test: add fuzz and stress tests for concurrent safety

.github/workflows/lint.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
       - uses: actions/setup-go@v6
         with:
-          go-version: 1.21
+          go-version: 1.22
           stable: false
       - uses: actions/checkout@v6
       - name: golangci-lint

.github/workflows/test.yml

@@ -14,10 +14,11 @@ jobs:
       fail-fast: false
       matrix:
         go:
-          - '1.21'
           - '1.22'
           - '1.23'
           - '1.24'
+          - '1.25'
+          - '1.26'
           - '1.x'
     steps:
     - uses: actions/checkout@v6

examples/failover/go.mod

@@ -1,6 +1,6 @@
 module github.com/samber/slog-multi/examples/failover
 
-go 1.21
+go 1.22
 
 require github.com/samber/slog-multi v1.0.0
 

examples/fanout/go.mod

@@ -1,6 +1,6 @@
 module github.com/samber/slog-multi/examples/fanout
 
-go 1.21
+go 1.22
 
 require github.com/samber/slog-multi v1.0.0
 

examples/firstmatch/go.mod

@@ -1,6 +1,6 @@
 module github.com/samber/slog-multi/examples/firstmatch
 
-go 1.21
+go 1.22
 
 require (
 	github.com/samber/slog-multi v1.0.0
@@ -9,8 +9,8 @@ require (
 
 require (
 	github.com/gorilla/websocket v1.4.2 // indirect
-	github.com/samber/lo v1.51.0 // indirect
-	github.com/samber/slog-common v0.19.0 // indirect
+	github.com/samber/lo v1.52.0 // indirect
+	github.com/samber/slog-common v0.20.0 // indirect
 	github.com/slack-go/slack v0.12.1 // indirect
 	golang.org/x/text v0.22.0 // indirect
 )

examples/firstmatch/go.sum

@@ -0,0 +1,29 @@
+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-test/deep v1.0.4 h1:u2CU3YKy9I2pmu9pX0eq50wCgjfGIt539SqR7FbHiho=
+github.com/go-test/deep v1.0.4/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
+github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
+github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=
+github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+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/samber/lo v1.52.0 h1:Rvi+3BFHES3A8meP33VPAxiBZX/Aws5RxrschYGjomw=
+github.com/samber/lo v1.52.0/go.mod h1:4+MXEGsJzbKGaUEQFKBq2xtfuznW9oz/WrgyzMzRoM0=
+github.com/samber/slog-common v0.20.0 h1:WaLnm/aCvBJSk5nR5aXZTFBaV0B47A+AEaEOiZDeUnc=
+github.com/samber/slog-common v0.20.0/go.mod h1:+Ozat1jgnnE59UAlmNX1IF3IByHsODnnwf9jUcBZ+m8=
+github.com/samber/slog-slack v1.0.0 h1:HjrlufIPwhRm8Hv4Ox8khu0+0StGEbAEY4fZzOQM5qs=
+github.com/samber/slog-slack v1.0.0/go.mod h1:S0UnSLr8Vpv8+gW41dwkg589dUVT+HX2p5Y6zcehSd4=
+github.com/slack-go/slack v0.12.1 h1:X97b9g2hnITDtNsNe5GkGx6O2/Sz/uC20ejRZN6QxOw=
+github.com/slack-go/slack v0.12.1/go.mod h1:hlGi5oXA+Gt+yWTPP0plCdRKmjsDxecdHxYQdlMQKOw=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
+golang.org/x/text v0.22.0 h1:bofq7m3/HAFvbF51jz3Q9wLg3jkvSPuiZu/pD1XwgtM=
+golang.org/x/text v0.22.0/go.mod h1:YRoo4H8PVmsu+E3Ou7cqLVH8oXWIHVoX0jqUWALQhfY=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

examples/pipe/go.mod

@@ -1,6 +1,6 @@
 module github.com/samber/slog-multi/examples/pipe
 
-go 1.21
+go 1.22
 
 require (
 	github.com/samber/lo v1.47.0

examples/pool/go.mod

@@ -1,6 +1,6 @@
 module github.com/samber/slog-multi/examples/pool
 
-go 1.21
+go 1.22
 
 require github.com/samber/slog-multi v1.0.0
 

examples/router/go.mod

@@ -1,6 +1,6 @@
 module github.com/samber/slog-multi/examples/router
 
-go 1.21
+go 1.22
 
 require (
 	github.com/samber/slog-multi v1.0.0
@@ -9,8 +9,8 @@ require (
 
 require (
 	github.com/gorilla/websocket v1.4.2 // indirect
-	github.com/samber/lo v1.51.0 // indirect
-	github.com/samber/slog-common v0.19.0 // indirect
+	github.com/samber/lo v1.52.0 // indirect
+	github.com/samber/slog-common v0.20.0 // indirect
 	github.com/slack-go/slack v0.12.1 // indirect
 	golang.org/x/text v0.22.0 // indirect
 )

