update github.com/compose-spec/compose-go to v1.2.7

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

vendor/github.com/compose-spec/compose-go/dotenv/parser.go

@@ -18,6 +18,9 @@ const (
 
 func parseBytes(src []byte, out map[string]string, lookupFn LookupFn) error {
 	cutset := src
+	if lookupFn == nil {
+		lookupFn = noLookupFn
+	}
 	for {
 		cutset = getStatementStart(cutset)
 		if cutset == nil {
@@ -34,9 +37,6 @@ func parseBytes(src []byte, out map[string]string, lookupFn LookupFn) error {
 		}
 
 		if inherited {
-			if lookupFn == nil {
-				lookupFn = noLookupFn
-			}
 
 			value, ok := lookupFn(key)
 			if ok {
@@ -50,6 +50,9 @@ func parseBytes(src []byte, out map[string]string, lookupFn LookupFn) error {
 		if err != nil {
 			return err
 		}
+		if lookUpValue, ok := lookupFn(key); ok {
+			value = lookUpValue
+		}
 
 		out[key] = value
 		cutset = left

vendor/github.com/compose-spec/compose-go/loader/full-example.yml

@@ -22,6 +22,9 @@ services:
           uid: '103'
           gid: '103'
           mode: 0440
+      tags:
+        - foo:v1.0.0
+        - docker.io/username/foo:my-other-tag
 
 
     cap_add:
@@ -402,6 +405,7 @@ configs:
     external: true
   config4:
     name: foo
+    file: ~/config_data
     x-bar: baz
     x-foo: bar
 
@@ -417,6 +421,7 @@ secrets:
     external: true
   secret4:
     name: bar
+    environment: BAR
     x-bar: baz
     x-foo: bar
 x-bar: baz

vendor/github.com/compose-spec/compose-go/loader/loader.go

@@ -24,7 +24,6 @@ import (
 	"path/filepath"
 	"reflect"
 	"regexp"
-	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -70,7 +69,7 @@ type Options struct {
 }
 
 func (o *Options) SetProjectName(name string, imperativelySet bool) {
-	o.projectName = normalizeProjectName(name)
+	o.projectName = NormalizeProjectName(name)
 	o.projectNameImperativelySet = imperativelySet
 }
 
@@ -209,7 +208,7 @@ func Load(configDetails types.ConfigDetails, options ...func(*Options)) (*types.
 	}
 
 	projectName, projectNameImperativelySet := opts.GetProjectName()
-	model.Name = normalizeProjectName(model.Name)
+	model.Name = NormalizeProjectName(model.Name)
 	if !projectNameImperativelySet && model.Name != "" {
 		projectName = model.Name
 	}
@@ -246,7 +245,7 @@ func Load(configDetails types.ConfigDetails, options ...func(*Options)) (*types.
 	return project, nil
 }
 
-func normalizeProjectName(s string) string {
+func NormalizeProjectName(s string) string {
 	r := regexp.MustCompile("[a-z0-9_-]")
 	s = strings.ToLower(s)
 	s = strings.Join(r.FindAllString(s, -1), "")
@@ -385,7 +384,7 @@ func createTransformHook(additionalTransformers ...Transformer) mapstructure.Dec
 		reflect.TypeOf(types.MappingWithEquals{}):                transformMappingOrListFunc("=", true),
 		reflect.TypeOf(types.Labels{}):                           transformMappingOrListFunc("=", false),
 		reflect.TypeOf(types.MappingWithColon{}):                 transformMappingOrListFunc(":", false),
-		reflect.TypeOf(types.HostsList{}):                        transformListOrMappingFunc(":", false),
+		reflect.TypeOf(types.HostsList{}):                        transformMappingOrListFunc(":", false),
 		reflect.TypeOf(types.ServiceVolumeConfig{}):              transformServiceVolumeConfig,
 		reflect.TypeOf(types.BuildConfig{}):                      transformBuildConfig,
 		reflect.TypeOf(types.Duration(0)):                        transformStringToDuration,
@@ -571,18 +570,18 @@ func LoadService(name string, serviceDict map[string]interface{}, workingDir str
 		if volume.Type != types.VolumeTypeBind {
 			continue
 		}
-
 		if volume.Source == "" {
 			return nil, errors.New(`invalid mount config for type "bind": field Source must not be empty`)
 		}
 
