'
+# We should not suggest creating a go.mod file in $GOROOT, even though there may be a .git/config there.
+cd $GOROOT
+! go list .
+! stderr 'go mod init'
+
-- $WORK/test/.git/config --
-- $WORK/test/x/x.go --
package x // import "m/x"
diff --git a/src/cmd/go/testdata/script/mod_convert_glide.txt b/src/cmd/go/testdata/script/mod_convert_glide.txt
index 50460bb..9f1fff5 100644
--- a/src/cmd/go/testdata/script/mod_convert_glide.txt
+++ b/src/cmd/go/testdata/script/mod_convert_glide.txt
@@ -1,6 +1,15 @@
env GO111MODULE=on
+# We should not create a go.mod file unless the user ran 'go mod init' explicitly.
+# However, we should suggest 'go mod init' if we can find an alternate config file.
cd $WORK/test/x
+! go list .
+stderr 'found glide.lock in .*[/\\]test'
+stderr '\s*cd \.\. && go mod init'
+
+# The command we suggested should succeed.
+cd ..
+go mod init
go list -m all
stdout '^m$'
diff --git a/src/cmd/go/testdata/script/mod_convert_glockfile.txt b/src/cmd/go/testdata/script/mod_convert_glockfile.txt
index 4d9aaff..6aa0794 100644
--- a/src/cmd/go/testdata/script/mod_convert_glockfile.txt
+++ b/src/cmd/go/testdata/script/mod_convert_glockfile.txt
@@ -1,6 +1,15 @@
env GO111MODULE=on
+# We should not create a go.mod file unless the user ran 'go mod init' explicitly.
+# However, we should suggest 'go mod init' if we can find an alternate config file.
cd $WORK/test/x
+! go list .
+stderr 'found GLOCKFILE in .*[/\\]test'
+stderr '\s*cd \.\. && go mod init'
+
+# The command we suggested should succeed.
+cd ..
+go mod init
go list -m all
stdout '^m$'
diff --git a/src/cmd/go/testdata/script/mod_convert_godeps.txt b/src/cmd/go/testdata/script/mod_convert_godeps.txt
index 61fbab1..da7b6c1 100644
--- a/src/cmd/go/testdata/script/mod_convert_godeps.txt
+++ b/src/cmd/go/testdata/script/mod_convert_godeps.txt
@@ -1,6 +1,15 @@
env GO111MODULE=on
+# We should not create a go.mod file unless the user ran 'go mod init' explicitly.
+# However, we should suggest 'go mod init' if we can find an alternate config file.
cd $WORK/test/x
+! go list .
+stderr 'found Godeps/Godeps.json in .*[/\\]test'
+stderr '\s*cd \.\. && go mod init'
+
+# The command we suggested should succeed.
+cd ..
+go mod init
go list -m all
stdout '^m$'
diff --git a/src/cmd/go/testdata/script/mod_convert_tsv.txt b/src/cmd/go/testdata/script/mod_convert_tsv.txt
index 5b82d85..6015ac8 100644
--- a/src/cmd/go/testdata/script/mod_convert_tsv.txt
+++ b/src/cmd/go/testdata/script/mod_convert_tsv.txt
@@ -1,6 +1,15 @@
env GO111MODULE=on
+# We should not create a go.mod file unless the user ran 'go mod init' explicitly.
+# However, we should suggest 'go mod init' if we can find an alternate config file.
cd $WORK/test/x
+! go list .
+stderr 'found dependencies.tsv in .*[/\\]test'
+stderr '\s*cd \.\. && go mod init'
+
+# The command we suggested should succeed.
+cd ..
+go mod init
go list -m all
stdout '^m$'
diff --git a/src/cmd/go/testdata/script/mod_convert_vendor_conf.txt b/src/cmd/go/testdata/script/mod_convert_vendor_conf.txt
index b45d3b6..57ec419 100644
--- a/src/cmd/go/testdata/script/mod_convert_vendor_conf.txt
+++ b/src/cmd/go/testdata/script/mod_convert_vendor_conf.txt
@@ -1,6 +1,15 @@
env GO111MODULE=on
+# We should not create a go.mod file unless the user ran 'go mod init' explicitly.