examples/router/go.sum

@@ -9,17 +9,17 @@ github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0U
 github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 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/samber/lo v1.51.0 h1:kysRYLbHy/MB7kQZf5DSN50JHmMsNEdeY24VzJFu7wI=
-github.com/samber/lo v1.51.0/go.mod h1:4+MXEGsJzbKGaUEQFKBq2xtfuznW9oz/WrgyzMzRoM0=
-github.com/samber/slog-common v0.19.0 h1:fNcZb8B2uOLooeYwFpAlKjkQTUafdjfqKcwcC89G9YI=
-github.com/samber/slog-common v0.19.0/go.mod h1:dTz+YOU76aH007YUU0DffsXNsGFQRQllPQh9XyNoA3M=
+github.com/samber/lo v1.52.0 h1:Rvi+3BFHES3A8meP33VPAxiBZX/Aws5RxrschYGjomw=
+github.com/samber/lo v1.52.0/go.mod h1:4+MXEGsJzbKGaUEQFKBq2xtfuznW9oz/WrgyzMzRoM0=
+github.com/samber/slog-common v0.20.0 h1:WaLnm/aCvBJSk5nR5aXZTFBaV0B47A+AEaEOiZDeUnc=
+github.com/samber/slog-common v0.20.0/go.mod h1:+Ozat1jgnnE59UAlmNX1IF3IByHsODnnwf9jUcBZ+m8=
 github.com/samber/slog-slack v1.0.0 h1:HjrlufIPwhRm8Hv4Ox8khu0+0StGEbAEY4fZzOQM5qs=
 github.com/samber/slog-slack v1.0.0/go.mod h1:S0UnSLr8Vpv8+gW41dwkg589dUVT+HX2p5Y6zcehSd4=
 github.com/slack-go/slack v0.12.1 h1:X97b9g2hnITDtNsNe5GkGx6O2/Sz/uC20ejRZN6QxOw=
 github.com/slack-go/slack v0.12.1/go.mod h1:hlGi5oXA+Gt+yWTPP0plCdRKmjsDxecdHxYQdlMQKOw=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
-github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
-github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
 go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 golang.org/x/text v0.22.0 h1:bofq7m3/HAFvbF51jz3Q9wLg3jkvSPuiZu/pD1XwgtM=

