Alternate fix for #846, with concatenated errors

common/http/http.go

@@ -39,7 +39,14 @@ func PostJSON(
 
 	res, err := httpClient.Do(req.WithContext(ctx))
 	if res != nil {
-		defer (func() { err = res.Body.Close() })()
+		defer (func() {
+			finalErr := res.Body.Close()
+			if err != nil && finalErr != nil {
+				err = fmt.Errorf("%s\n%s", err, finalErr)
+			} else if err == nil {
+				err = finalErr
+			}
+		})()
 	}
 	if err != nil {
 		return err

common/test/client.go

@@ -82,7 +82,14 @@ func (r *Request) Do() (err error) {
 	if err != nil {
 		return err
 	}
-	defer (func() { err = res.Body.Close() })()
+	defer (func() {
+		finalErr := res.Body.Close()
+		if err != nil && finalErr != nil {
+			err = fmt.Errorf("%s\n%s", err, finalErr)
+		} else if err == nil {
+			err = finalErr
+		}
+	})()
 
 	if res.StatusCode != r.WantedStatusCode {
 		return fmt.Errorf("incorrect status code. Expected: %d  Got: %d", r.WantedStatusCode, res.StatusCode)

mediaapi/fileutils/fileutils.go

@@ -112,8 +112,14 @@ func WriteTempFile(reqReader io.Reader, maxFileSizeBytes config.FileSizeBytes, a
 	if err != nil {
 		return
 	}
-	defer (func() { err = tmpFile.Close() })()
-
+	defer (func() {
+		finalErr := tmpFile.Close()
+		if err != nil && finalErr != nil {
+			err = fmt.Errorf("%s\n%s", err, finalErr)
+		} else if err == nil {
+			err = finalErr
+		}
+	})()
 	// The amount of data read is limited to maxFileSizeBytes. At this point, if there is more data it will be truncated.
 	limitedReader := io.LimitReader(reqReader, int64(maxFileSizeBytes))
 	// Hash the file data. The hash will be returned. The hash is useful as a

mediaapi/thumbnailer/thumbnailer_nfnt.go

@@ -18,6 +18,7 @@ package thumbnailer
 
 import (
 	"context"
+	"fmt"
 	"image"
 	"image/draw"
 
@@ -125,7 +126,14 @@ func writeFile(img image.Image, dst string) (err error) {
 	if err != nil {
 		return err
 	}
-	defer (func() { err = out.Close() })()
+	defer (func() {
+		finalErr := out.Close()
+		if err != nil && finalErr != nil {
+			err = fmt.Errorf("%s\n%s", err, finalErr)
+		} else if err == nil {
+			err = finalErr
+		}
+	})()
 
 	return jpeg.Encode(out, img, &jpeg.Options{
 		Quality: 85,

roomserver/storage/invite_table.go

@@ -17,6 +17,7 @@ package storage
 import (
 	"context"
 	"database/sql"
+	"fmt"
 
 	"github.com/matrix-org/dendrite/common"
 	"github.com/matrix-org/dendrite/roomserver/types"
@@ -119,7 +120,14 @@ func (s *inviteStatements) updateInviteRetired(
 	if err != nil {
 		return nil, err
 	}
-	defer (func() { err = rows.Close() })()
+	defer (func() {
+		finalErr := rows.Close()
+		if err != nil && finalErr != nil {
+			err = fmt.Errorf("%s\n%s", err, finalErr)
+		} else if err == nil {
+			err = finalErr
+		}
+	})()
 	for rows.Next() {
 		var inviteEventID string
 		if err := rows.Scan(&inviteEventID); err != nil {