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

5 files changed, 81 insertions, 39 deletions

diff --git a/hugolib/page.go b/hugolib/page.go
index ec4b23d90..537482fb2 100644
--- a/hugolib/page.go
+++ b/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
-
-	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
-		}
+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)
-		}
+			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)
+			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.Log.ERROR.Printf("Failed to publish Resource for page %q: %s", p.pathOrTitle(), err)
+				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) {
diff --git a/hugolib/page__common.go b/hugolib/page__common.go
index 5bd7223cc..01280bb40 100644
--- a/hugolib/page__common.go
+++ b/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
diff --git a/hugolib/pagebundler_test.go b/hugolib/pagebundler_test.go
index 870ea3de9..06bd64154 100644
--- a/hugolib/pagebundler_test.go
+++ b/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")
+
+}
diff --git a/hugolib/shortcode_test.go b/hugolib/shortcode_test.go
index 3320e642c..dd01eb5c5 100644
--- a/hugolib/shortcode_test.go
+++ b/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.")
 
 }
 
diff --git a/hugolib/site_render.go b/hugolib/site_render.go
index 407061b67..9ade951df 100644
--- a/hugolib/site_render.go
+++ b/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()