-		if resolvePaths {
-			serviceConfig.Volumes[i] = resolveVolumePath(volume, workingDir, lookupEnv)
+		if resolvePaths || convertPaths {
+			volume = resolveVolumePath(volume, workingDir, lookupEnv)
 		}
 
 		if convertPaths {
-			serviceConfig.Volumes[i] = convertVolumePath(volume)
+			volume = convertVolumePath(volume)
 		}
+		serviceConfig.Volumes[i] = volume
 	}
 
 	return serviceConfig, nil
@@ -805,7 +804,7 @@ func loadFileObjectConfig(name string, objType string, obj types.FileObjectConfi
 			return obj, errors.Errorf("%[1]s %[2]s: %[1]s.driver and %[1]s.file conflict; only use %[1]s.driver", objType, name)
 		}
 	default:
-		if resolvePaths {
+		if obj.File != "" && resolvePaths {
 			obj.File = absPath(details.WorkingDir, obj.File)
 		}
 	}
@@ -1060,22 +1059,6 @@ func transformMappingOrListFunc(sep string, allowNil bool) TransformerFunc {
 	}
 }
 
-func transformListOrMappingFunc(sep string, allowNil bool) TransformerFunc {
-	return func(data interface{}) (interface{}, error) {
-		return transformListOrMapping(data, sep, allowNil)
-	}
-}
-
-func transformListOrMapping(listOrMapping interface{}, sep string, allowNil bool) (interface{}, error) {
-	switch value := listOrMapping.(type) {
-	case map[string]interface{}:
-		return toStringList(value, sep, allowNil), nil
-	case []interface{}:
-		return listOrMapping, nil
-	}
-	return nil, errors.Errorf("expected a map or a list, got %T: %#v", listOrMapping, listOrMapping)
-}
-
 func transformMappingOrList(mappingOrList interface{}, sep string, allowNil bool) (interface{}, error) {
 	switch value := mappingOrList.(type) {
 	case map[string]interface{}:
@@ -1168,15 +1151,3 @@ func toString(value interface{}, allowNil bool) interface{} {
 		return ""
 	}
 }
-
-func toStringList(value map[string]interface{}, separator string, allowNil bool) []string {
-	var output []string
-	for key, value := range value {
-		if value == nil && !allowNil {
-			continue
-		}
-		output = append(output, fmt.Sprintf("%s%s%s", key, separator, value))
-	}
-	sort.Strings(output)
-	return output
-}

vendor/github.com/compose-spec/compose-go/loader/validate.go

@@ -68,5 +68,15 @@ func checkConsistency(project *types.Project) error {
 			}
 		}
 	}
+
+	for name, secret := range project.Secrets {
+		if secret.External.External {
+			continue
+		}
+		if secret.File == "" && secret.Environment == "" {
+			return errors.Wrap(errdefs.ErrInvalid, fmt.Sprintf("secret %q must declare either `file` or `environment`", name))
+		}
+	}
+
 	return nil
 }

vendor/github.com/compose-spec/compose-go/schema/compose-spec.json

@@ -102,7 +102,8 @@
                 "shm_size": {"type": ["integer", "string"]},
                 "extra_hosts": {"$ref": "#/definitions/list_or_dict"},
                 "isolation": {"type": "string"},
-                "secrets": {"$ref": "#/definitions/service_config_or_secret"}
+                "secrets": {"$ref": "#/definitions/service_config_or_secret"},
+                "tags": {"type": "array", "items": {"type": "string"}}
               },
               "additionalProperties": false,
               "patternProperties": {"^x-": {}}
@@ -684,6 +685,7 @@
       "type": "object",
       "properties": {
         "name": {"type": "string"},
+        "environment": {"type": "string"},
         "file": {"type": "string"},
         "external": {
           "type": ["boolean", "object"],

vendor/github.com/compose-spec/compose-go/types/config.go

@@ -18,10 +18,17 @@ package types
 
 import (
 	"encoding/json"
+	"runtime"
+	"strings"
 
