WIP: structured error, funcr.PseudoStruct

examples/go.mod

@@ -3,7 +3,7 @@ module example
 go 1.13
 
 require (
-	github.com/go-logr/logr v1.2.2
+	github.com/go-logr/logr v1.2.3
 	github.com/go-logr/zapr v1.2.3
 	github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b
 	go.uber.org/goleak v1.1.12
@@ -12,3 +12,5 @@ require (
 )
 
 replace k8s.io/klog/v2 => ../
+
+replace github.com/go-logr/logr => github.com/pohly/logr v1.0.1-0.20221206165918-68f59133d07f

examples/go.sum

@@ -1,7 +1,6 @@
 github.com/benbjohnson/clock v1.1.0 h1:Q92kusRqC1XV2MjkWETPvjJVqKetz1OzxZB7mHJLju8=
 github.com/benbjohnson/clock v1.1.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-logr/logr v1.2.0/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
@@ -22,17 +21,14 @@ github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINE
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
-github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
-github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/pohly/logr v1.0.1-0.20221206165918-68f59133d07f h1:g9oE7e/zc3yns7MXB0HCoQoEZM4oU/JZy2V/lFrhTVM=
+github.com/pohly/logr v1.0.1-0.20221206165918-68f59133d07f/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
 github.com/spf13/afero v1.2.2/go.mod h1:9ZxEEn6pIJ8Rxe320qSDBk6AsU0r9pR7Q4OcevTdifk=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
-github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
 go.uber.org/atomic v1.7.0 h1:ADUqmZGgLDDfbSL9ZmPxKTybcoEYHgpYfELNoN+7hsw=
@@ -45,57 +41,43 @@ go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9i
 go.uber.org/zap v1.19.0 h1:mZQZefskPPCMIBCSEH0v2/iUqqLrYtaeqwD6FUGUnFE=
 go.uber.org/zap v1.19.0/go.mod h1:xg/QME4nWcxGxrpdeYfq7UvYrLh66cuVKdrbD1XF/NI=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
-golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
-golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/mod v0.4.2 h1:Gz96sIWK3OalVv/I/qNygP42zyoKp3xptRVCWRFEBvo=
 golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210510120138-977fb7262007 h1:gG67DSER+11cZvqIMb8S8bt0vZtiN6xWYARwirrOSfE=
 golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
-golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20191108193012-7d206e10da11/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.5 h1:ouewzE6p+/VEB31YYnTbEJdi8pFqKp4P4n85vwo3DHA=
 golang.org/x/tools v0.1.5/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b h1:h8qDotaEPuJATrMmW04NCwg7v22aHH28wwpauUhK9Oo=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 k8s.io/utils v0.0.0-20220210201930-3a6ce19ff2f9 h1:HNSDgDCrr/6Ly3WEGKZftiE7IY19Vz2GdbOCyI4qqhc=

go.mod

@@ -2,4 +2,6 @@ module k8s.io/klog/v2
 
 go 1.13
 
-require github.com/go-logr/logr v1.2.0
+require github.com/go-logr/logr v1.2.3
+
+replace github.com/go-logr/logr => github.com/pohly/logr v1.0.1-0.20221206165918-68f59133d07f

go.sum

@@ -1,2 +1,6 @@
 github.com/go-logr/logr v1.2.0 h1:QK40JKJyMdUDz+h+xvCsru/bJhvG0UxvePV0ufL/AcE=
 github.com/go-logr/logr v1.2.0/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/pohly/logr v1.0.1-0.20221206165918-68f59133d07f h1:g9oE7e/zc3yns7MXB0HCoQoEZM4oU/JZy2V/lFrhTVM=
+github.com/pohly/logr v1.0.1-0.20221206165918-68f59133d07f/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/pohly/logr v1.0.1-0.20221206175035-8b691a4dd7a4 h1:gWuiztcBCEUMdJC+UNFdcd7u7A/h7cv2cBabRvdxAyU=
+github.com/pohly/logr v1.0.1-0.20221206175035-8b691a4dd7a4/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=

internal/serialize/keyvalues.go

@@ -22,6 +22,7 @@ import (
 	"strconv"
 
 	"github.com/go-logr/logr"
+	funcrtypes "github.com/go-logr/logr/funcr/types"
 )
 
 // WithValues implements LogSink.WithValues. The old key/value pairs are
@@ -104,66 +105,80 @@ func KVListFormat(b *bytes.Buffer, keysAndValues ...interface{}) {
 		} else {
 			v = missingValue
 		}
-		b.WriteByte(' ')
-		// Keys are assumed to be well-formed according to
-		// https://github.com/kubernetes/community/blob/master/contributors/devel/sig-instrumentation/migration-to-structured-logging.md#name-arguments
-		// for the sake of performance. Keys with spaces,
-		// special characters, etc. will break parsing.
-		if sK, ok := k.(string); ok {
-			// Avoid one allocation when the key is a string, which
-			// normally it should be.
-			b.WriteString(sK)
-		} else {
-			b.WriteString(fmt.Sprintf("%s", k))
-		}
+		formatKV(b, k, v)
+	}
+}
 
