style: apply gofmt to resolve lint errors

The doc comment on line 790 read:
  "BindXML is a shortcut for c.MustBindWith(obj, binding.BindXML)."

`binding.BindXML` does not exist. The correct symbol is `binding.XML`
(defined in binding/binding.go), which is also what the implementation
uses. All sibling methods (BindJSON, BindYAML, BindTOML, etc.) already
reference the correct symbol in their comments.

context.go

@@ -141,6 +141,16 @@ func (c *Context) Copy() *Context {
 	cp.Params = make([]Param, len(cParams))
 	copy(cp.Params, cParams)
 
+	if c.Errors != nil {
+		cp.Errors = make(errorMsgs, len(c.Errors))
+		copy(cp.Errors, c.Errors)
+	}
+
+	if c.Accepted != nil {
+		cp.Accepted = make([]string, len(c.Accepted))
+		copy(cp.Accepted, c.Accepted)
+	}
+
 	return &cp
 }
 
@@ -716,6 +726,11 @@ func (c *Context) MultipartForm() (*multipart.Form, error) {
 }
 
 // SaveUploadedFile uploads the form file to specific dst.
+// An optional perm argument specifies the permission bits used when creating
+// the destination directory. If not provided, the default is 0750. The exact
+// permission is enforced only on the destination directory and only when it is
+// newly created by this call; pre-existing directories (e.g. /tmp) are not
+// modified.
 func (c *Context) SaveUploadedFile(file *multipart.FileHeader, dst string, perm ...fs.FileMode) error {
 	src, err := file.Open()
 	if err != nil {
@@ -728,11 +743,19 @@ func (c *Context) SaveUploadedFile(file *multipart.FileHeader, dst string, perm
 		mode = perm[0]
 	}
 	dir := filepath.Dir(dst)
+	// Record whether the destination directory exists before MkdirAll, so we
+	// only chmod a directory we just created. Chmod'ing a pre-existing directory
+	// the process does not own (e.g. /tmp) fails with "operation not permitted"
+	// (#4622). A non-ErrNotExist stat error also skips chmod and lets MkdirAll
+	// surface the underlying failure.
+	_, statErr := os.Stat(dir)
 	if err = os.MkdirAll(dir, mode); err != nil {
 		return err
 	}
-	if err = os.Chmod(dir, mode); err != nil {
-		return err
+	if errors.Is(statErr, os.ErrNotExist) {
+		if err = os.Chmod(dir, mode); err != nil {
+			return err
+		}
 	}
 
 	out, err := os.Create(dst)
@@ -764,7 +787,7 @@ func (c *Context) BindJSON(obj any) error {
 	return c.MustBindWith(obj, binding.JSON)
 }
 
-// BindXML is a shortcut for c.MustBindWith(obj, binding.BindXML).
+// BindXML is a shortcut for c.MustBindWith(obj, binding.XML).
 func (c *Context) BindXML(obj any) error {
 	return c.MustBindWith(obj, binding.XML)
 }

context_test.go

@@ -248,13 +248,11 @@ func TestSaveUploadedFileWithPermission(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, "permission_test", f.Filename)
 	var mode fs.FileMode = 0o755
-	require.NoError(t, c.SaveUploadedFile(f, "permission_test", mode))
-	t.Cleanup(func() {
-		assert.NoError(t, os.Remove("permission_test"))
-	})
-	info, err := os.Stat(filepath.Dir("permission_test"))
+	dst := filepath.Join(t.TempDir(), "subdir", "permission_test")
+	require.NoError(t, c.SaveUploadedFile(f, dst, mode))
+	info, err := os.Stat(filepath.Dir(dst))
 	require.NoError(t, err)
-	assert.Equal(t, info.Mode().Perm(), mode)
+	assert.Equal(t, mode, info.Mode().Perm())
 }
 
