Chore: Replace lithammer/shortuuid with custom shortuuid implementation and update tests

.github/workflows/tests.yml

@@ -31,7 +31,7 @@ jobs:
       # https://olegk.dev/github-actions-and-go
       run: gofmt -s -w . && git diff --exit-code
     - name: Run Go tests
-      run: go test -p 1 ./internal/storage ./server ./internal/smtpd ./internal/pop3 ./internal/tools ./internal/html2text ./internal/htmlcheck ./internal/linkcheck -v
+      run: go test -p 1 ./internal/storage ./server ./internal/smtpd ./internal/pop3 ./internal/tools ./internal/html2text ./internal/htmlcheck ./internal/linkcheck ./internal/shortuuid -v
     - name: Run Go benchmarking
       run: go test -p 1 ./internal/storage ./internal/html2text -bench=.
     

go.mod

@@ -9,12 +9,12 @@ require (
 	github.com/axllent/semver v1.0.0
 	github.com/goccy/go-yaml v1.19.2
 	github.com/gomarkdown/markdown v0.0.0-20260412113850-134a5b2cce7f
+	github.com/google/uuid v1.6.0
 	github.com/gorilla/websocket v1.5.3
 	github.com/jhillyerd/enmime/v2 v2.3.0
 	github.com/klauspost/compress v1.18.5
 	github.com/kovidgoyal/imaging v1.8.21
 	github.com/leporo/sqlf v1.4.0
-	github.com/lithammer/shortuuid/v4 v4.2.0
 	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.23.2
 	github.com/rqlite/gorqlite v0.0.0-20250609141355-ac86a4a1c9a8
@@ -41,7 +41,6 @@ require (
 	github.com/fatih/color v1.19.0 // indirect
 	github.com/goccy/go-json v0.10.6 // indirect
 	github.com/gogs/chardet v0.0.0-20211120154057-b7413eaefb8f // indirect
-	github.com/google/uuid v1.6.0 // indirect
 	github.com/gorilla/css v1.0.1 // indirect
 	github.com/inbucket/html2text v1.0.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect

go.sum

@@ -69,8 +69,6 @@ github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/leporo/sqlf v1.4.0 h1:SyWnX/8GSGOzVmanG0Ub1c04mR9nNl6Tq3IeFKX2/4c=
 github.com/leporo/sqlf v1.4.0/go.mod h1:pgN9yKsAnQ+2ewhbZogr98RcasUjPsHF3oXwPPhHvBw=
-github.com/lithammer/shortuuid/v4 v4.2.0 h1:LMFOzVB3996a7b8aBuEXxqOBflbfPQAiVzkIcHO0h8c=
-github.com/lithammer/shortuuid/v4 v4.2.0/go.mod h1:D5noHZ2oFw/YaKCfGy0YxyE7M0wMbezmMjPdhyEFe6Y=
 github.com/mattn/go-colorable v0.1.14 h1:9A9LHSqF/7dyVVX6g0U9cwm9pG3kP9gSzcuIPHPsaIE=
 github.com/mattn/go-colorable v0.1.14/go.mod h1:6LmQG8QLFO4G5z1gPvYEzlUgJ2wF+stgPZH1UqBm1s8=
 github.com/mattn/go-isatty v0.0.21 h1:xYae+lCNBP7QuW4PUnNG61ffM4hVIfm+zUzDuSzYLGs=

internal/shortuuid/shortuuid.go

@@ -0,0 +1,53 @@
+// Package shortuuid provides a simple way to generate short, unique, alphanumeric identifiers.
+// The generated IDs are 22 characters long and consist of uppercase letters, lowercase letters, and digits.
+package shortuuid
+
+import (
+	"encoding/binary"
+	"math/bits"
+
+	"github.com/google/uuid"
+)
+
+const (
+	alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+	length   = 22
+	nDigits  = 10
+	divisor  = 839299365868340224 // 62^10, max power of 62 that fits in uint64
+)
+
+// New returns a 22-character alphanumeric unique identifier.
+func New() string {
+	id := uuid.New()
+	num := [2]uint64{
+		binary.BigEndian.Uint64(id[8:]),
+		binary.BigEndian.Uint64(id[:8]),
+	}
+
+	buf := make([]byte, length)
+	var r uint64
+	i := length - 1
+	for num[1] > 0 || num[0] > 0 {
+		num, r = quoRem64(num, divisor)
+		for j := 0; j < nDigits && i >= 0; j++ {
+			buf[i] = alphabet[r%62]
+			r /= 62
+			i--
+		}
+	}
+	for ; i >= 0; i-- {
+		buf[i] = alphabet[0]
+	}
+
+	return string(buf)
+}
+
+// quoRem64 divides a 128-bit number (represented as [lo, hi] uint64) by v,
+// returning the quotient and remainder.
+func quoRem64(u [2]uint64, v uint64) ([2]uint64, uint64) {
+	var q [2]uint64
+	var r uint64
+	q[1], r = bits.Div64(0, u[1], v)
+	q[0], r = bits.Div64(r, u[0], v)
+	return q, r
+}

