Fix 2 "bugs" found when setting up puku in a new repository (#123)

ChangeLog

@@ -1,3 +1,8 @@
+Version 1.11.1
+-------------
+    * Fix a bug causing a panic when the third party directory is misconfigured
+    * Add the filename to the error message seen if a puku.json file is malformed
+
 Version 1.11.0
 -------------
     * Make puku rewrite build files by default, with a flag to skip rewriting

VERSION

@@ -1 +1 @@
-1.11.0
+1.11.1

config/config.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"encoding/json"
+	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
@@ -102,7 +103,7 @@ func readOneConfig(path string) (*Config, error) {
 
 	c := new(Config)
 	if err := json.Unmarshal(f, c); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("in %s: %w", path, err)
 	}
 
 	configs[path] = c

generate/generate.go

@@ -88,7 +88,11 @@ func UpdateToStdout(format string, plzConf *please.Config, opts options.Options,
 }
 
 func (u *updater) readAllModules(conf *config.Config) error {
-	return filepath.WalkDir(conf.GetThirdPartyDir(), func(path string, info fs.DirEntry, _ error) error {
+	return filepath.WalkDir(conf.GetThirdPartyDir(), func(path string, info fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+
 		for _, buildFileName := range u.plzConf.BuildFileNames() {
 			if info.Name() == buildFileName {
 				file, err := u.graph.LoadFile(filepath.Dir(path))