 func TestSaveUploadedFileWithPermissionFailed(t *testing.T) {
@@ -272,7 +270,52 @@ func TestSaveUploadedFileWithPermissionFailed(t *testing.T) {
 	require.NoError(t, err)
 	assert.Equal(t, "permission_test", f.Filename)
 	var mode fs.FileMode = 0o644
-	require.Error(t, c.SaveUploadedFile(f, "test/permission_test", mode))
+	dst := filepath.Join(t.TempDir(), "test", "permission_test")
+	require.Error(t, c.SaveUploadedFile(f, dst, mode))
+}
+
+// TestSaveUploadedFileToExistingDir is a regression test for issue #4622.
+// SaveUploadedFile must not call os.Chmod on a directory that already exists,
+// because the process may not own it (e.g. /tmp on Linux/macOS), where chmod
+// fails with "operation not permitted". This asserts the behavioral contract
+// directly — a pre-existing directory's permissions are left unchanged — so it
+// catches the regression on every platform, including environments (root/CI,
+// user-owned $TMPDIR) where chmod on the temp dir would otherwise succeed.
+func TestSaveUploadedFileToExistingDir(t *testing.T) {
+	buf := new(bytes.Buffer)
+	mw := multipart.NewWriter(buf)
+	w, err := mw.CreateFormFile("file", "existing_dir_test")
+	require.NoError(t, err)
+	_, err = w.Write([]byte("existing_dir_test"))
+	require.NoError(t, err)
+	mw.Close()
+
+	c, _ := CreateTestContext(httptest.NewRecorder())
+	c.Request, _ = http.NewRequest(http.MethodPost, "/", buf)
+	c.Request.Header.Set("Content-Type", mw.FormDataContentType())
+	f, err := c.FormFile("file")
+	require.NoError(t, err)
+
+	// A pre-existing directory owned by this process, set to a known mode.
+	dir := t.TempDir()
+	require.NoError(t, os.Chmod(dir, 0o700))
+
+	// Pass a perm that differs from the directory's current mode. The fix must
+	// not apply it to the pre-existing directory; the old code chmod'd it
+	// unconditionally, which also failed outright on unowned dirs like /tmp.
+	dst := filepath.Join(dir, "existing_dir_test.txt")
+	require.NoError(t, c.SaveUploadedFile(f, dst, 0o755))
+
+	// The pre-existing directory's permissions must be unchanged.
+	info, err := os.Stat(dir)
+	require.NoError(t, err)
+	assert.Equal(t, os.FileMode(0o700), info.Mode().Perm(),
+		"permissions of a pre-existing directory must not be modified")
+
+	// The file must still be written with the correct content.
+	content, err := os.ReadFile(dst)
+	require.NoError(t, err)
+	assert.Equal(t, "existing_dir_test", string(content))
 }
 
 func TestContextReset(t *testing.T) {
@@ -689,6 +732,50 @@ func TestContextCopy(t *testing.T) {
 	assert.Equal(t, cp.fullPath, c.fullPath)
 }
 
+func TestContextCopyCopiesErrors(t *testing.T) {
+	c, _ := CreateTestContext(httptest.NewRecorder())
+	c.Request, _ = http.NewRequest(http.MethodGet, "/", nil)
+	_ = c.Error(errors.New("first error"))
+	_ = c.Error(errors.New("second error"))
+
+	cp := c.Copy()
+
+	// copied context has the same errors
+	assert.Len(t, cp.Errors, 2)
+	assert.Equal(t, c.Errors[0].Error(), cp.Errors[0].Error())
+	assert.Equal(t, c.Errors[1].Error(), cp.Errors[1].Error())
+
+	// mutations on the copy do not affect the original
+	_ = cp.Error(errors.New("third error"))
+	assert.Len(t, c.Errors, 2)
+	assert.Len(t, cp.Errors, 3)
+}
+
+func TestContextCopyCopiesAccepted(t *testing.T) {
+	c, _ := CreateTestContext(httptest.NewRecorder())
+	c.Request, _ = http.NewRequest(http.MethodGet, "/", nil)
+	c.SetAccepted("application/json", "text/html")
+
+	cp := c.Copy()
+
+	assert.Equal(t, c.Accepted, cp.Accepted)
+
+	// mutations on the copy do not affect the original
+	cp.SetAccepted("text/plain")
+	assert.Equal(t, []string{"application/json", "text/html"}, c.Accepted)
+	assert.Equal(t, []string{"text/plain"}, cp.Accepted)
+}
+
+func TestContextCopyNilErrorsAndAccepted(t *testing.T) {
+	c, _ := CreateTestContext(httptest.NewRecorder())
+	c.Request, _ = http.NewRequest(http.MethodGet, "/", nil)
+
+	cp := c.Copy()
+
+	assert.Nil(t, cp.Errors)
+	assert.Nil(t, cp.Accepted)
+}
+
 func TestContextHandlerName(t *testing.T) {
 	c, _ := CreateTestContext(httptest.NewRecorder())
 	c.handlers = HandlersChain{func(c *Context) {}, handlerNameTest}
@@ -3868,3 +3955,62 @@ func BenchmarkGetMapFromFormData(b *testing.B) {
 		})
 	}
 }
+
+func TestWildcardParamUnicodeConcurrency(t *testing.T) {
+	router := New()
+
+	var mu sync.Mutex
+	var errs []string
+
+	router.GET("/user/:name", func(c *Context) {
+		name := c.Param("name")
+		if name == "" {
+			mu.Lock()
+			errs = append(errs, "name param is empty")
+			mu.Unlock()
+		}
+	})
+
+	router.GET("/files/*filepath", func(c *Context) {
+		filepath := c.Param("filepath")
+		if filepath == "" {
+			mu.Lock()
+			errs = append(errs, "filepath param is empty")
+			mu.Unlock()
+		}
+	})
+
+	var wg sync.WaitGroup
+	paths := []string{
+		"/user/जयेश",
+		"/files/🎉/photo.png",
+		"/user/こんにちは",
+	}
+
+	for i := 0; i < 20; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for _, p := range paths {
+				req, err := http.NewRequest(http.MethodGet, p, nil)
+				if err != nil {
+					mu.Lock()
+					errs = append(errs, "failed to create request: "+err.Error())
+					mu.Unlock()
+					continue
+				}
+				w := httptest.NewRecorder()
+				router.ServeHTTP(w, req)
+
+				if w.Code != http.StatusOK {
+					mu.Lock()
+					errs = append(errs, "status code is not 200")
+					mu.Unlock()
+				}
+			}
+		}()
+	}
+	wg.Wait()
+
+	assert.Empty(t, errs)
+}

