Implement cascading front matter

Fixes gohugoio#6041

hugolib/page.go

@@ -520,7 +520,7 @@ func (p *pageState) addResources(r ...resource.Resource) {
 	p.resources = append(p.resources, r...)
 }
 
-func (p *pageState) mapContent(meta *pageMeta) error {
+func (p *pageState) mapContent(bucket *pagesMapBucket, meta *pageMeta) error {
 
 	s := p.shortcodeState
 
@@ -563,7 +563,7 @@ Loop:
 				}
 			}
 
-			if err := meta.setMetadata(p, m); err != nil {
+			if err := meta.setMetadata(bucket, p, m); err != nil {
 				return err
 			}
 

hugolib/page__common.go

@@ -35,6 +35,9 @@ type pageCommon struct {
 	// Laziliy initialized dependencies.
 	init *lazy.Init
 
+	metaInit   sync.Once
+	metaInitFn func(bucket *pagesMapBucket) error
+
 	// All of these represents the common parts of a page.Page
 	maps.Scratcher
 	navigation.PageMenusProvider

hugolib/page__meta.go

@@ -306,7 +306,7 @@ func (p *pageMeta) Weight() int {
 	return p.weight
 }
 
-func (pm *pageMeta) setMetadata(p *pageState, frontmatter map[string]interface{}) error {
+func (pm *pageMeta) setMetadata(bucket *pagesMapBucket, p *pageState, frontmatter map[string]interface{}) error {
 	if frontmatter == nil {
 		return errors.New("missing frontmatter data")
 	}
@@ -316,6 +316,15 @@ func (pm *pageMeta) setMetadata(p *pageState, frontmatter map[string]interface{}
 	// Needed for case insensitive fetching of params values
 	maps.ToLower(frontmatter)
 
+	if bucket.cascade != nil {
+		// TODO(bep) cascade tolower
+		for k, v := range bucket.cascade {
+			if _, found := frontmatter[k]; !found {
+				frontmatter[k] = v
+			}
+		}
+	}
+
 	var mtime time.Time
 	if p.File().FileInfo() != nil {
 		mtime = p.File().FileInfo().ModTime()
@@ -370,6 +379,12 @@ func (pm *pageMeta) setMetadata(p *pageState, frontmatter map[string]interface{}
 		case "linktitle":
 			pm.linkTitle = cast.ToString(v)
 			pm.params[loki] = pm.linkTitle
+		case "cascade":
+			if p.IsNode() {
+				bucket.cascade = cast.ToStringMap(v)
+			} else {
+				pm.params[loki] = v
+			}
 		case "summary":
 			pm.summary = cast.ToString(v)
 			pm.params[loki] = pm.summary

hugolib/page__new.go

@@ -211,12 +211,16 @@ func newPageWithContent(f *fileInfo, s *Site, bundled bool, content resource.Ope
 
 	ps.shortcodeState = newShortcodeHandler(ps, ps.s, nil)
 
-	if err := ps.mapContent(metaProvider); err != nil {
-		return nil, ps.wrapError(err)
-	}
+	ps.metaInitFn = func(bucket *pagesMapBucket) error {
+		if err := ps.mapContent(bucket, metaProvider); err != nil {
+			return ps.wrapError(err)
+		}
 
-	if err := metaProvider.applyDefaultValues(); err != nil {
-		return nil, err
+		if err := metaProvider.applyDefaultValues(); err != nil {
+			return err
+		}
+
+		return nil
 	}
 
 	ps.init.Add(func() (interface{}, error) {

hugolib/pagecollections.go

@@ -387,6 +387,7 @@ func (c *PageCollections) clearResourceCacheForPage(page *pageState) {
 }
 
 func (c *PageCollections) assemblePagesMap(s *Site) error {
+
 	c.pagesMap = newPagesMap(s)
 
 	rootSections := make(map[string]bool)
@@ -449,13 +450,19 @@ func (c *PageCollections) createWorkAllPages() error {
 				panic(fmt.Sprintf("[BUG] parent bucket not found for %q", s))
 			}
 			parentBucket = parentv.(*pagesMapBucket)
+			if bucket.cascade == nil {
+				// Fetch it from above
+				bucket.cascade = parentBucket.cascade
+			}
 
 			if !mainSectionsFound && strings.Count(s, "/") == 1 {
 				// Root section
 				rootBuckets = append(rootBuckets, bucket)
 			}
 		}
 
+		c.pagesMap.initPageMeta(bucket.owner, bucket)
+
 		if bucket.owner.IsHome() {
 			if resource.IsZeroDates(bucket.owner) {
 				// Calculate dates from the page tree.
@@ -477,6 +484,7 @@ func (c *PageCollections) createWorkAllPages() error {
 
 		tmp := bucket.pages[:0]
 		for _, x := range bucket.pages {
+			c.pagesMap.initPageMeta(x.(*pageState), bucket)
 			if c.pagesMap.s.shouldBuild(x) {
 				tmp = append(tmp, x)
 			}

hugolib/pages_map.go

@@ -126,6 +126,15 @@ func (m *pagesMap) addPage(p *pageState) {
 	bucket.pages = append(bucket.pages, p)
 }
 