+# However, we should suggest 'go mod init' if we can find an alternate config file.
cd $WORK/test/x
+! go list .
+stderr 'found vendor.conf in .*[/\\]test'
+stderr '\s*cd \.\. && go mod init'
+
+# The command we suggested should succeed.
+cd ..
+go mod init
go list -m all
stdout '^m$'
diff --git a/src/cmd/go/testdata/script/mod_convert_vendor_json.txt b/src/cmd/go/testdata/script/mod_convert_vendor_json.txt
index cb6e5fe..47d111d 100644
--- a/src/cmd/go/testdata/script/mod_convert_vendor_json.txt
+++ b/src/cmd/go/testdata/script/mod_convert_vendor_json.txt
@@ -1,6 +1,15 @@
env GO111MODULE=on
+# We should not create a go.mod file unless the user ran 'go mod init' explicitly.
+# However, we should suggest 'go mod init' if we can find an alternate config file.
cd $WORK/test/x
+! go list .
+stderr 'found vendor/vendor.json in .*[/\\]test'
+stderr '\s*cd \.\. && go mod init'
+
+# The command we suggested should succeed.
+cd ..
+go mod init
go list -m all
stdout '^m$'
diff --git a/src/cmd/go/testdata/script/mod_convert_vendor_manifest.txt b/src/cmd/go/testdata/script/mod_convert_vendor_manifest.txt
index bcf1851..68edb9d 100644
--- a/src/cmd/go/testdata/script/mod_convert_vendor_manifest.txt
+++ b/src/cmd/go/testdata/script/mod_convert_vendor_manifest.txt
@@ -1,6 +1,15 @@
env GO111MODULE=on
+# We should not create a go.mod file unless the user ran 'go mod init' explicitly.
+# However, we should suggest 'go mod init' if we can find an alternate config file.
cd $WORK/test/x
+! go list .
+stderr 'found vendor/manifest in .*[/\\]test'
+stderr '\s*cd \.\. && go mod init'
+
+# The command we suggested should succeed.
+cd ..
+go mod init
go list -m all
stdout '^m$'
diff --git a/src/cmd/go/testdata/script/mod_convert_vendor_yml.txt b/src/cmd/go/testdata/script/mod_convert_vendor_yml.txt
index 0cd245b..4ed140a 100644
--- a/src/cmd/go/testdata/script/mod_convert_vendor_yml.txt
+++ b/src/cmd/go/testdata/script/mod_convert_vendor_yml.txt
@@ -1,6 +1,15 @@
env GO111MODULE=on
+# We should not create a go.mod file unless the user ran 'go mod init' explicitly.
+# However, we should suggest 'go mod init' if we can find an alternate config file.
cd $WORK/test/x
+! go list .
+stderr 'found vendor.yml in .*[/\\]test'
+stderr '\s*cd \.\. && go mod init'
+
+# The command we suggested should succeed.
+cd ..
+go mod init
go list -m all
stdout '^m$'
diff --git a/src/cmd/go/testdata/script/mod_find.txt b/src/cmd/go/testdata/script/mod_find.txt
index f4ac8d0..eb7f974 100644
--- a/src/cmd/go/testdata/script/mod_find.txt
+++ b/src/cmd/go/testdata/script/mod_find.txt
@@ -43,6 +43,13 @@
stderr 'empty'
rm go.mod
+# In Plan 9, directories are automatically created in /n.
+# For example, /n/go.mod always exist, but it's a directory.
+# Test that we ignore directories when trying to find go.mod.
+cd $WORK/gomoddir
+! go list .
+stderr 'cannot find main module'
+
[!symlink] stop
# gplink1/src/empty where gopathlink -> GOPATH
@@ -89,3 +96,8 @@
package z
-- $GOPATH/src/example.com/x/y/z/Godeps/Godeps.json --
{"ImportPath": "unexpected.com/z"}
+
+-- $WORK/gomoddir/go.mod/README.txt --
+../go.mod is a directory, not a file.
+-- $WORK/gomoddir/p.go --
+package p