 	"github.com/mitchellh/mapstructure"
 )
 
+var (
+	// isCaseInsensitiveEnvVars is true on platforms where environment variable names are treated case-insensitively.
+	isCaseInsensitiveEnvVars = (runtime.GOOS == "windows")
+)
+
 // ConfigDetails are the details about a group of ConfigFiles
 type ConfigDetails struct {
 	Version     string
@@ -33,7 +40,21 @@ type ConfigDetails struct {
 // LookupEnv provides a lookup function for environment variables
 func (cd ConfigDetails) LookupEnv(key string) (string, bool) {
 	v, ok := cd.Environment[key]
-	return v, ok
+	if !isCaseInsensitiveEnvVars || ok {
+		return v, ok
+	}
+	// variable names must be treated case-insensitively on some platforms (that is, Windows).
+	// Resolves in this way:
+	// * Return the value if its name matches with the passed name case-sensitively.
+	// * Otherwise, return the value if its lower-cased name matches lower-cased passed name.
+	//     * The value is indefinite if multiple variables match.
+	lowerKey := strings.ToLower(key)
+	for k, v := range cd.Environment {
+		if strings.ToLower(k) == lowerKey {
+			return v, true
+		}
+	}
+	return "", false
 }
 
 // ConfigFile is a filename and the contents of the file as a Dict

vendor/github.com/compose-spec/compose-go/types/types.go

@@ -305,6 +305,7 @@ type BuildConfig struct {
 	Network    string                `yaml:",omitempty" json:"network,omitempty"`
 	Target     string                `yaml:",omitempty" json:"target,omitempty"`
 	Secrets    []ServiceSecretConfig `yaml:",omitempty" json:"secrets,omitempty"`
+	Tags       StringList            `mapstructure:"tags" yaml:"tags,omitempty" json:"tags,omitempty"`
 
 	Extensions map[string]interface{} `yaml:",inline" json:"-"`
 }
@@ -468,7 +469,16 @@ func (s SSHKey) MarshalJSON() ([]byte, error) {
 type MappingWithColon map[string]string
 
 // HostsList is a list of colon-separated host-ip mappings
-type HostsList []string
+type HostsList map[string]string
+
+// AsList return host-ip mappings as a list of colon-separated strings
+func (h HostsList) AsList() []string {
+	l := make([]string, 0, len(h))
+	for k, v := range h {
+		l = append(l, fmt.Sprintf("%s:%s", k, v))
+	}
+	return l
+}
 
 // LoggingConfig the logging configuration for a service
 type LoggingConfig struct {
@@ -881,6 +891,7 @@ type CredentialSpecConfig struct {
 type FileObjectConfig struct {
 	Name           string                 `yaml:",omitempty" json:"name,omitempty"`
 	File           string                 `yaml:",omitempty" json:"file,omitempty"`
+	Environment    string                 `yaml:",omitempty" json:"environment,omitempty"`
 	External       External               `yaml:",omitempty" json:"external,omitempty"`
 	Labels         Labels                 `yaml:",omitempty" json:"labels,omitempty"`
 	Driver         string                 `yaml:",omitempty" json:"driver,omitempty"`

vendor/github.com/imdario/mergo/README.md

@@ -8,8 +8,7 @@
 [![Coverage Status][9]][10]
 [![Sourcegraph][11]][12]
 [![FOSSA Status][13]][14]
-
-[![GoCenter Kudos][15]][16]
+[![Become my sponsor][15]][16]
 
 [1]: https://travis-ci.org/imdario/mergo.png
 [2]: https://travis-ci.org/imdario/mergo
@@ -25,8 +24,8 @@
 [12]: https://sourcegraph.com/github.com/imdario/mergo?badge
 [13]: https://app.fossa.io/api/projects/git%2Bgithub.com%2Fimdario%2Fmergo.svg?type=shield
 [14]: https://app.fossa.io/projects/git%2Bgithub.com%2Fimdario%2Fmergo?ref=badge_shield
-[15]: https://search.gocenter.io/api/ui/badge/github.com%2Fimdario%2Fmergo
-[16]: https://search.gocenter.io/github.com/imdario/mergo
+[15]: https://img.shields.io/github/sponsors/imdario
+[16]: https://github.com/sponsors/imdario
 
 A helper to merge structs and maps in Golang. Useful for configuration default values, avoiding messy if-statements.
 