+func (m *pagesMap) initPageMeta(p *pageState, bucket *pagesMapBucket) {
+	p.metaInit.Do(func() {
+		if p.metaInitFn != nil {
+			// TODO(bep) cascade error etc.
+			p.metaInitFn(bucket)
+		}
+	})
+}
+
 func (m *pagesMap) withEveryPage(f func(p *pageState)) {
 	m.r.Walk(func(k string, v interface{}) bool {
 		b := v.(*pagesMapBucket)
@@ -312,6 +321,9 @@ type pagesMapBucket struct {
 	// Some additional metatadata attached to this node.
 	meta map[string]interface{}
 
+	// Cascading front matter.
+	cascade map[string]interface{}
+
 	owner *pageState // The branch node
 
 	// When disableKinds is enabled for this node.

hugolib/pages_metadata_handler_test.go

@@ -0,0 +1,103 @@
+// Copyright 2019 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hugolib
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+
+	"github.com/gohugoio/hugo/parser"
+	"github.com/gohugoio/hugo/parser/metadecoders"
+)
+
+func TestCascade(t *testing.T) {
+
+	weight := 0
+
+	p := func(m map[string]interface{}) string {
+		var yamlStr string
+
+		if len(m) > 0 {
+			var b bytes.Buffer
+
+			parser.InterfaceToConfig(m, metadecoders.YAML, &b)
+			yamlStr = b.String()
+		}
+
+		weight += 10
+
+		metaStr := "---\n" + yamlStr + fmt.Sprintf("\nweight: %d\n---", weight)
+
+		return metaStr
+
+	}
+
+	b := newTestSitesBuilder(t).WithConfigFile("toml", `
+baseURL = "https://example.org"
+disableKinds = ["taxonomy", "taxonomyTerm"]
+`)
+	b.WithContent(
+		"_index.md", p(map[string]interface{}{
+			"title": "Home",
+			"cascade": map[string]interface{}{
+				"title": "Cascade Home",
+				"icon":  "home.png",
+			},
+		}),
+		"p1.md", p(map[string]interface{}{
+			"title": "p1",
+		}),
+		"p2.md", p(map[string]interface{}{}),
+		"sect1/_index.md", p(map[string]interface{}{
+			"title": "Sect1",
+			"cascade": map[string]interface{}{
+				"title": "Cascade Sect1",
+				"icon":  "sect1.png",
+			},
+		}),
+		"sect1/s1_2/_index.md", p(map[string]interface{}{
+			"title": "Sect1_2",
+		}),
+		"sect1/s1_2/p1.md", p(map[string]interface{}{
+			"title": "Sect1_2_p1",
+		}),
+		"sect2/_index.md", p(map[string]interface{}{
+			"title": "Sect2",
+		}),
+		"sect2/p1.md", p(map[string]interface{}{
+			"title": "Sect2_p1",
+		}),
+		"sect2/p2.md", p(map[string]interface{}{}),
+	)
+
+	b.WithTemplates("index.html", `
+	
+{{ range .Site.Pages }}
+{{- .Weight }}|{{ .Kind }}|{{ .Path }}|{{ .Title }}|{{ .Params.icon }}|
+{{ end }}
+`)
+
+	b.Build(BuildCfg{})
+
+	b.AssertFileContent("public/index.html", `10|home|_index.md|Home||
+20|page|p1.md|p1|home.png|
+30|page|p2.md|Cascade Home|home.png|
+40|section|sect1/_index.md|Sect1|home.png|
+50|section|sect1/s1_2/_index.md|Sect1_2|sect1.png|
+60|page|sect1/s1_2/p1.md|Sect1_2_p1|sect1.png|
+70|section|sect2/_index.md|Sect2|home.png|
+80|page|sect2/p1.md|Sect2_p1|home.png|
+90|page|sect2/p2.md|Cascade Home|home.png|`)
+}

hugolib/testhelpers_test.go

@@ -649,9 +649,13 @@ func (s *sitesBuilder) AssertHome(matches ...string) {
 func (s *sitesBuilder) AssertFileContent(filename string, matches ...string) {
 	s.T.Helper()
 	content := s.FileContent(filename)
-	for _, match := range matches {
-		if !strings.Contains(content, match) {
-			s.Fatalf("No match for %q in content for %s\n%s\n%q", match, filename, content, content)
+	for _, m := range matches {
+		lines := strings.Split(m, "\n")
+		for _, match := range lines {
+			match = strings.TrimSpace(match)
+			if !strings.Contains(content, match) {
+				s.Fatalf("No match for %q in content for %s\n%s\n%q", match, filename, content, content)
+			}
 		}
 	}
 }