-		// The type checks are sorted so that more frequently used ones
-		// come first because that is then faster in the common
-		// cases. In Kubernetes, ObjectRef (a Stringer) is more common
-		// than plain strings
-		// (https://github.com/kubernetes/kubernetes/pull/106594#issuecomment-975526235).
-		switch v := v.(type) {
-		case fmt.Stringer:
-			writeStringValue(b, true, StringerToString(v))
+func formatKV(b *bytes.Buffer, k, v interface{}) {
+	b.WriteByte(' ')
+	// Keys are assumed to be well-formed according to
+	// https://github.com/kubernetes/community/blob/master/contributors/devel/sig-instrumentation/migration-to-structured-logging.md#name-arguments
+	// for the sake of performance. Keys with spaces,
+	// special characters, etc. will break parsing.
+	kStr := ""
+	if sK, ok := k.(string); ok {
+		kStr = sK
+	} else {
+		kStr = fmt.Sprintf("%s", k)
+	}
+	b.WriteString(kStr)
+
+	// The type checks are sorted so that more frequently used ones
+	// come first because that is then faster in the common
+	// cases. In Kubernetes, ObjectRef (a Stringer) is more common
+	// than plain strings
+	// (https://github.com/kubernetes/kubernetes/pull/106594#issuecomment-975526235).
+	switch v := v.(type) {
+	case fmt.Stringer:
+		writeStringValue(b, true, StringerToString(v))
+	case string:
+		writeStringValue(b, true, v)
+	case error:
+		writeStringValue(b, true, ErrorToString(v))
+		// It might *also* implement logr.Marshaler to get additional values
+		// logged.
+		if marshaler, ok := v.(logr.Marshaler); ok {
+			value := marshaler.MarshalLog()
+			formatKV(b, kStr+"Details", value)
+		}
+	case logr.Marshaler:
+		value := MarshalerToValue(v)
+		// A marshaler that returns a string is useful for
+		// delayed formatting of complex values. We treat this
+		// case like a normal string. This is useful for
+		// multi-line support.
+		//
+		// We could do this by recursively formatting a value,
+		// but that comes with the risk of infinite recursion
+		// if a marshaler returns itself. Instead we call it
+		// only once and rely on it returning the intended
+		// value directly.
+		switch value := value.(type) {
 		case string:
-			writeStringValue(b, true, v)
-		case error:
-			writeStringValue(b, true, ErrorToString(v))
-		case logr.Marshaler:
-			value := MarshalerToValue(v)
-			// A marshaler that returns a string is useful for
-			// delayed formatting of complex values. We treat this
-			// case like a normal string. This is useful for
-			// multi-line support.
-			//
-			// We could do this by recursively formatting a value,
-			// but that comes with the risk of infinite recursion
-			// if a marshaler returns itself. Instead we call it
-			// only once and rely on it returning the intended
-			// value directly.
-			switch value := value.(type) {
-			case string:
-				writeStringValue(b, true, value)
-			default:
-				writeStringValue(b, false, fmt.Sprintf("%+v", value))
-			}
-		case []byte:
-			// In https://github.com/kubernetes/klog/pull/237 it was decided
-			// to format byte slices with "%+q". The advantages of that are:
-			// - readable output if the bytes happen to be printable
-			// - non-printable bytes get represented as unicode escape
-			//   sequences (\uxxxx)
-			//
-			// The downsides are that we cannot use the faster
-			// strconv.Quote here and that multi-line output is not
-			// supported. If developers know that a byte array is
-			// printable and they want multi-line output, they can
-			// convert the value to string before logging it.
-			b.WriteByte('=')
-			b.WriteString(fmt.Sprintf("%+q", v))
+			writeStringValue(b, true, value)
+		case funcrtypes.PseudoStruct:
+			writeKeysAndValues(b, []interface{}(value))
 		default:
-			writeStringValue(b, false, fmt.Sprintf("%+v", v))
+			writeStringValue(b, false, fmt.Sprintf("%+v", value))
 		}
+	case funcrtypes.PseudoStruct:
+		writeKeysAndValues(b, []interface{}(v))
+	case []byte:
+		// In https://github.com/kubernetes/klog/pull/237 it was decided
+		// to format byte slices with "%+q". The advantages of that are:
+		// - readable output if the bytes happen to be printable
+		// - non-printable bytes get represented as unicode escape
+		//   sequences (\uxxxx)
+		//
+		// The downsides are that we cannot use the faster
+		// strconv.Quote here and that multi-line output is not
+		// supported. If developers know that a byte array is
+		// printable and they want multi-line output, they can
+		// convert the value to string before logging it.
+		b.WriteByte('=')
+		b.WriteString(fmt.Sprintf("%+q", v))
+	default:
+		writeStringValue(b, false, fmt.Sprintf("%+v", v))
 	}
 }
 
