Fix output format handling for render hooks

Fixes #8176

3 files changed, 54 insertions, 14 deletions

diff --git a/markup/converter/converter.go b/markup/converter/converter.go
index d7e3d4639..3fa3bea39 100644
--- a/markup/converter/converter.go
+++ b/markup/converter/converter.go
@@ -127,7 +127,7 @@ type DocumentContext struct {
 type RenderContext struct {
 	Src         []byte
 	RenderTOC   bool
-	RenderHooks *hooks.Renderers
+	RenderHooks hooks.Renderers
 }
 
 var FeatureRenderHooks = identity.NewPathIdentity("markup", "renderingHooks")
diff --git a/markup/converter/hooks/hooks.go b/markup/converter/hooks/hooks.go
index 6f08a2161..d36dad288 100644
--- a/markup/converter/hooks/hooks.go
+++ b/markup/converter/hooks/hooks.go
@@ -14,7 +14,9 @@
 package hooks
 
 import (
+	"fmt"
 	"io"
+	"strings"
 
 	"github.com/gohugoio/hugo/identity"
 )
@@ -67,26 +69,64 @@ type Renderers struct {
 	HeadingRenderer HeadingRenderer
 }
 
-func (r *Renderers) Eq(other interface{}) bool {
-	ro, ok := other.(*Renderers)
+func (r Renderers) Eq(other interface{}) bool {
+	ro, ok := other.(Renderers)
 	if !ok {
 		return false
 	}
-	if r == nil || ro == nil {
-		return r == nil
+
+	if r.IsZero() || ro.IsZero() {
+		return r.IsZero() && ro.IsZero()
 	}
 
-	if r.ImageRenderer.GetIdentity() != ro.ImageRenderer.GetIdentity() {
+	var b1, b2 bool
+	b1, b2 = r.ImageRenderer == nil, ro.ImageRenderer == nil
+	if (b1 || b2) && (b1 != b2) {
+		return false
+	}
+	if !b1 && r.ImageRenderer.GetIdentity() != ro.ImageRenderer.GetIdentity() {
 		return false
 	}
 
-	if r.LinkRenderer.GetIdentity() != ro.LinkRenderer.GetIdentity() {
+	b1, b2 = r.LinkRenderer == nil, ro.LinkRenderer == nil
+	if (b1 || b2) && (b1 != b2) {
+		return false
+	}
+	if !b1 && r.LinkRenderer.GetIdentity() != ro.LinkRenderer.GetIdentity() {
 		return false
 	}
 
-	if r.HeadingRenderer.GetIdentity() != ro.HeadingRenderer.GetIdentity() {
+	b1, b2 = r.HeadingRenderer == nil, ro.HeadingRenderer == nil
+	if (b1 || b2) && (b1 != b2) {
+		return false
+	}
+	if !b1 && r.HeadingRenderer.GetIdentity() != ro.HeadingRenderer.GetIdentity() {
 		return false
 	}
 
 	return true
 }
+
+func (r Renderers) IsZero() bool {
+	return r.HeadingRenderer == nil && r.LinkRenderer == nil && r.ImageRenderer == nil
+}
+
+func (r Renderers) String() string {
+	if r.IsZero() {
+		return "<zero>"
+	}
+
+	var sb strings.Builder
+
+	if r.LinkRenderer != nil {
+		sb.WriteString(fmt.Sprintf("LinkRenderer<%s>|", r.LinkRenderer.GetIdentity()))
+	}
+	if r.HeadingRenderer != nil {
+		sb.WriteString(fmt.Sprintf("HeadingRenderer<%s>|", r.HeadingRenderer.GetIdentity()))
+	}
+	if r.ImageRenderer != nil {
+		sb.WriteString(fmt.Sprintf("ImageRenderer<%s>|", r.ImageRenderer.GetIdentity()))
+	}
+
+	return sb.String()
+}
diff --git a/markup/goldmark/render_hooks.go b/markup/goldmark/render_hooks.go
index 41db4011b..5e0865a70 100644
--- a/markup/goldmark/render_hooks.go
+++ b/markup/goldmark/render_hooks.go
@@ -206,12 +206,12 @@ func (r *hookedRenderer) renderDefaultImage(w util.BufWriter, source []byte, nod
 
 func (r *hookedRenderer) renderImage(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
 	n := node.(*ast.Image)
-	var h *hooks.Renderers
+	var h hooks.Renderers
 
 	ctx, ok := w.(*renderContext)
 	if ok {
 		h = ctx.RenderContext().RenderHooks
-		ok = h != nil && h.ImageRenderer != nil
+		ok = h.ImageRenderer != nil
 	}
 
 	if !ok {
@@ -267,12 +267,12 @@ func (r *hookedRenderer) renderDefaultLink(w util.BufWriter, source []byte, node
 
 func (r *hookedRenderer) renderLink(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
 	n := node.(*ast.Link)
-	var h *hooks.Renderers
+	var h hooks.Renderers
 
 	ctx, ok := w.(*renderContext)
 	if ok {
 		h = ctx.RenderContext().RenderHooks
-		ok = h != nil && h.LinkRenderer != nil
+		ok = h.LinkRenderer != nil
 	}
 
 	if !ok {
@@ -326,12 +326,12 @@ func (r *hookedRenderer) renderDefaultHeading(w util.BufWriter, source []byte, n
 
 func (r *hookedRenderer) renderHeading(w util.BufWriter, source []byte, node ast.Node, entering bool) (ast.WalkStatus, error) {
 	n := node.(*ast.Heading)
-	var h *hooks.Renderers
+	var h hooks.Renderers
 
 	ctx, ok := w.(*renderContext)
 	if ok {
 		h = ctx.RenderContext().RenderHooks
-		ok = h != nil && h.HeadingRenderer != nil
+		ok = h.HeadingRenderer != nil
 	}
 
 	if !ok {