Handle PNG named *.webp

Fixes #14288

diff --git a/resources/images/codec.go b/resources/images/codec.go
index 2bd93b579c3f548748a522efe2a5c239fa927070..7fe1ccf5bfdc79e5ab8892d1782d56526a7889b2 100644 (file)
--- a/resources/images/codec.go
+++ b/resources/images/codec.go
@@ -132,7 +132,7 @@ func (d *Codec) EncodeTo(conf ImageConfig, w io.Writer, img image.Image) error {
 func (d *Codec) DecodeFormat(f Format, r io.Reader) (image.Image, error) {
        switch f {
        case JPEG, PNG:
-               // TODO(bep) we reworked this decode/encode setup to get full WebP support in v0.153.0.
+               // We reworked this decode/encode setup to get full WebP support in v0.153.0.
                // In the first take of that we used f to decide whether to call png.Decode or jpeg.Decode here,
                // but testing it on some sites, it seems that it's not uncommon to store JPEGs with PNG extensions and vice versa.
                // So, to reduce some noise in that release, we fallback to the standard library here,
@@ -153,7 +153,25 @@ func (d *Codec) DecodeFormat(f Format, r io.Reader) (image.Image, error) {
        case BMP:
                return bmp.Decode(r)
        case WEBP:
-               return d.webp.Decode(r)
+               img, err := d.webp.Decode(r)
+               if err == nil {
+                       return img, nil
+               }
+               if rs, ok := r.(io.ReadSeeker); ok {
+                       // See issue 14288. Turns out it's not uncommon to e.g. name their PNG files with a WEBP extension.
+                       // With the old Go's webp decoder, this didn't fail (it looked for the file header),
+                       // but now some error has surfaced.
+                       // To reduce some noise, we try to reset and decode again using the standard library.
+                       _, err2 := rs.Seek(0, io.SeekStart)
+                       if err2 != nil {
+                               return nil, err
+                       }
+                       img, _, err2 = image.Decode(rs)
+                       if err2 == nil {
+                               return img, nil
+                       }
+               }
+               return nil, err
        default:
                return nil, errors.New("format not supported")
        }

diff --git a/tpl/images/images_integration_test.go b/tpl/images/images_integration_test.go
index c6226f611a8e08924aa69e80eb8c094b67a10409..b8edb22f3a7c7e6e78f5d4a3e835638b6a22608f 100644 (file)
--- a/tpl/images/images_integration_test.go
+++ b/tpl/images/images_integration_test.go
@@ -165,3 +165,26 @@ Brightnes method: /qr_hu_d5f06fd7594d0594.png
 Brightnes func: /qr_hu_d5f06fd7594d0594.png
 `)
 }
+
+func TestPNGNamedWebpIssue14288(t *testing.T) {
+       t.Parallel()
+
+       files := `
+-- assets/qr.webp --
+sourcefilename: testdata/images_golden/funcs/qr-level-high_scale-6.png
+-- layouts/home.html --
+{{ $img := resources.Get "qr.webp" }}
+images.Config: {{ (images.Config "assets/qr.webp").Width }}
+Resize to 100x100: {{ ($img.Resize "100x100" ).Width }}
+Brightnes method: {{ ($img.Filter (images.Brightness 12) ).RelPermalink }}
+Brightnes func: {{ ($img | images.Filter (images.Brightness 12) ).RelPermalink }}
+`
+
+       b := hugolib.Test(t, files)
+       b.AssertFileContent("public/index.html", `
+images.Config: 222
+Resize to 100x100: 100
+Brightnes method: /qr_hu_d5f06fd7594d0594.webp
+Brightnes func: /qr_hu_d5f06fd7594d0594.webp
+`)
+}