fuzz_test.go

@@ -0,0 +1,202 @@
+package slogmulti
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func buildFuzzRecord(levelInt int, msg string, attrCount int) slog.Record {
+	level := slog.Level(levelInt)
+	r := slog.NewRecord(time.Now(), level, msg, 0)
+	for i := 0; i < attrCount; i++ {
+		r.AddAttrs(slog.Int(fmt.Sprintf("k%d", i), i))
+	}
+	return r
+}
+
+func FuzzFanoutHandle(f *testing.F) {
+	f.Add(0, "hello", 3)
+	f.Add(-4, "", 0)
+	f.Add(4, "warn msg", 1)
+	f.Add(8, strings.Repeat("x", 1000), 50)
+
+	f.Fuzz(func(t *testing.T, levelInt int, msg string, attrCount int) {
+		if attrCount < 0 {
+			attrCount = 0
+		}
+		if attrCount > 50 {
+			attrCount = 50
+		}
+
+		level := slog.Level(levelInt)
+		h1 := newCountingHandler(slog.LevelDebug)
+		h2 := newCountingHandler(slog.LevelWarn)
+		h3 := newCountingHandler(slog.LevelDebug)
+
+		fanout := Fanout(h1, h2, h3)
+		r := buildFuzzRecord(levelInt, msg, attrCount)
+		err := fanout.Handle(context.Background(), r)
+		assert.NoError(t, err)
+
+		// Fanout only calls Handle on enabled handlers
+		var expected1, expected2, expected3 int64
+		if level >= slog.LevelDebug {
+			expected1 = 1
+			expected3 = 1
+		}
+		if level >= slog.LevelWarn {
+			expected2 = 1
+		}
+
+		assert.Equal(t, expected1, h1.handleCount.Load(), "h1")
+		assert.Equal(t, expected2, h2.handleCount.Load(), "h2")
+		assert.Equal(t, expected3, h3.handleCount.Load(), "h3")
+	})
+}
+
+func FuzzFailoverHandle(f *testing.F) {
+	f.Add(0, "test", true, false)
+	f.Add(0, "test", false, false)
+	f.Add(0, "test", true, true)
+	f.Add(4, "", false, true)
+
+	f.Fuzz(func(t *testing.T, levelInt int, msg string, firstFails bool, secondFails bool) {
+		// errorHandler.Enabled always returns true, countingHandler checks minLevel.
+		// Use errorHandler for both fail and success paths so Enabled is always true,
+		// avoiding level-based skipping that complicates assertions.
+		h1err := &errorHandler{err: errors.New("h1 fail")}
+		h1ok := &errorHandler{err: nil}
+		h2err := &errorHandler{err: errors.New("h2 fail")}
+		h2ok := &errorHandler{err: nil}
+
+		var h1, h2 *errorHandler
+		if firstFails {
+			h1 = h1err
+		} else {
+			h1 = h1ok
+		}
+		if secondFails {
+			h2 = h2err
+		} else {
+			h2 = h2ok
+		}
+
+		handler := Failover()(h1, h2)
+		r := buildFuzzRecord(levelInt, msg, 0)
+		err := handler.Handle(context.Background(), r)
+
+		if !firstFails {
+			assert.NoError(t, err)
+			assert.Equal(t, int64(1), h1.handleCount.Load())
+			assert.Equal(t, int64(0), h2.handleCount.Load())
+		} else if !secondFails {
+			assert.NoError(t, err)
+			assert.Equal(t, int64(1), h2.handleCount.Load())
+		} else {
+			assert.Error(t, err)
+		}
+	})
+}
+
+func FuzzPoolHandle(f *testing.F) {
+	f.Add(0, "hello")
+	f.Add(-4, "")
+	f.Add(8, strings.Repeat("a", 500))
+
+	f.Fuzz(func(t *testing.T, levelInt int, msg string) {
+		// Use errorHandler (always enabled) to avoid level-based skipping
+		handlers := make([]*errorHandler, 3)
+		slogHandlers := make([]slog.Handler, 3)
+		for i := range handlers {
+			handlers[i] = &errorHandler{err: nil}
+			slogHandlers[i] = handlers[i]
+		}
+
+		pool := Pool()(slogHandlers...)
+
+		const iterations = 100
+		for i := 0; i < iterations; i++ {
+			r := buildFuzzRecord(levelInt, msg, 0)
+			err := pool.Handle(context.Background(), r)
+			assert.NoError(t, err)
+		}
+
+		var total int64
+		for _, h := range handlers {
+			total += h.handleCount.Load()
+		}
+		assert.Equal(t, int64(iterations), total)
+	})
+}
+
+func FuzzFirstMatchHandle(f *testing.F) {
+	f.Add(0, "hello world")
+	f.Add(4, "error occurred")
+	f.Add(-4, "debug")
+	f.Add(8, "")
+
+	f.Fuzz(func(t *testing.T, levelInt int, msg string) {
+		// Use errorHandler (always enabled) as sinks to avoid level gating
+		errorSink := &errorHandler{err: nil}
+		infoSink := &errorHandler{err: nil}
+		catchAll := &errorHandler{err: nil}
+
+		handler := Router().
+			Add(errorSink, LevelIs(slog.LevelError)).
+			Add(infoSink, LevelIs(slog.LevelInfo)).
+			Add(catchAll).
+			FirstMatch().
+			Handler()
+
+		r := buildFuzzRecord(levelInt, msg, 0)
+		err := handler.Handle(context.Background(), r)
+		assert.NoError(t, err)
+
+		level := slog.Level(levelInt)
+		total := errorSink.handleCount.Load() + infoSink.handleCount.Load() + catchAll.handleCount.Load()
+
+		switch level {
+		case slog.LevelError:
+			assert.Equal(t, int64(1), errorSink.handleCount.Load())
+			assert.Equal(t, int64(1), total)
+		case slog.LevelInfo:
+			assert.Equal(t, int64(1), infoSink.handleCount.Load())
+			assert.Equal(t, int64(1), total)
+		default:
+			// Catch-all gets it (no predicate, always matches)
+			assert.Equal(t, int64(1), catchAll.handleCount.Load())
+			assert.Equal(t, int64(1), total)
+		}
+	})
+}
+
+func FuzzRouterPredicates(f *testing.F) {
+	f.Add("hello world", 0)
+	f.Add("", -4)
+	f.Add("error in database", 8)
+	f.Add(strings.Repeat("x", 1000), 4)
+
+	f.Fuzz(func(t *testing.T, msg string, levelInt int) {
+		level := slog.Level(levelInt)
+		r := slog.NewRecord(time.Now(), level, msg, 0)
+		r.AddAttrs(slog.String("key", "value"), slog.Int("num", 42))
+		ctx := context.Background()
+
+		// All of these must not panic regardless of input
+		LevelIs(slog.LevelInfo, slog.LevelError)(ctx, r)
+		LevelIsNot(slog.LevelInfo)(ctx, r)
+		MessageIs(msg)(ctx, r)
+		MessageIsNot(msg)(ctx, r)
+		MessageContains("error")(ctx, r)
+		MessageNotContains("error")(ctx, r)
+		AttrValueIs("key", "value")(ctx, r)
+		AttrKindIs("key", slog.KindString)(ctx, r)
+	})
+}

go.mod

@@ -1,6 +1,6 @@
 module github.com/samber/slog-multi
 
-go 1.21
+go 1.22
 
 require (
 	github.com/samber/lo v1.52.0

go.work

@@ -1,4 +1,4 @@
-go 1.21
+go 1.22
 
 use (
 	.