@@ -251,3 +266,17 @@ func writeStringValue(b *bytes.Buffer, quote bool, v string) {
 		b.WriteString("\n >")
 	}
 }
+
+func writeKeysAndValues(b *bytes.Buffer, keysAndValues []interface{}) {
+	b.WriteString("={")
+	for i := 0; i < len(keysAndValues); i += 2 {
+		var value interface{}
+		if i+1 < len(keysAndValues) {
+			value = keysAndValues[i+1]
+		} else {
+			value = missingValue
+		}
+		formatKV(b, keysAndValues[i], value)
+	}
+	b.WriteString(" }")
+}

test/output.go

@@ -37,6 +37,7 @@ import (
 	"time"
 
 	"github.com/go-logr/logr"
+	funcrtypes "github.com/go-logr/logr/funcr/types"
 
 	"k8s.io/klog/v2"
 )
@@ -386,6 +387,30 @@ I output.go:<LINE>] "test" firstKey=1 secondKey=3
 			text:       "map keys",
 			values:     []interface{}{map[string]bool{"test": true}, "test"},
 			expectedOutput: `I output.go:<LINE>] "map keys" map[test:%!s(bool=true)]="test"
+`,
+		},
+		"structured error": {
+			text: "structured error",
+			err:  structuredError{error: errors.New("fake error"), Attributes: funcrtypes.PseudoStruct{"x", 1, "y", "multi-line\nstring"}},
+			expectedOutput: `E output.go:<LINE>] "structured error" err="fake error" errDetails={ x=1 y=<
+	multi-line
+	string
+ > }
+`,
+		},
+		"structured error value": {
+			text:   "structured error",
+			values: []interface{}{"someErr", structuredError{error: errors.New("fake error"), Attributes: funcrtypes.PseudoStruct{"x", 1, "y", "multi-line\nstring"}}},
+			expectedOutput: `I output.go:<LINE>] "structured error" someErr="fake error" someErrDetails={ x=1 y=<
+	multi-line
+	string
+ > }
+`,
+		},
+		"KeysAndValues": {
+			text:   "keys and values",
+			values: []interface{}{"parent", funcrtypes.PseudoStruct{"boolsub", true, "intsub", 1, "recursive", funcrtypes.PseudoStruct{"sub", "level2"}}},
+			expectedOutput: `I output.go:<LINE>] "keys and values" parent={ boolsub=true intsub=1 recursive={ sub="level2" } }
 `,
 		},
 	}
@@ -846,3 +871,16 @@ func (f faultyError) Error() string {
 }
 
 var _ error = faultyError{}
+
+// Structured error with additional values that are not part of the message
+// returned by Error().
+type structuredError struct {
+	error
+	Attributes funcrtypes.PseudoStruct
+}
+
+// MarshalLog gets called in addition to Error function to
+// log additional information.
+func (err structuredError) MarshalLog() interface{} {
+	return err.Attributes
+}

test/zapr.go

@@ -232,6 +232,24 @@ I output.go:<LINE>] "odd WithValues" keyWithoutValue="(MISSING)"
 		`I output.go:<LINE>] "map keys" map[test:%!s(bool=true)]="test"
 `: `{"caller":"test/output.go:<LINE>","msg":"non-string key argument passed to logging, ignoring all later arguments","invalid key":{"test":true}}
 {"caller":"test/output.go:<LINE>","msg":"map keys","v":0}
+`,
+		// In contrast to klogr, zapr doesn't resolve recursive usage
+		// of KeysAndValues and falls back to the normal zap behavior
+		// for the instance inside. That's okay.
+		`I output.go:<LINE>] "keys and values" parent={ boolsub=true intsub=1 recursive={ sub="level2" } }
+`: `{"caller":"test/output.go:<LINE>","msg":"keys and values","v":0,"parent":{"boolsub":true,"intsub":1,"recursive":[{"Key":"sub","Value":"level2"}]}}
+`,
+		`E output.go:<LINE>] "structured error" err="fake error" errDetails={ x=1 y=<
+	multi-line
+	string
+ > }
+`: `{"caller":"test/output.go:<LINE>","msg":"structured error","err":"fake error","errDetails":{"x":1,"y":"multi-line\nstring"}}
+`,
+		`I output.go:<LINE>] "structured error" someErr="fake error" someErrDetails={ x=1 y=<
+	multi-line
+	string
+ > }
+`: `{"caller":"test/output.go:<LINE>","msg":"structured error","v":0,"someErr":"fake error","someErrDetails":{"x":1,"y":"multi-line\nstring"}}
 `,
 	}
 }