@@ -36,11 +35,11 @@ Also a lovely [comune](http://en.wikipedia.org/wiki/Mergo) (municipality) in the
 
 ## Status
 
-It is ready for production use. [It is used in several projects by Docker, Google, The Linux Foundation, VMWare, Shopify, etc](https://github.com/imdario/mergo#mergo-in-the-wild).
+It is ready for production use. [It is used in several projects by Docker, Google, The Linux Foundation, VMWare, Shopify, Microsoft, etc](https://github.com/imdario/mergo#mergo-in-the-wild).
 
 ### Important note
 
-Please keep in mind that a problematic PR broke [0.3.9](//github.com/imdario/mergo/releases/tag/0.3.9). I reverted it in [0.3.10](//github.com/imdario/mergo/releases/tag/0.3.10), and I consider it stable but not bug-free. Also, this version adds suppot for go modules.
+Please keep in mind that a problematic PR broke [0.3.9](//github.com/imdario/mergo/releases/tag/0.3.9). I reverted it in [0.3.10](//github.com/imdario/mergo/releases/tag/0.3.10), and I consider it stable but not bug-free. Also, this version adds support for go modules.
 
 Keep in mind that in [0.3.2](//github.com/imdario/mergo/releases/tag/0.3.2), Mergo changed `Merge()`and `Map()` signatures to support [transformers](#transformers). I added an optional/variadic argument so that it won't break the existing code.
 
@@ -51,12 +50,12 @@ If you were using Mergo before April 6th, 2015, please check your project works
 If Mergo is useful to you, consider buying me a coffee, a beer, or making a monthly donation to allow me to keep building great free software. :heart_eyes:
 
 <a href='https://ko-fi.com/B0B58839' target='_blank'><img height='36' style='border:0px;height:36px;' src='https://az743702.vo.msecnd.net/cdn/kofi1.png?v=0' border='0' alt='Buy Me a Coffee at ko-fi.com' /></a>
-[![Beerpay](https://beerpay.io/imdario/mergo/badge.svg)](https://beerpay.io/imdario/mergo)
-[![Beerpay](https://beerpay.io/imdario/mergo/make-wish.svg)](https://beerpay.io/imdario/mergo)
 <a href="https://liberapay.com/dario/donate"><img alt="Donate using Liberapay" src="https://liberapay.com/assets/widgets/donate.svg"></a>
+<a href='https://github.com/sponsors/imdario' target='_blank'><img alt="Become my sponsor" src="https://img.shields.io/github/sponsors/imdario?style=for-the-badge" /></a>
 
 ### Mergo in the wild
 
+- [cli/cli](https://github.com/cli/cli)
 - [moby/moby](https://github.com/moby/moby)
 - [kubernetes/kubernetes](https://github.com/kubernetes/kubernetes)
 - [vmware/dispatch](https://github.com/vmware/dispatch)
@@ -98,6 +97,8 @@ If Mergo is useful to you, consider buying me a coffee, a beer, or making a mont
 - [jnuthong/item_search](https://github.com/jnuthong/item_search)
 - [bukalapak/snowboard](https://github.com/bukalapak/snowboard)
 - [containerssh/containerssh](https://github.com/containerssh/containerssh)
+- [goreleaser/goreleaser](https://github.com/goreleaser/goreleaser)
+- [tjpnz/structbot](https://github.com/tjpnz/structbot)
 
 ## Install
 
@@ -168,7 +169,7 @@ func main() {
 
 Note: if test are failing due missing package, please execute:
 
