Fix so temporary images do not get published

Fixes #10255

3 files changed, 65 insertions, 49 deletions

diff --git a/resources/image_cache.go b/resources/image_cache.go
index 636607f94..542a6836f 100644
--- a/resources/image_cache.go
+++ b/resources/image_cache.go
@@ -106,28 +106,10 @@ func (c *ImageCache) getOrCreate(
 		rp := img.getResourcePaths()
 		rp.relTargetDirFile.file = relTarget.file
 		img.setSourceFilename(info.Name)
+		img.setSourfeFilenameIsHash(true)
 		img.setMediaType(conf.TargetFormat.MediaType())
 
-		if err := img.InitConfig(r); err != nil {
-			return err
-		}
-
-		r.Seek(0, 0)
-
-		w, err := img.openDestinationsForWriting()
-		if err != nil {
-			return err
-		}
-
-		if w == nil {
-			// Nothing to write.
-			return nil
-		}
-
-		defer w.Close()
-		_, err = io.Copy(w, r)
-
-		return err
+		return img.InitConfig(r)
 	}
 
 	// create creates the image and encodes it to the cache (w).
diff --git a/resources/integration_test.go b/resources/integration_test.go
index 543c264dc..2075079dc 100644
--- a/resources/integration_test.go
+++ b/resources/integration_test.go
@@ -100,3 +100,42 @@ Width: {{ $svg.Width }}
 	b.Assert(err.Error(), qt.Contains, `error calling Width: this method is only available for raster images. To determine if an image is SVG, you can do {{ if eq .MediaType.SubType "svg" }}{{ end }}`)
 
 }
+
+// Issue 10255.
+func TestNoPublishOfUnusedProcessedImage(t *testing.T) {
+	t.Parallel()
+
+	workingDir := t.TempDir()
+
+	files := `
+-- assets/images/pixel.png --
+iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==
+-- layouts/index.html --
+{{ $image := resources.Get "images/pixel.png" }}
+{{ $image = $image.Resize "400x" }}
+{{ $image = $image.Resize "300x" }}
+{{ $image = $image.Resize "200x" }}
+{{ $image = $image.Resize "100x" }}
+{{ $image = $image.Crop "50x50" }}
+{{ $image = $image.Filter (images.GaussianBlur 6) }}
+{{ ($image | fingerprint).Permalink }}
+
+
+`
+
+	for i := 0; i < 3; i++ {
+
+		b := hugolib.NewIntegrationTestBuilder(
+			hugolib.IntegrationTestConfig{
+				T:           t,
+				TxtarString: files,
+				NeedsOsFS:   true,
+				WorkingDir:  workingDir,
+			}).Build()
+
+		b.AssertFileCount("resources/_gen/images", 6)
+		b.AssertFileCount("public/images", 1)
+		b.Build()
+	}
+
+}
diff --git a/resources/resource.go b/resources/resource.go
index d1acc1026..884900d58 100644
--- a/resources/resource.go
+++ b/resources/resource.go
@@ -161,7 +161,6 @@ type baseResourceInternal interface {
 	specProvider
 	getResourcePaths() *resourcePathDescriptor
 	getTargetFilenames() []string
-	openDestinationsForWriting() (io.WriteCloser, error)
 	openPublishFileForWriting(relTargetPath string) (io.WriteCloser, error)
 
 	relTargetPathForRel(rel string, addBaseTargetPath, isAbs, isURL bool) string
@@ -216,6 +215,7 @@ func (d dirFile) path() string {
 type fileInfo interface {
 	getSourceFilename() string
 	setSourceFilename(string)
+	setSourfeFilenameIsHash(bool)
 	setSourceFs(afero.Fs)
 	getFileInfo() hugofs.FileMetaInfo
 	hash() (string, error)
@@ -304,6 +304,21 @@ func (l *genericResource) Permalink() string {
 func (l *genericResource) Publish() error {
 	var err error
 	l.publishInit.Do(func() {
+		targetFilenames := l.getTargetFilenames()
+		if l.sourceFilenameIsHash {
+			// This is a processed image. We want to avoid copying it if it hasn't changed.
+			var changedFilenames []string
+			for _, targetFilename := range targetFilenames {
+				if _, err := l.getSpec().BaseFs.PublishFs.Stat(targetFilename); err == nil {
+					continue
+				}
+				changedFilenames = append(changedFilenames, targetFilename)
+			}
+			if len(changedFilenames) == 0 {
+				return
+			}
+			targetFilenames = changedFilenames
+		}
 		var fr hugio.ReadSeekCloser
 		fr, err = l.ReadSeekCloser()
 		if err != nil {
@@ -312,7 +327,7 @@ func (l *genericResource) Publish() error {
 		defer fr.Close()
 
 		var fw io.WriteCloser
-		fw, err = helpers.OpenFilesForWriting(l.spec.BaseFs.PublishFs, l.getTargetFilenames()...)
+		fw, err = helpers.OpenFilesForWriting(l.spec.BaseFs.PublishFs, targetFilenames...)
 		if err != nil {
 			return
 		}
@@ -475,33 +490,6 @@ func (l genericResource) clone() *genericResource {
 	return &l
 }
 
-// returns an opened file or nil if nothing to write (it may already be published).
-func (l *genericResource) openDestinationsForWriting() (w io.WriteCloser, err error) {
-	l.publishInit.Do(func() {
-		targetFilenames := l.getTargetFilenames()
-		var changedFilenames []string
-
-		// Fast path:
-		// This is a processed version of the original;
-		// check if it already exists at the destination.
-		for _, targetFilename := range targetFilenames {
-			if _, err := l.getSpec().BaseFs.PublishFs.Stat(targetFilename); err == nil {
-				continue
-			}
-
-			changedFilenames = append(changedFilenames, targetFilename)
-		}
-
-		if len(changedFilenames) == 0 {
-			return
-		}
-
-		w, err = helpers.OpenFilesForWriting(l.getSpec().BaseFs.PublishFs, changedFilenames...)
-	})
-
-	return
-}
-
 func (r *genericResource) openPublishFileForWriting(relTargetPath string) (io.WriteCloser, error) {
 	return helpers.OpenFilesForWriting(r.spec.BaseFs.PublishFs, r.relTargetPathsFor(relTargetPath)...)
 }
@@ -622,6 +610,9 @@ type resourceFileInfo struct {
 	// the path to the file on the real filesystem.
 	sourceFilename string
 
+	// For performance. This means that whenever the content changes, the filename changes.
+	sourceFilenameIsHash bool
+
 	fi hugofs.FileMetaInfo
 
 	// A hash of the source content. Is only calculated in caching situations.
@@ -654,6 +645,10 @@ func (fi *resourceFileInfo) setSourceFilename(s string) {
 	fi.sourceFilename = s
 }
 
+func (fi *resourceFileInfo) setSourfeFilenameIsHash(b bool) {
+	fi.sourceFilenameIsHash = b
+}
+
 func (fi *resourceFileInfo) getSourceFs() afero.Fs {
 	return fi.sourceFs
 }