hugolib: Fix bundle resource publishing when multiple output formats

The faulty logic published the bundled resources for the "first output" format.

This worked most of the time, but since the output formats list is sorted,
any output format only used for some of the pages (e.g. CSS) would not work properly.

Fixes #5858

hugolib/page.go

@@ -360,40 +360,44 @@ func (p *pageState) setPages(pages page.Pages) {
 	p.pages = pages
 }
 
-func (p *pageState) renderResources() error {
-	var toBeDeleted []int
+func (p *pageState) renderResources() (err error) {
+	p.resourcesPublishInit.Do(func() {
+		var toBeDeleted []int
 
-	for i, r := range p.Resources() {
-		if _, ok := r.(page.Page); ok {
-			// Pages gets rendered with the owning page but we count them here.
-			p.s.PathSpec.ProcessingStats.Incr(&p.s.PathSpec.ProcessingStats.Pages)
-			continue
-		}
-
-		src, ok := r.(resource.Source)
-		if !ok {
-			return errors.Errorf("Resource %T does not support resource.Source", src)
-		}
-
-		if err := src.Publish(); err != nil {
-			if os.IsNotExist(err) {
-				// The resource has been deleted from the file system.
-				// This should be extremely rare, but can happen on live reload in server
-				// mode when the same resource is member of different page bundles.
-				toBeDeleted = append(toBeDeleted, i)
-			} else {
-				p.s.Log.ERROR.Printf("Failed to publish Resource for page %q: %s", p.pathOrTitle(), err)
+		for i, r := range p.Resources() {
+			if _, ok := r.(page.Page); ok {
+				// Pages gets rendered with the owning page but we count them here.
+				p.s.PathSpec.ProcessingStats.Incr(&p.s.PathSpec.ProcessingStats.Pages)
+				continue
+			}
+
+			src, ok := r.(resource.Source)
+			if !ok {
+				err = errors.Errorf("Resource %T does not support resource.Source", src)
+				return
+			}
+
+			if err := src.Publish(); err != nil {
+				if os.IsNotExist(err) {
+					// The resource has been deleted from the file system.
+					// This should be extremely rare, but can happen on live reload in server
+					// mode when the same resource is member of different page bundles.
+					toBeDeleted = append(toBeDeleted, i)
+				} else {
+					p.s.Log.ERROR.Printf("Failed to publish Resource for page %q: %s", p.pathOrTitle(), err)
+				}
+			} else {
+				p.s.PathSpec.ProcessingStats.Incr(&p.s.PathSpec.ProcessingStats.Files)
 			}
-		} else {
-			p.s.PathSpec.ProcessingStats.Incr(&p.s.PathSpec.ProcessingStats.Files)
 		}
-	}
 
-	for _, i := range toBeDeleted {
-		p.deleteResource(i)
-	}
+		for _, i := range toBeDeleted {
+			p.deleteResource(i)
+		}
 
-	return nil
+	})
+
+	return
 }
 
 func (p *pageState) deleteResource(i int) {

hugolib/page__common.go

@@ -91,8 +91,9 @@ type pageCommon struct {
 	pagesInit sync.Once
 
 	// Any bundled resources
-	resources     resource.Resources
-	resourcesInit sync.Once
+	resources            resource.Resources
+	resourcesInit        sync.Once
+	resourcesPublishInit sync.Once
 
 	translations    page.Pages
 	allTranslations page.Pages

hugolib/pagebundler_test.go

@@ -896,3 +896,37 @@ TheContent.
 
 	return ps, clean, workDir
 }
+
+// https://github.com/gohugoio/hugo/issues/5858
+func TestBundledResourcesWhenMultipleOutputFormats(t *testing.T) {
+	t.Parallel()
+
+	b := newTestSitesBuilder(t).Running().WithConfigFile("toml", `
+baseURL = "https://example.org"
+[outputs]
+  # This looks odd, but it triggers the behaviour in #5858
+  # The total output formats list gets sorted, so CSS before HTML.
+  home = [ "CSS" ]
+
+`)
+	b.WithContent("mybundle/index.md", `
+---
+title: Page
+date: 2017-01-15
+---
+`,
+		"mybundle/data.json", "MyData",
+	)
+
+	b.CreateSites().Build(BuildCfg{})
+
+	b.AssertFileContent("public/mybundle/data.json", "MyData")
+
+	// Change the bundled JSON file and make sure it gets republished.
+	b.EditFiles("content/mybundle/data.json", "My changed data")
+
+	b.Build(BuildCfg{})
+
+	b.AssertFileContent("public/mybundle/data.json", "My changed data")
+
+}

hugolib/shortcode_test.go

@@ -903,6 +903,7 @@ func TestShortcodeParentResourcesOnRebuild(t *testing.T) {
 	b.WithTemplatesAdded(
 		"index.html", `
 {{ $b := .Site.GetPage "b1" }}
+b1 Content: {{ $b.Content }}
 {{$p := $b.Resources.GetMatch "p1*" }}
 Content: {{ $p.Content }}
 {{ $article := .Site.GetPage "blog/article" }}
@@ -933,20 +934,23 @@ SHORTCODE: {{< c >}}
 
 	b.Build(BuildCfg{})
 
-	assert := func() {
-		b.AssertFileContent("public/index.html",
-			"Parent resource: logo.png: /b1/logo.png",
+	assert := func(matchers ...string) {
+		allMatchers := append(matchers, "Parent resource: logo.png: /b1/logo.png",
 			"Article Content: <p>SHORTCODE: \n\n* Parent resource: logo-article.png: /blog/logo-article.png",
 		)
+
+		b.AssertFileContent("public/index.html",
+			allMatchers...,
+		)
 	}
 
 	assert()
 
-	b.EditFiles("b1/index.md", pageContent+" Edit.")
+	b.EditFiles("content/b1/index.md", pageContent+" Edit.")
 
 	b.Build(BuildCfg{})
 
-	assert()
+	assert("Edit.")
 
 }
 

hugolib/site_render.go

@@ -35,6 +35,7 @@ type siteRenderContext struct {
 	sitesOutIdx int
 
 	// Zero based index of the output formats configured within a Site.
+	// Note that these outputs are sorted, so CSS will come before HTML.
 	outIdx int
 
 	multihost bool
@@ -130,11 +131,9 @@ func pageRenderer(
 			continue
 		}
 
-		if ctx.outIdx == 0 {
-			if err := p.renderResources(); err != nil {
-				s.SendError(p.errorf(err, "failed to render page resources"))
-				continue
-			}
+		if err := p.renderResources(); err != nil {
+			s.SendError(p.errorf(err, "failed to render page resources"))
+			continue
 		}
 
 		layouts, err := p.getLayouts()