-    go get gopkg.in/yaml.v2
+    go get gopkg.in/yaml.v3
 
 ### Transformers
 
@@ -218,7 +219,6 @@ func main() {
 }
 ```
 
-
 ## Contact me
 
 If I can help you, you have an idea or you are using Mergo in your projects, don't hesitate to drop me a line (or a pull request): [@im_dario](https://twitter.com/im_dario)
@@ -227,18 +227,6 @@ If I can help you, you have an idea or you are using Mergo in your projects, don
 
 Written by [Dario Castañé](http://dario.im).
 
-## Top Contributors
-
-[![0](https://sourcerer.io/fame/imdario/imdario/mergo/images/0)](https://sourcerer.io/fame/imdario/imdario/mergo/links/0)
-[![1](https://sourcerer.io/fame/imdario/imdario/mergo/images/1)](https://sourcerer.io/fame/imdario/imdario/mergo/links/1)
-[![2](https://sourcerer.io/fame/imdario/imdario/mergo/images/2)](https://sourcerer.io/fame/imdario/imdario/mergo/links/2)
-[![3](https://sourcerer.io/fame/imdario/imdario/mergo/images/3)](https://sourcerer.io/fame/imdario/imdario/mergo/links/3)
-[![4](https://sourcerer.io/fame/imdario/imdario/mergo/images/4)](https://sourcerer.io/fame/imdario/imdario/mergo/links/4)
-[![5](https://sourcerer.io/fame/imdario/imdario/mergo/images/5)](https://sourcerer.io/fame/imdario/imdario/mergo/links/5)
-[![6](https://sourcerer.io/fame/imdario/imdario/mergo/images/6)](https://sourcerer.io/fame/imdario/imdario/mergo/links/6)
-[![7](https://sourcerer.io/fame/imdario/imdario/mergo/images/7)](https://sourcerer.io/fame/imdario/imdario/mergo/links/7)
-
-
 ## License
 
 [BSD 3-Clause](http://opensource.org/licenses/BSD-3-Clause) license, as [Go language](http://golang.org/LICENSE).

vendor/github.com/imdario/mergo/merge.go

@@ -79,7 +79,7 @@ func deepMerge(dst, src reflect.Value, visited map[uintptr]*visit, depth int, co
 		visited[h] = &visit{addr, typ, seen}
 	}
 
-	if config.Transformers != nil && !isEmptyValue(dst) {
+	if config.Transformers != nil && !isReflectNil(dst) && dst.IsValid() {
 		if fn := config.Transformers.Transformer(dst.Type()); fn != nil {
 			err = fn(dst, src)
 			return

vendor/github.com/imdario/mergo/mergo.go

@@ -17,7 +17,7 @@ import (
 var (
 	ErrNilArguments                = errors.New("src and dst must not be nil")
 	ErrDifferentArgumentsTypes     = errors.New("src and dst must be of same type")
-	ErrNotSupported                = errors.New("only structs and maps are supported")
+	ErrNotSupported                = errors.New("only structs, maps, and slices are supported")
 	ErrExpectedMapAsDestination    = errors.New("dst was expected to be a map")
 	ErrExpectedStructAsDestination = errors.New("dst was expected to be a struct")
 	ErrNonPointerAgument           = errors.New("dst must be a pointer")
@@ -65,7 +65,7 @@ func resolveValues(dst, src interface{}) (vDst, vSrc reflect.Value, err error) {
 		return
 	}
 	vDst = reflect.ValueOf(dst).Elem()
-	if vDst.Kind() != reflect.Struct && vDst.Kind() != reflect.Map {
+	if vDst.Kind() != reflect.Struct && vDst.Kind() != reflect.Map && vDst.Kind() != reflect.Slice {
 		err = ErrNotSupported
 		return
 	}

vendor/github.com/mitchellh/mapstructure/CHANGELOG.md

@@ -1,3 +1,16 @@
+## 1.5.0
+
+* New option `IgnoreUntaggedFields` to ignore decoding to any fields
+  without `mapstructure` (or the configured tag name) set [GH-277]
+* New option `ErrorUnset` which makes it an error if any fields
+  in a target struct are not set by the decoding process. [GH-225]
+* New function `OrComposeDecodeHookFunc` to help compose decode hooks. [GH-240]
+* Decoding to slice from array no longer crashes [GH-265]
+* Decode nested struct pointers to map [GH-271]
+* Fix issue where `,squash` was ignored if `Squash` option was set. [GH-280]
