refactor: remove UnmarshalHandleDoubleEncode patch and fix repo unit TODO (#39998)

Remove the `UnmarshalHandleDoubleEncode` runtime workaround for an old
xorm bug, and normalize legacy double-encoded JSON in `repo_unit.config`
and `login_source.cfg` with a migration instead.

- Config `FromDB` no longer fails on corrupted values. A broken auth
source is deactivated, so admins can still fix it in the admin panel
- Remove `ProjectsConfig.GetProjectsMode`, `FromDB` already defaults
`ProjectsMode`

Actually it doesn't need so many changes, just because AI thinks it
should handle "corrupted database value" for auth sources.

---------

Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>

modules/json/json.go

@@ -5,7 +5,6 @@ package json
 
 import (
 	"bytes"
-	"encoding/binary"
 	"encoding/json" //nolint:depguard // this package wraps it
 	"io"
 )
@@ -81,38 +80,3 @@ func MarshalIndent(v any, prefix, indent string) ([]byte, error) {
 func Valid(data []byte) bool {
 	return json.Valid(data)
 }
-
-// UnmarshalHandleDoubleEncode - due to a bug in xorm (see https://gitea.com/xorm/xorm/pulls/1957) - it's
-// possible that a Blob may be double encoded or gain an unwanted prefix of 0xff 0xfe.
-func UnmarshalHandleDoubleEncode(bs []byte, v any) error {
-	if len(bs) == 0 {
-		// json.Unmarshal will report errors if input is empty (nil or zero-length)
-		// It seems that XORM ignores the nil but still passes zero-length string into this function
-		// To be consistent, we should treat all empty inputs as success
-		return nil
-	}
-	err := json.Unmarshal(bs, v)
-	if err != nil {
-		ok := true
-		rs := []byte{}
-		temp := make([]byte, 2)
-		for _, rn := range string(bs) {
-			if rn > 0xffff {
-				ok = false
-				break
-			}
-			binary.LittleEndian.PutUint16(temp, uint16(rn))
-			rs = append(rs, temp...)
-		}
-		if ok {
-			if len(rs) > 1 && rs[0] == 0xff && rs[1] == 0xfe {
-				rs = rs[2:]
-			}
-			err = json.Unmarshal(rs, v)
-		}
-	}
-	if err != nil && len(bs) > 2 && bs[0] == 0xff && bs[1] == 0xfe {
-		err = json.Unmarshal(bs[2:], v)
-	}
-	return err
-}

modules/json/json_test.go

@@ -10,14 +10,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestGiteaDBJSONUnmarshal(t *testing.T) {
-	var m map[any]any
-	err := UnmarshalHandleDoubleEncode(nil, &m)
-	assert.NoError(t, err)
-	err = UnmarshalHandleDoubleEncode([]byte(""), &m)
-	assert.NoError(t, err)
-}
-
 func TestIndent(t *testing.T) {
 	buf := &bytes.Buffer{}
 	err := Indent(buf, []byte(`{"a":1}`), ">", "  ")