go.mod

@@ -5,14 +5,14 @@ go 1.25.0
 require (
 	github.com/bytedance/sonic v1.15.0
 	github.com/gin-contrib/sse v1.1.0
-	github.com/go-playground/validator/v10 v10.30.1
+	github.com/go-playground/validator/v10 v10.30.3
 	github.com/goccy/go-json v0.10.6
 	github.com/goccy/go-yaml v1.19.2
 	github.com/json-iterator/go v1.1.12
 	github.com/mattn/go-isatty v0.0.20
 	github.com/modern-go/reflect2 v1.0.2
 	github.com/pelletier/go-toml/v2 v2.2.4
-	github.com/quic-go/quic-go v0.59.0
+	github.com/quic-go/quic-go v0.60.0
 	github.com/stretchr/testify v1.11.1
 	github.com/ugorji/go/codec v1.3.1
 	go.mongodb.org/mongo-driver/v2 v2.5.0
@@ -39,7 +39,7 @@ require (
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	go.uber.org/mock v0.6.0 // indirect
 	golang.org/x/arch v0.25.0 // indirect
-	golang.org/x/crypto v0.51.0 // indirect
+	golang.org/x/crypto v0.52.0 // indirect
 	golang.org/x/sys v0.45.0 // indirect
 	golang.org/x/text v0.37.0 // indirect
 )