+* Fix issue where fields with `,omitempty` would sometimes decode
+  into a map with an empty string key [GH-281]
+
 ## 1.4.3
 
 * Fix cases where `json.Number` didn't decode properly [GH-261]

vendor/github.com/mitchellh/mapstructure/decode_hooks.go

@@ -77,6 +77,28 @@ func ComposeDecodeHookFunc(fs ...DecodeHookFunc) DecodeHookFunc {
 	}
 }
 
+// OrComposeDecodeHookFunc executes all input hook functions until one of them returns no error. In that case its value is returned.
+// If all hooks return an error, OrComposeDecodeHookFunc returns an error concatenating all error messages.
+func OrComposeDecodeHookFunc(ff ...DecodeHookFunc) DecodeHookFunc {
+	return func(a, b reflect.Value) (interface{}, error) {
+		var allErrs string
+		var out interface{}
+		var err error
+
+		for _, f := range ff {
+			out, err = DecodeHookExec(f, a, b)
+			if err != nil {
+				allErrs += err.Error() + "\n"
+				continue
+			}
+
+			return out, nil
+		}
+
+		return nil, errors.New(allErrs)
+	}
+}
+
 // StringToSliceHookFunc returns a DecodeHookFunc that converts
 // string to []string by splitting on the given sep.
 func StringToSliceHookFunc(sep string) DecodeHookFunc {

vendor/github.com/mitchellh/mapstructure/mapstructure.go

@@ -122,7 +122,7 @@
 // field value is zero and a numeric type, the field is empty, and it won't
 // be encoded into the destination type.
 //
-//     type Source {
+//     type Source struct {
 //         Age int `mapstructure:",omitempty"`
 //     }
 //
@@ -215,6 +215,12 @@ type DecoderConfig struct {
 	// (extra keys).
 	ErrorUnused bool
 
+	// If ErrorUnset is true, then it is an error for there to exist
+	// fields in the result that were not set in the decoding process
+	// (extra fields). This only applies to decoding to a struct. This
+	// will affect all nested structs as well.
+	ErrorUnset bool
+
 	// ZeroFields, if set to true, will zero fields before writing them.
 	// For example, a map will be emptied before decoded values are put in
 	// it. If this is false, a map will be merged.
@@ -259,6 +265,10 @@ type DecoderConfig struct {
 	// defaults to "mapstructure"
 	TagName string
 
+	// IgnoreUntaggedFields ignores all struct fields without explicit
+	// TagName, comparable to `mapstructure:"-"` as default behaviour.
+	IgnoreUntaggedFields bool
+
 	// MatchName is the function used to match the map key to the struct
 	// field name or tag. Defaults to `strings.EqualFold`. This can be used
 	// to implement case-sensitive tag values, support snake casing, etc.
@@ -284,6 +294,11 @@ type Metadata struct {
 	// Unused is a slice of keys that were found in the raw value but
 	// weren't decoded since there was no matching field in the result interface
 	Unused []string
+
+	// Unset is a slice of field names that were found in the result interface
+	// but weren't set in the decoding process since there was no matching value
+	// in the input
+	Unset []string
 }
 
 // Decode takes an input structure and uses reflection to translate it to
@@ -375,6 +390,10 @@ func NewDecoder(config *DecoderConfig) (*Decoder, error) {
 		if config.Metadata.Unused == nil {
 			config.Metadata.Unused = make([]string, 0)
 		}
+
+		if config.Metadata.Unset == nil {
+			config.Metadata.Unset = make([]string, 0)
+		}
 	}
 
 	if config.TagName == "" {
@@ -906,9 +925,15 @@ func (d *Decoder) decodeMapFromStruct(name string, dataVal reflect.Value, val re
 		tagValue := f.Tag.Get(d.config.TagName)
 		keyName := f.Name
 
+		if tagValue == "" && d.config.IgnoreUntaggedFields {
+			continue
+		}
+
 		// If Squash is set in the config, we squash the field down.
 		squash := d.config.Squash && v.Kind() == reflect.Struct && f.Anonymous
 
+		v = dereferencePtrToStructIfNeeded(v, d.config.TagName)
