Do not use fjson (#4175)

Closes #4157.

.golangci.yml

@@ -43,6 +43,8 @@ linters-settings:
       bson2:
         files:
           - $all
+          - "!**/internal/bson2/*_test.go"
+          - "!**/internal/util/testutil/*.go"
           - "!**/internal/wire/*.go"
         deny:
           - pkg: github.com/FerretDB/FerretDB/internal/bson2

integration/users/connection_test.go

@@ -361,11 +361,15 @@ func TestAuthenticationLocalhostException(tt *testing.T) {
 		{"mechanisms", bson.A{mechanism}},
 	}
 	err = db.RunCommand(ctx, secondUser).Err()
-	integration.AssertEqualCommandError(t, mongo.CommandError{
-		Code:    18,
-		Name:    "AuthenticationFailed",
-		Message: "Authentication failed",
-	}, err)
+	integration.AssertEqualCommandError(
+		t,
+		mongo.CommandError{
+			Code:    18,
+			Name:    "AuthenticationFailed",
+			Message: "Authentication failed",
+		},
+		err,
+	)
 
 	credential := options.Credential{
 		AuthMechanism: mechanism,

internal/bson/bson.go

@@ -65,42 +65,6 @@ type bsontype interface {
 	encoding.BinaryMarshaler
 }
 
-// TODO https://github.com/FerretDB/FerretDB/issues/260
-func fromBSON(v bsontype) any {
-	switch v := v.(type) {
-	case *Document:
-		return must.NotFail(types.ConvertDocument(v))
-	case *arrayType:
-		return pointer.To(types.Array(*v))
-	case *doubleType:
-		return float64(*v)
-	case *stringType:
-		return string(*v)
-	case *binaryType:
-		return types.Binary(*v)
-	case *objectIDType:
-		return types.ObjectID(*v)
-	case *boolType:
-		return bool(*v)
-	case *dateTimeType:
-		return time.Time(*v)
-	case *nullType:
-		return types.Null
-	case *regexType:
-		return types.Regex(*v)
-	case *int32Type:
-		return int32(*v)
-	case *timestampType:
-		return types.Timestamp(*v)
-	case *int64Type:
-		return int64(*v)
-	case *CString:
-		panic("CString should not be there")
-	}
-
-	panic(fmt.Sprintf("not reached: %T", v)) // for sumtype to work
-}
-
 // TODO https://github.com/FerretDB/FerretDB/issues/260
 //
 //nolint:deadcode,unused // remove later if it is not needed

internal/bson/bson_test.go

@@ -26,7 +26,6 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	"github.com/FerretDB/FerretDB/internal/types/fjson"
 	"github.com/FerretDB/FerretDB/internal/util/testutil/testtb"
 )
 
@@ -197,20 +196,6 @@ func fuzzBinary(f *testing.F, testCases []testCase, newFunc func() bsontype) {
 			require.NoError(t, err)
 			assert.Equal(t, expectedB, bw.Bytes(), "WriteTo results differ")
 		}
-
-		// Test that generated value can be marshaled for logging.
-		// Currently, that seems to be the best place to check it since generating values from BSON bytes is very easy.
-		{
-			// not a "real" type
-			if _, ok := v.(*CString); ok {
-				t.Skip()
-			}
-
-			// TODO https://github.com/FerretDB/FerretDB/issues/4157
-			mB, err := fjson.Marshal(fromBSON(v))
-			require.NoError(t, err)
-			assert.NotEmpty(t, mB)
-		}
 	})
 }
 

internal/bson2/array.go

@@ -144,18 +144,6 @@ func (arr *Array) LogValue() slog.Value {
 	return slogValue(arr, 1)
 }
 
-// LogMessage returns an indented representation as a string,
-// somewhat similar (but not identical) to JSON or Go syntax.
-// It may change over time.
-func (arr *Array) LogMessage() string {
-	return logMessage(arr, logMaxFlowLength, "", 1)
-}
-
-// LogMessageBlock is a variant of [Array.LogMessage] that never uses a flow style.
-func (arr *Array) LogMessageBlock() string {
-	return logMessage(arr, 0, "", 1)
-}
-
 // check interfaces
 var (
 	_ slog.LogValuer = (*Array)(nil)

internal/bson2/bson2.go

@@ -248,9 +248,15 @@ func convertToTypes(v any) (any, error) {
 	}
 }
 
-// convertFromTypes converts valid types package values to BSON values of that package.
+// Convert converts valid types package values to BSON values of that package.
 //
 // Conversions of composite types may cause errors.
+func Convert[T types.Type](v T) (any, error) {
+	return convertFromTypes(v)
+}
+
+// convertFromTypes is a variant of [Convert] without type parameters (generics).
+//
 // Invalid types cause panics.
 func convertFromTypes(v any) (any, error) {
 	switch v := v.(type) {