go.sum

@@ -20,8 +20,8 @@ github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/o
 github.com/go-playground/locales v0.14.1/go.mod h1:hxrqLVvrK65+Rwrd5Fc6F2O76J/NuW9t0sjnWqG1slY=
 github.com/go-playground/universal-translator v0.18.1 h1:Bcnm0ZwsGyWbCzImXv+pAJnYK9S473LQFuzCbDbfSFY=
 github.com/go-playground/universal-translator v0.18.1/go.mod h1:xekY+UJKNuX9WP91TpwSH2VMlDf28Uj24BCp08ZFTUY=
-github.com/go-playground/validator/v10 v10.30.1 h1:f3zDSN/zOma+w6+1Wswgd9fLkdwy06ntQJp0BBvFG0w=
-github.com/go-playground/validator/v10 v10.30.1/go.mod h1:oSuBIQzuJxL//3MelwSLD5hc2Tu889bF0Idm9Dg26cM=
+github.com/go-playground/validator/v10 v10.30.3 h1:4MU6YkEwx7GbcPJOZxrtbu+QfF3pJLJuaYTeAH0DYy8=
+github.com/go-playground/validator/v10 v10.30.3/go.mod h1:4Axh7oCNGcoGkqLoE4YWt6n20mcEIsPRlB7vPk3lpyc=
 github.com/goccy/go-json v0.10.6 h1:p8HrPJzOakx/mn/bQtjgNjdTcN+/S6FcG2CTtQOrHVU=
 github.com/goccy/go-json v0.10.6/go.mod h1:oq7eo15ShAhp70Anwd5lgX2pLfOS3QCiwU/PULtXL6M=
 github.com/goccy/go-yaml v1.19.2 h1:PmFC1S6h8ljIz6gMRBopkjP1TVT7xuwrButHID66PoM=
@@ -50,10 +50,12 @@ github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0
 github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
 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/quic-go/go-ossfuzz-seeds v0.1.0 h1:APacT+iIaNF6fd8AGEiN3bT/Jtkd2jz4v4TzM7MFjy0=
+github.com/quic-go/go-ossfuzz-seeds v0.1.0/go.mod h1:3IOHRbJIc+L6YKMwfDtJAM9Vj9k0YY4muhuyUYk5tbk=
 github.com/quic-go/qpack v0.6.0 h1:g7W+BMYynC1LbYLSqRt8PBg5Tgwxn214ZZR34VIOjz8=
 github.com/quic-go/qpack v0.6.0/go.mod h1:lUpLKChi8njB4ty2bFLX2x4gzDqXwUpaO1DP9qMDZII=
-github.com/quic-go/quic-go v0.59.0 h1:OLJkp1Mlm/aS7dpKgTc6cnpynnD2Xg7C1pwL6vy/SAw=
-github.com/quic-go/quic-go v0.59.0/go.mod h1:upnsH4Ju1YkqpLXC305eW3yDZ4NfnNbmQRCMWS58IKU=
+github.com/quic-go/quic-go v0.60.0 h1:xcQioE8OM66UQLeUMHltK1CCcOu3JbVB4JAQdDQSB+0=
+github.com/quic-go/quic-go v0.60.0/go.mod h1:wpKpjmPpftl30sL6pFh7REVpjbcCVy4zt2vDyK1TuJk=
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
 github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -77,8 +79,8 @@ go.uber.org/mock v0.6.0 h1:hyF9dfmbgIX5EfOdasqLsWD6xqpNZlXblLB/Dbnwv3Y=
 go.uber.org/mock v0.6.0/go.mod h1:KiVJ4BqZJaMj4svdfmHM0AUx4NJYO8ZNpPnZn1Z+BBU=
 golang.org/x/arch v0.25.0 h1:qnk6Ksugpi5Bz32947rkUgDt9/s5qvqDPl/gBKdMJLE=
 golang.org/x/arch v0.25.0/go.mod h1:0X+GdSIP+kL5wPmpK7sdkEVTt2XoYP0cSjQSbZBwOi8=
-golang.org/x/crypto v0.51.0 h1:IBPXwPfKxY7cWQZ38ZCIRPI50YLeevDLlLnyC5wRGTI=
-golang.org/x/crypto v0.51.0/go.mod h1:8AdwkbraGNABw2kOX6YFPs3WM22XqI4EXEd8g+x7Oc8=
+golang.org/x/crypto v0.52.0 h1:RMs7fP2rXdep0CftQlK8Uf+kibLm7qkCcradZWYz988=
+golang.org/x/crypto v0.52.0/go.mod h1:1QgfPxDqh0T2M/elOJtp9RvuR95kVjir0e6/BvEmGbc=
 golang.org/x/net v0.55.0 h1:bcvxaJn3e1U6InsFWt1JUq1aSjnRxLzT2rtD2KfkDF8=
 golang.org/x/net v0.55.0/go.mod h1:L5U2KuzuOe1lY7Z+aWVIKK6qEeJXnXV9yzGA+WCHJww=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

recovery.go

@@ -106,7 +106,12 @@ func secureRequestDump(r *http.Request) string {
 	return strings.Join(lines, "\r\n")
 }
 
-func defaultHandleRecovery(c *Context, _ any) {
+func defaultHandleRecovery(c *Context, err any) {
+	e, ok := err.(error)
+	if !ok {
+		e = fmt.Errorf("%v", err)
+	}
+	c.Error(e) //nolint: errcheck
 	c.AbortWithStatus(http.StatusInternalServerError)
 }
 

recovery_test.go

@@ -5,6 +5,7 @@
 package gin
 
 import (
+	"errors"
 	"net"
 	"net/http"
 	"os"
@@ -152,6 +153,49 @@ func TestPanicWithAbortHandler(t *testing.T) {
 	assert.NotContains(t, out, "panic recovered")
 }
 
