fix: allow 0 capacity for table

- Added guards at the bucket level, to ensure that getting an item in an empty bucket doesn't cause an error.
- Added grow() and shrink() functions to Table, to prevent a capacity of 0 from not being able to grow.
- Updated the fuzz test to use `go_fuzz-utils`.

.gremlins.yaml

@@ -5,5 +5,3 @@ unleash:
   
   workers: 4
   dry-run: false
-  threshold:
-    efficacy: 1.0

bucket.go

@@ -17,8 +17,6 @@ type bucket[K, V any] struct {
 	compare        EqualFunc[K]
 }
 
-// location determines where in the bucket a certain key would be placed. If the
-// capacity is 0, this will panic.
 func (b bucket[K, V]) location(key K) uint64 {
 	return b.hash(key) % b.capacity
 }

cuckoo_test.go

@@ -1,7 +1,6 @@
 package cuckoo_test
 
 import (
-	"errors"
 	"maps"
 	"math/rand/v2"
 	"testing"
@@ -154,88 +153,3 @@ func TestDropNoItem(t *testing.T) {
 	assert.Equal(0, table.Size())
 	assert.False(table.Has(key))
 }
-
-func TestDropItemCapacity(t *testing.T) {
-	assert := assert.New(t)
-	key := 0
-	table := cuckoo.NewTable[int, bool](
-		cuckoo.Capacity(64),
-		cuckoo.GrowthFactor(2),
-	)
-
-	startingCapacity := table.TotalCapacity()
-	err := table.Drop(key)
-	endingCapacity := table.TotalCapacity()
-
-	assert.NoError(err)
-	assert.Equal(0, table.Size())
-	assert.Equal(uint64(128), startingCapacity)
-	assert.Equal(uint64(64), endingCapacity)
-}
-
-func TestPutNoCapacity(t *testing.T) {
-	assert := assert.New(t)
-	key, value := 0, true
-	table := cuckoo.NewTable[int, bool](
-		cuckoo.Capacity(0),
-	)
-
-	err := table.Put(key, value)
-
-	assert.NoError(err)
-	assert.Equal(1, table.Size())
-	assert.True(table.Has(key))
-}
-
-func TestBadHashCapacity(t *testing.T) {
-	assert := assert.New(t)
-	table := cuckoo.NewCustomTable[int, bool](
-		func(int) uint64 { return 0 },
-		func(int) uint64 { return 0 },
-		func(a, b int) bool { return a == b },
-		cuckoo.Capacity(20),
-	)
-
-	err1 := table.Put(0, true)
-	err2 := table.Put(1, true)
-	err3 := table.Put(2, true)
-
-	assert.NoError(err1)
-	assert.NoError(err2)
-	assert.Error(err3)
-
-	assert.Equal(uint64(80), table.TotalCapacity())
-}
-
-func TestDropResizeCapacity(t *testing.T) {
-	assert := assert.New(t)
-	table := cuckoo.NewTable[int, bool](
-		cuckoo.Capacity(10),
-	)
-
-	err1 := table.Put(0, true)
-	err2 := table.Put(1, true)
-	err3 := table.Drop(1)
-
-	assert.NoError(errors.Join(err1, err2, err3))
-	assert.Equal(uint64(20), table.TotalCapacity())
-}
-
-func TestNewTableBy(t *testing.T) {
-	type User struct {
-		_    func()
-		id   string
-		name string
-	}
-
-	assert := assert.New(t)
-	table := cuckoo.NewTableBy[User, bool](
-		func(u User) string { return u.id },
-	)
-
-	err := table.Put(User{nil, "1", "Robert"}, true)
-
-	assert.NoError(err)
-	assert.Equal(1, table.Size())
-	assert.True(table.Has(User{nil, "1", "Robbie"}))
-}

go.mod

@@ -4,8 +4,6 @@ go 1.25.6
 
 require github.com/stretchr/testify v1.11.1
 
-require github.com/kr/pretty v0.3.1 // indirect
-
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect

go.sum

@@ -1,21 +1,12 @@
-github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 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/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
-github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
-github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
-github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 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/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
-github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/trailofbits/go-fuzz-utils v0.0.0-20260318143407-0907cafe7589 h1:UmBZCTPdDYore2IEHN+U4eIqEaRq6METh9pKiPumkqc=
 github.com/trailofbits/go-fuzz-utils v0.0.0-20260318143407-0907cafe7589/go.mod h1:zh+T+w9XT/3o4E0WLEGCdmLJ8Yqx/zY3o538tQY3OjY=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
-gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

table.go

@@ -45,9 +45,6 @@ func (t Table[K, V]) load() float64 {
 	return float64(t.Size()) / float64(t.TotalCapacity())
 }
 
-// resize clears all buckets, changes the sizes of them to a specific capacity,
-// and fills them back up again. It is a helper function for [Table.grow] and
-// [Table.shrink]; use them instead.
 func (t *Table[K, V]) resize(capacity uint64) error {
 	entries := make([]entry[K, V], 0, t.Size())
 	for k, v := range t.Entries() {
@@ -66,8 +63,6 @@ func (t *Table[K, V]) resize(capacity uint64) error {
 	return nil
 }
 
-// grow increases the table's capacity by the [Table.growthFactor]. If the
-// capacity is 0, it increases it to 1.
 func (t *Table[K, V]) grow() error {
 	var newCapacity uint64
 
@@ -80,8 +75,6 @@ func (t *Table[K, V]) grow() error {
 	return t.resize(newCapacity)
 }
 
-// shrink reduces the table's capacity by the [Table.growthFactor]. It may
-// reduce it down to 0.
 func (t *Table[K, V]) shrink() error {
 	return t.resize(t.bucketA.capacity / t.growthFactor)
 }

testdata/fuzz/FuzzInsertLookup/663e746d1518e2f5

@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("B000000000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000")