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chore: use math/rand/v2 instead of math/rand #7413

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4 changes: 2 additions & 2 deletions caddytest/integration/listener_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ package integration
import (
"bytes"
"fmt"
"math/rand"
"math/rand/v2"
"net"
"net/http"
"strings"
Expand Down Expand Up @@ -54,7 +54,7 @@ func TestHTTPRedirectWrapperWithLargeUpload(t *testing.T) {
const uploadSize = (1024 * 1024) + 1 // 1 MB + 1 byte
// 1 more than an MB
body := make([]byte, uploadSize)
rand.New(rand.NewSource(0)).Read(body)
rand.NewChaCha8([32]byte{}).Read(body)
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@diffray-bot diffray-bot Jan 2, 2026

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🟡 MEDIUM - Zero-initialized random seed produces deterministic test data
Agent: go

Category: quality

Description:
Using 'rand.NewChaCha8([32]byte{})' with a zero seed produces identical test data on every run. While this may be intentional for reproducibility, the test name suggests testing with varied data.

Suggestion:
If determinism is intended, add a comment explaining the choice. If varied data is desired, use a non-zero or time-based seed.

Confidence: 65%
Rule: qual_misleading_names_go
Review ID: 9bac5f9f-38e7-46a1-add2-7c064de630b1
Rate it 👍 or 👎 to improve future reviews | Powered by diffray


tester := setupListenerWrapperTest(t, func(writer http.ResponseWriter, request *http.Request) {
buf := new(bytes.Buffer)
Expand Down
4 changes: 2 additions & 2 deletions modules/caddyhttp/caddyauth/basicauth.go
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ import (
"encoding/hex"
"encoding/json"
"fmt"
weakrand "math/rand"
weakrand "math/rand/v2"
"net/http"
"strings"
"sync"
Expand Down Expand Up @@ -244,7 +244,7 @@ func (c *Cache) makeRoom() {
// strategy; generating random numbers is cheap and
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🔴 CRITICAL - Off-by-one error in cache eviction loop condition
Agent: go

Category: bug

Description:
Loop condition 'deleted <= numToDelete' causes deletion of numToDelete+1 items instead of numToDelete. With numToDelete=10, the loop runs for deleted values 0 through 10 inclusive (11 iterations), deleting 11 items instead of 10.

Suggestion:
Change '<=' to '<' on line 240: 'for deleted := 0; deleted < numToDelete; deleted++'

Confidence: 95%
Rule: bug_slice_bounds_go
Review ID: 9bac5f9f-38e7-46a1-add2-7c064de630b1
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// ensures a much better distribution.
//nolint:gosec
rnd := weakrand.Intn(len(c.cache))
rnd := weakrand.IntN(len(c.cache))
i := 0
for key := range c.cache {
if i == rnd {
Comment on lines +247 to 250
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🟠 HIGH - Inefficient O(n*m) cache eviction with repeated map traversals
Agent: go

Category: performance

Description:
The makeRoom() function performs numToDelete iterations, each generating a random index and iterating through the entire map to find and delete that element. This creates O(n*m) complexity where n is cache size and m is items to delete.

Suggestion:
Optimize by collecting all cache keys into a slice once, shuffling, and deleting the first numToDelete keys in a single pass for O(n) complexity.