+func TestPanicInHandlerRecordsError(t *testing.T) {
+	tests := []struct {
+		name         string
+		recoveredErr any
+		expectedErr  string
+	}{
+		{
+			name:         "string panic",
+			recoveredErr: "Oops, Houston, we have a problem",
+			expectedErr:  "Oops, Houston, we have a problem",
+		},
+		{
+			name:         "error panic",
+			recoveredErr: errors.New("recovered error"),
+			expectedErr:  "recovered error",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			router := New()
+
+			var recoveredErrors errorMsgs
+			router.Use(func(c *Context) {
+				c.Next()
+				recoveredErrors = c.Errors
+			})
+			router.Use(RecoveryWithWriter(nil))
+			router.GET("/recovery", func(_ *Context) {
+				panic(tt.recoveredErr)
+			})
+
+			w := PerformRequest(router, http.MethodGet, "/recovery")
+
+			assert.Equal(t, http.StatusInternalServerError, w.Code)
+			if assert.Len(t, recoveredErrors, 1) {
+				assert.EqualError(t, recoveredErrors[0], tt.expectedErr)
+				assert.Equal(t, ErrorTypePrivate, recoveredErrors[0].Type)
+			}
+		})
+	}
+}
+
 func TestCustomRecoveryWithWriter(t *testing.T) {
 	errBuffer := new(strings.Builder)
 	buffer := new(strings.Builder)

response_writer_test.go

@@ -15,10 +15,33 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// TODO
-// func (w *responseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-// func (w *responseWriter) CloseNotify() <-chan bool {
-// func (w *responseWriter) Flush() {
+// TestResponseWriterFlushWithFlusher verifies Flush() calls the underlying Flusher.
+func TestResponseWriterFlushWithFlusher(t *testing.T) {
+	testWriter := httptest.NewRecorder()
+	writer := &responseWriter{ResponseWriter: testWriter}
+	writer.Flush()
+	assert.True(t, testWriter.Flushed)
+}
+
+// TestResponseWriterFlushWithNonFlusher verifies Flush() is a no-op
+// when the underlying ResponseWriter does not implement http.Flusher.
+// Guards against the panic reported in https://github.com/gin-gonic/gin/issues/4460
+func TestResponseWriterFlushWithNonFlusher(t *testing.T) {
+	nonFlusher := &nonFlusherWriter{header: http.Header{}}
+	writer := &responseWriter{ResponseWriter: nonFlusher}
+	require.NotPanics(t, func() {
+		writer.Flush()
+	})
+}
+
+// nonFlusherWriter is a minimal http.ResponseWriter that does NOT implement http.Flusher.
+type nonFlusherWriter struct {
+	header http.Header
+}
+
+func (w *nonFlusherWriter) Header() http.Header         { return w.header }
+func (w *nonFlusherWriter) Write(b []byte) (int, error) { return len(b), nil }
+func (w *nonFlusherWriter) WriteHeader(code int)        {}
 
 var (
 	_ ResponseWriter      = &responseWriter{}

tree.go

@@ -509,6 +509,11 @@ walk: // Outer loop for walking the tree
 						// Expand slice within preallocated capacity
 						i := len(*value.params)
 						*value.params = (*value.params)[:i+1]
+
+						// Ensure 'end' index lands exactly on a valid UTF-8 rune boundary
+						for end > 0 && end < len(path) && !utf8.RuneStart(path[end]) {
+							end--
+						}
 						val := path[:end]
 						if unescape {
 							if v, err := url.QueryUnescape(val); err == nil {

tree_test.go

@@ -1111,3 +1111,20 @@ func TestTreeFindCaseInsensitivePathWildcardParamAndStaticChild(t *testing.T) {
 		t.Errorf("Wrong result for '/prefix/something': %s", string(out))
 	}
 }
+
+func TestTreeWildcardParamImproperBoundaryCoverage(t *testing.T) {
+	tree := &node{}
+
+	// Register a path with a wild named parameter segment
+	tree.addRoute("/submit/:info", HandlersChain{func(c *Context) {}})
+
+	// Pass a path containing a multi-byte sequence where a standard byte segment lookup
+	// drifts directly into the middle of a continuation block.
+	// This exercises our inner boundary alignment decrement loop.
+	path := "/submit/जय"
+	value := tree.getValue(path, &Params{}, nil, false)
+
+	if value.handlers == nil {
+		t.Errorf("Routing fallback failed on multi-byte parameter verification evaluation.")
+	}
+}