+
 		// Determine the name of the key in the map
 		if index := strings.Index(tagValue, ","); index != -1 {
 			if tagValue[:index] == "-" {
@@ -920,7 +945,7 @@ func (d *Decoder) decodeMapFromStruct(name string, dataVal reflect.Value, val re
 			}
 
 			// If "squash" is specified in the tag, we squash the field down.
-			squash = !squash && strings.Index(tagValue[index+1:], "squash") != -1
+			squash = squash || strings.Index(tagValue[index+1:], "squash") != -1
 			if squash {
 				// When squashing, the embedded type can be a pointer to a struct.
 				if v.Kind() == reflect.Ptr && v.Elem().Kind() == reflect.Struct {
@@ -932,7 +957,9 @@ func (d *Decoder) decodeMapFromStruct(name string, dataVal reflect.Value, val re
 					return fmt.Errorf("cannot squash non-struct type '%s'", v.Type())
 				}
 			}
-			keyName = tagValue[:index]
+			if keyNameTagValue := tagValue[:index]; keyNameTagValue != "" {
+				keyName = keyNameTagValue
+			}
 		} else if len(tagValue) > 0 {
 			if tagValue == "-" {
 				continue
@@ -1088,7 +1115,7 @@ func (d *Decoder) decodeSlice(name string, data interface{}, val reflect.Value)
 	}
 
 	// If the input value is nil, then don't allocate since empty != nil
-	if dataVal.IsNil() {
+	if dataValKind != reflect.Array && dataVal.IsNil() {
 		return nil
 	}
 
@@ -1250,6 +1277,7 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 		dataValKeysUnused[dataValKey.Interface()] = struct{}{}
 	}
 
+	targetValKeysUnused := make(map[interface{}]struct{})
 	errors := make([]string, 0)
 
 	// This slice will keep track of all the structs we'll be decoding.
@@ -1354,7 +1382,8 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 
 			if !rawMapVal.IsValid() {
 				// There was no matching key in the map for the value in
-				// the struct. Just ignore.
+				// the struct. Remember it for potential errors and metadata.
+				targetValKeysUnused[fieldName] = struct{}{}
 				continue
 			}
 		}
@@ -1414,6 +1443,17 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 		errors = appendErrors(errors, err)
 	}
 
+	if d.config.ErrorUnset && len(targetValKeysUnused) > 0 {
+		keys := make([]string, 0, len(targetValKeysUnused))
+		for rawKey := range targetValKeysUnused {
+			keys = append(keys, rawKey.(string))
+		}
+		sort.Strings(keys)
+
+		err := fmt.Errorf("'%s' has unset fields: %s", name, strings.Join(keys, ", "))
+		errors = appendErrors(errors, err)
+	}
+
 	if len(errors) > 0 {
 		return &Error{errors}
 	}
@@ -1428,6 +1468,14 @@ func (d *Decoder) decodeStructFromMap(name string, dataVal, val reflect.Value) e
 
 			d.config.Metadata.Unused = append(d.config.Metadata.Unused, key)
 		}
+		for rawKey := range targetValKeysUnused {
+			key := rawKey.(string)
+			if name != "" {
+				key = name + "." + key
+			}
+
+			d.config.Metadata.Unset = append(d.config.Metadata.Unset, key)
+		}
 	}
 
 	return nil
@@ -1465,3 +1513,28 @@ func getKind(val reflect.Value) reflect.Kind {
 		return kind
 	}
 }
+
+func isStructTypeConvertibleToMap(typ reflect.Type, checkMapstructureTags bool, tagName string) bool {
+	for i := 0; i < typ.NumField(); i++ {
+		f := typ.Field(i)
+		if f.PkgPath == "" && !checkMapstructureTags { // check for unexported fields
+			return true
+		}
+		if checkMapstructureTags && f.Tag.Get(tagName) != "" { // check for mapstructure tags inside
+			return true
+		}
+	}
+	return false
+}
+
+func dereferencePtrToStructIfNeeded(v reflect.Value, tagName string) reflect.Value {
+	if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
+		return v
+	}
+	deref := v.Elem()
+	derefT := deref.Type()
+	if isStructTypeConvertibleToMap(derefT, true, tagName) {
+		return deref
+	}
+	return v
+}