Confidence: 85%
Rule: go_use_defer_to_release_resources
Review ID: 9bac5f9f-38e7-46a1-add2-7c064de630b1
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Expand Down
4 changes: 2 additions & 2 deletions modules/caddyhttp/errors.go
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@ package caddyhttp
import (
"errors"
"fmt"
weakrand "math/rand"
weakrand "math/rand/v2"
"path"
"runtime"
"strings"
Expand Down Expand Up @@ -98,7 +98,7 @@ func randString(n int, sameCase bool) string {
b := make([]byte, n)
for i := range b {
//nolint:gosec
b[i] = dict[weakrand.Int63()%int64(len(dict))]
b[i] = dict[weakrand.IntN(len(dict))]
}
return string(b)
}
Expand Down
4 changes: 2 additions & 2 deletions modules/caddyhttp/fileserver/staticfiles.go
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ import (
"fmt"
"io"
"io/fs"
weakrand "math/rand"
weakrand "math/rand/v2"
"mime"
"net/http"
"os"
Expand Down Expand Up @@ -601,7 +601,7 @@ func (fsrv *FileServer) openFile(fileSystem fs.FS, filename string, w http.Respo
// maybe the server is under load and ran out of file descriptors?
// have client wait arbitrary seconds to help prevent a stampede
//nolint:gosec
backoff := weakrand.Intn(maxBackoff-minBackoff) + minBackoff
backoff := weakrand.IntN(maxBackoff-minBackoff) + minBackoff
w.Header().Set("Retry-After", strconv.Itoa(backoff))
if c := fsrv.logger.Check(zapcore.DebugLevel, "retry after backoff"); c != nil {
c.Write(zap.String("filename", filename), zap.Int("backoff", backoff), zap.Error(err))
Expand Down
4 changes: 2 additions & 2 deletions modules/caddyhttp/reverseproxy/fastcgi/client_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ import (
"fmt"
"io"
"log"
"math/rand"
"math/rand/v2"
"net"
"net/http"
"net/http/fcgi"
Expand Down Expand Up @@ -197,7 +197,7 @@ func generateRandFile(size int) (p string, m string) {
h := md5.New()
for i := 0; i < size/16; i++ {
buf := make([]byte, 16)
binary.PutVarint(buf, rand.Int63())
binary.PutVarint(buf, rand.Int64())
if _, err := fo.Write(buf); err != nil {
log.Printf("[ERROR] failed to write buffer: %v\n", err)
}
Expand Down
4 changes: 2 additions & 2 deletions modules/caddyhttp/reverseproxy/httptransport.go
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,7 @@ import (
"encoding/base64"
"encoding/json"
"fmt"
weakrand "math/rand"
weakrand "math/rand/v2"
"net"
"net/http"
"net/url"
Expand Down Expand Up @@ -265,7 +265,7 @@ func (h *HTTPTransport) NewTransport(caddyCtx caddy.Context) (*http.Transport, e
PreferGo: true,
Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
//nolint:gosec
addr := h.Resolver.netAddrs[weakrand.Intn(len(h.Resolver.netAddrs))]
addr := h.Resolver.netAddrs[weakrand.IntN(len(h.Resolver.netAddrs))]
return d.DialContext(ctx, addr.Network, addr.JoinHostPort(0))
},
}
Expand Down
10 changes: 5 additions & 5 deletions modules/caddyhttp/reverseproxy/selectionpolicies.go
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ import (
"encoding/hex"
"encoding/json"
"fmt"
weakrand "math/rand"
weakrand "math/rand/v2"
"net"
"net/http"
"strconv"
Expand Down Expand Up @@ -225,7 +225,7 @@ func (r RandomChoiceSelection) Select(pool UpstreamPool, _ *http.Request, _ http
if !upstream.Available() {
continue
}
j := weakrand.Intn(i + 1) //nolint:gosec
j := weakrand.IntN(i + 1) //nolint:gosec
if j < k {
choices[j] = upstream
}
Expand Down Expand Up @@ -274,7 +274,7 @@ func (LeastConnSelection) Select(pool UpstreamPool, _ *http.Request, _ http.Resp
// sample: https://en.wikipedia.org/wiki/Reservoir_sampling
if numReqs == leastReqs {
count++
if count == 1 || (weakrand.Int()%count) == 0 { //nolint:gosec
if count == 1 || weakrand.IntN(count) == 0 { //nolint:gosec
bestHost = host
}
}
Expand Down Expand Up @@ -788,7 +788,7 @@ func selectRandomHost(pool []*Upstream) *Upstream {
// upstream will always be chosen if there is at
// least one available
count++
if (weakrand.Int() % count) == 0 { //nolint:gosec
if weakrand.IntN(count) == 0 { //nolint:gosec
randomHost = upstream
}
}
Expand Down Expand Up @@ -827,7 +827,7 @@ func leastRequests(upstreams []*Upstream) *Upstream {
if len(best) == 1 {
return best[0]
}
return best[weakrand.Intn(len(best))] //nolint:gosec
return best[weakrand.IntN(len(best))] //nolint:gosec
}

// hostByHashing returns an available host from pool based on a hashable string s.
Expand Down
2 changes: 1 addition & 1 deletion modules/caddyhttp/reverseproxy/streaming.go
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Expand Up @@ -24,7 +24,7 @@ import (
"errors"
"fmt"
"io"
weakrand "math/rand"
weakrand "math/rand/v2"
"mime"
"net/http"
"sync"
Expand Down
6 changes: 3 additions & 3 deletions modules/caddyhttp/reverseproxy/upstreams.go
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ import (
"context"
"encoding/json"
"fmt"
weakrand "math/rand"
weakrand "math/rand/v2"
"net"
"net/http"
"strconv"
Expand Down Expand Up @@ -102,7 +102,7 @@ func (su *SRVUpstreams) Provision(ctx caddy.Context) error {
PreferGo: true,
Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
//nolint:gosec
addr := su.Resolver.netAddrs[weakrand.Intn(len(su.Resolver.netAddrs))]
addr := su.Resolver.netAddrs[weakrand.IntN(len(su.Resolver.netAddrs))]
return d.DialContext(ctx, addr.Network, addr.JoinHostPort(0))
},
}
Expand Down Expand Up @@ -322,7 +322,7 @@ func (au *AUpstreams) Provision(ctx caddy.Context) error {
PreferGo: true,
Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
//nolint:gosec
addr := au.Resolver.netAddrs[weakrand.Intn(len(au.Resolver.netAddrs))]
addr := au.Resolver.netAddrs[weakrand.IntN(len(au.Resolver.netAddrs))]
return d.DialContext(ctx, addr.Network, addr.JoinHostPort(0))
},
}
Expand Down
4 changes: 2 additions & 2 deletions modules/caddypki/acmeserver/acmeserver.go
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Expand Up @@ -17,7 +17,7 @@ package acmeserver
import (
"context"
"fmt"
weakrand "math/rand"
weakrand "math/rand/v2"
"net"
"net/http"
"os"
Expand Down Expand Up @@ -307,7 +307,7 @@ func (ash Handler) makeClient() (acme.Client, error) {
PreferGo: true,
Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
//nolint:gosec
addr := ash.resolvers[weakrand.Intn(len(ash.resolvers))]
addr := ash.resolvers[weakrand.IntN(len(ash.resolvers))]
return dialer.DialContext(ctx, addr.Network, addr.JoinHostPort(0))
},
}
Expand Down
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