[init] init config should return error if already exists (jetify-com#2346)

## Summary This fixes a NPE in autodetect. Previously when initializing a config with a directory that already contained a config we would return `(nil, nil)` but this is a mistake and a bit inconsistent with typical go. This changes it so that if config already exists we return an error instead. IMO this also provides better UX displaying a message indicating config already exists. This does have a minor backward compatibility issue. If users where used to calling `devbox init` and having it not fail they would now need to first test if devbox.json already exists. ## How was it tested?

Author: mikeland73

internal/boxcli/global.go

@@ -63,7 +63,7 @@ func ensureGlobalConfig() (string, error) {
 if err != nil {
 return "", err
 }
-err = devbox.InitConfig(globalConfigPath)
+err = devbox.EnsureConfig(globalConfigPath)
 if err != nil {
 return "", err
 }

internal/boxcli/init.go

@@ -5,11 +5,13 @@ package boxcli
 
 import (
 "fmt"
+"os"
 
 "github.com/pkg/errors"
 "github.com/spf13/cobra"
 
 "go.jetpack.io/devbox/internal/devbox"
+"go.jetpack.io/devbox/internal/ux"
 "go.jetpack.io/devbox/pkg/autodetect"
 )
 
@@ -28,7 +30,16 @@ func initCmd() *cobra.Command {
 "You can then add packages using `devbox add`",
 Args: cobra.MaximumNArgs(1),
 RunE: func(cmd *cobra.Command, args []string) error {
-return runInitCmd(cmd, args, flags)
+err := runInitCmd(cmd, args, flags)
+if errors.Is(err, os.ErrExist) {
+path := pathArg(args)
+if path == "" || path == "." {
+path, _ = os.Getwd()
+}
+ux.Fwarningf(cmd.ErrOrStderr(), "devbox.json already exists in %q.", path)
+err = nil
+}
+return err
 },
 }
 

internal/devbox/devbox.go

@@ -76,6 +76,14 @@ func InitConfig(dir string) error {
 return err
 }
 
+func EnsureConfig(dir string) error {
+err := InitConfig(dir)
+if err != nil && !errors.Is(err, os.ErrExist) {
+return err
+}
+return nil
+}
+
 func Open(opts *devopt.Opts) (*Devbox, error) {
 var cfg *devconfig.Config
 var err error

internal/devbox/util.go

@@ -55,7 +55,7 @@ func ensureDevboxUtilityConfig() (string, error) {
 return "", err
 }
 
-err = InitConfig(path)
+err = EnsureConfig(path)
 if err != nil {
 return "", err
 }

internal/devconfig/init.go

@@ -4,7 +4,6 @@
 package devconfig
 
 import (
-"errors"
 "os"
 "path/filepath"
 
@@ -17,11 +16,6 @@ func Init(dir string) (*Config, error) {
 os.O_RDWR|os.O_CREATE|os.O_EXCL,
 0o644,
 )
-if errors.Is(err, os.ErrExist) {
-// TODO: Should we return an error here?
-// If we do, it breaks a bunch of tests, but it's likely the correct behavior
-return nil, nil
-}
 if err != nil {
 return nil, err
 }

testscripts/init/empty.test.txt

@@ -6,8 +6,9 @@ exists devbox.json
 
 json.superset devbox.json expected.json
 
-# Second init should be a no-op.
+# Second init should be a no-op with a warning
 exec devbox init
+stderr 'devbox.json already exists in'
 
 -- expected.json --
 {