Make the option WithErrorUnused enabled by default when unmarshalin…

…g configuration (#9154)

**Description:**
Make the option `WithErrorUnused` enabled by default when unmarshaling
configuration
The option `WithErrorUnused` is now enabled by default, and a new option
`WithIgnoreUnused` is introduced to ignore
errors about unused fields.

**Link to tracking Issue:**
This relates to #7102 to some extent.

**Testing:**
N/A

**Documentation:**
N/A

.chloggen/make_error_unused_default.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: confmap
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Make the option `WithErrorUnused` enabled by default when unmarshaling configuration
+
+# One or more tracking issues or pull requests related to the change
+issues: [7102]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: |
+  The option `WithErrorUnused` is now enabled by default, and a new option `WithIgnoreUnused` is introduced to ignore
+  errors about unused fields.
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

component/config.go

@@ -32,7 +32,7 @@ func UnmarshalConfig(conf *confmap.Conf, intoCfg Config) error {
 		return cu.Unmarshal(conf)
 	}
 
-	return conf.Unmarshal(intoCfg, confmap.WithErrorUnused())
+	return conf.Unmarshal(intoCfg)
 }
 
 // ConfigValidator defines an optional interface for configurations to implement to do validation.

confmap/confmap.go

@@ -51,15 +51,25 @@ type UnmarshalOption interface {
 }
 
 type unmarshalOption struct {
-	errorUnused bool
+	ignoreUnused bool
 }
 
 // WithErrorUnused sets an option to error when there are existing
 // keys in the original Conf that were unused in the decoding process
-// (extra keys).
+// (extra keys). This option is enabled by default and can be disabled with `WithIgnoreUnused`.
+// Deprecated: this is now enabled by default. Use `WithIgnoreUnused` to disable.
 func WithErrorUnused() UnmarshalOption {
 	return unmarshalOptionFunc(func(uo *unmarshalOption) {
-		uo.errorUnused = true
+		uo.ignoreUnused = false
+	})
+}
+
+// WithIgnoreUnused sets an option to ignore errors if existing
+// keys in the original Conf were unused in the decoding process
+// (extra keys).
+func WithIgnoreUnused() UnmarshalOption {
+	return unmarshalOptionFunc(func(uo *unmarshalOption) {
+		uo.ignoreUnused = true
 	})
 }
 
@@ -76,7 +86,7 @@ func (l *Conf) Unmarshal(result any, opts ...UnmarshalOption) error {
 	for _, opt := range opts {
 		opt.apply(&set)
 	}
-	return decodeConfig(l, result, set.errorUnused)
+	return decodeConfig(l, result, !set.ignoreUnused)
 }
 
 type marshalOption struct{}

confmap/confmap_test.go

@@ -149,7 +149,8 @@ func TestUnmarshalWithErrorUnused(t *testing.T) {
 		"string":  "this is a string",
 	}
 	conf := NewFromStringMap(stringMap)
-	assert.Error(t, conf.Unmarshal(&TestIDConfig{}, WithErrorUnused()))
+	assert.Error(t, conf.Unmarshal(&TestIDConfig{}))
+	assert.NoError(t, conf.Unmarshal(&TestIDConfig{}, WithIgnoreUnused()))
 }
 
 type TestConfig struct {

exporter/loggingexporter/config.go

@@ -65,7 +65,7 @@ func (cfg *Config) Unmarshal(conf *confmap.Conf) error {
 		return fmt.Errorf("'loglevel' and 'verbosity' are incompatible. Use only 'verbosity' instead")
 	}
 
-	if err := conf.Unmarshal(cfg, confmap.WithErrorUnused()); err != nil {
+	if err := conf.Unmarshal(cfg); err != nil {
 		return err
 	}
 

otelcol/internal/configunmarshaler/configs.go

@@ -23,7 +23,7 @@ func NewConfigs[F component.Factory](factories map[component.Type]F) *Configs[F]
 
 func (c *Configs[F]) Unmarshal(conf *confmap.Conf) error {
 	rawCfgs := make(map[component.ID]map[string]any)
-	if err := conf.Unmarshal(&rawCfgs, confmap.WithErrorUnused()); err != nil {
+	if err := conf.Unmarshal(&rawCfgs); err != nil {
 		return err
 	}
 

otelcol/unmarshaler.go

@@ -66,5 +66,5 @@ func unmarshal(v *confmap.Conf, factories Factories) (*configSettings, error) {
 		},
 	}
 
-	return cfg, v.Unmarshal(&cfg, confmap.WithErrorUnused())
+	return cfg, v.Unmarshal(&cfg)
 }

otelcol/unmarshaler_test.go

@@ -135,7 +135,7 @@ func TestPipelineConfigUnmarshalError(t *testing.T) {
 	for _, tt := range testCases {
 		t.Run(tt.name, func(t *testing.T) {
 			pips := new(pipelines.Config)
-			err := tt.conf.Unmarshal(&pips, confmap.WithErrorUnused())
+			err := tt.conf.Unmarshal(&pips)
 			require.Error(t, err)
 			assert.Contains(t, err.Error(), tt.expectError)
 		})
@@ -203,7 +203,7 @@ func TestServiceUnmarshalError(t *testing.T) {
 
 	for _, tt := range testCases {
 		t.Run(tt.name, func(t *testing.T) {
-			err := tt.conf.Unmarshal(&service.Config{}, confmap.WithErrorUnused())
+			err := tt.conf.Unmarshal(&service.Config{})
 			require.Error(t, err)
 			assert.Contains(t, err.Error(), tt.expectError)
 		})

receiver/otlpreceiver/config.go

@@ -60,7 +60,7 @@ func (cfg *Config) Validate() error {
 // Unmarshal a confmap.Conf into the config struct.
 func (cfg *Config) Unmarshal(conf *confmap.Conf) error {
 	// first load the config normally
-	err := conf.Unmarshal(cfg, confmap.WithErrorUnused())
+	err := conf.Unmarshal(cfg)
 	if err != nil {
 		return err
 	}