internal/shortuuid/shortuuid_test.go

@@ -0,0 +1,52 @@
+package shortuuid
+
+import (
+	"regexp"
+	"testing"
+)
+
+// alphanumeric matches IDs that contain only digits and ASCII letters.
+var alphanumeric = regexp.MustCompile(`^[0-9A-Za-z]+$`)
+
+// TestLength verifies that every generated ID is exactly 22 characters long,
+// including when the UUID encodes to a value with leading zero-padding.
+func TestLength(t *testing.T) {
+	for range 100 {
+		id := New()
+		if len(id) != length {
+			t.Errorf("expected length %d, got %d: %q", length, len(id), id)
+		}
+	}
+}
+
+// TestAlphanumeric verifies that no ID contains hyphens, underscores, or any
+// other non-alphanumeric character that would be unsafe in a URL path segment.
+func TestAlphanumeric(t *testing.T) {
+	for range 100 {
+		id := New()
+		if !alphanumeric.MatchString(id) {
+			t.Errorf("non-alphanumeric characters in ID: %q", id)
+		}
+	}
+}
+
+// TestUnique verifies that IDs are unique across a large sample. Collisions are
+// cryptographically implausible given the 122-bit UUID entropy, so any hit here
+// indicates a bug in the encoding (e.g. truncation, constant output).
+func TestUnique(t *testing.T) {
+	seen := make(map[string]struct{}, 1000000)
+	for range 1000000 {
+		id := New()
+		if _, exists := seen[id]; exists {
+			t.Fatalf("duplicate ID generated: %q", id)
+		}
+		seen[id] = struct{}{}
+	}
+}
+
+// BenchmarkNew measures the cost of generating a single ID, including UUID generation.
+func BenchmarkNew(b *testing.B) {
+	for b.Loop() {
+		_ = New()
+	}
+}

internal/smtpd/main.go

@@ -12,11 +12,11 @@ import (
 	"github.com/axllent/mailpit/config"
 	"github.com/axllent/mailpit/internal/auth"
 	"github.com/axllent/mailpit/internal/logger"
+	"github.com/axllent/mailpit/internal/shortuuid"
 	"github.com/axllent/mailpit/internal/stats"
 	"github.com/axllent/mailpit/internal/storage"
 	"github.com/axllent/mailpit/internal/tools"
 	"github.com/axllent/mailpit/server/websockets"
-	"github.com/lithammer/shortuuid/v4"
 	"github.com/pkg/errors"
 )
 

internal/storage/messages.go

@@ -19,12 +19,12 @@ import (
 
 	"github.com/axllent/mailpit/config"
 	"github.com/axllent/mailpit/internal/logger"
+	"github.com/axllent/mailpit/internal/shortuuid"
 	"github.com/axllent/mailpit/internal/tools"
 	"github.com/axllent/mailpit/server/webhook"
 	"github.com/axllent/mailpit/server/websockets"
 	"github.com/jhillyerd/enmime/v2"
 	"github.com/leporo/sqlf"
-	"github.com/lithammer/shortuuid/v4"
 )
 
 // Store will save an email to the database tables.

server/apiv1/release.go

@@ -10,10 +10,10 @@ import (
 
 	"github.com/axllent/mailpit/config"
 	"github.com/axllent/mailpit/internal/logger"
+	"github.com/axllent/mailpit/internal/shortuuid"
 	"github.com/axllent/mailpit/internal/smtpd"
 	"github.com/axllent/mailpit/internal/storage"
 	"github.com/axllent/mailpit/internal/tools"
-	"github.com/lithammer/shortuuid/v4"
 )
 
 // ReleaseMessage (method: POST) will release a message via a pre-configured external SMTP server.

server/server.go

@@ -21,6 +21,7 @@ import (
 	"github.com/axllent/mailpit/internal/logger"
 	"github.com/axllent/mailpit/internal/pop3"
 	"github.com/axllent/mailpit/internal/prometheus"
+	"github.com/axllent/mailpit/internal/shortuuid"
 	"github.com/axllent/mailpit/internal/snakeoil"
 	"github.com/axllent/mailpit/internal/stats"
 	"github.com/axllent/mailpit/internal/storage"
@@ -28,7 +29,6 @@ import (
 	"github.com/axllent/mailpit/server/apiv1"
 	"github.com/axllent/mailpit/server/handlers"
 	"github.com/axllent/mailpit/server/websockets"
-	"github.com/lithammer/shortuuid/v4"
 )
 
 var (