Fix some server rebuild issues for non-HTML custom output formats

The failing test case here is

* A custom search output format defined on the home page, marked as ´noAlternative` and not `permalinkable`
* In fast render mode, when making a change to a data source for that search output format, the JSON file was not refreshed.

There are variants of the above, but the gist of it is:

* The change set was correctly determined, but since the search JSON file was not in the recently visited browser stack, we skipped rendering it.

Running with `hugo server --disableFastRender` would be a workaround for the above.

This commit fixes this by:

* Adding a check for the HTTP request header `Sec-Fetch-Mode = navigation` to the condition for if we should track server request as a user navigation (and not e.g. a HTTP request for a linked CSS stylesheet).
* Making sure that we compare against the real relative URL for non-permalinkable output formats.

Fixes #13014

commands/server.go

@@ -364,7 +364,11 @@ func (f *fileServer) createEndpoint(i int) (*http.ServeMux, net.Listener, string
 			}
 
 			if f.c.fastRenderMode && f.c.errState.buildErr() == nil {
-				if strings.HasSuffix(requestURI, "/") || strings.HasSuffix(requestURI, "html") || strings.HasSuffix(requestURI, "htm") {
+				// Sec-Fetch-Dest = document
+				// Sec-Fetch-Mode should be sent by all recent browser versions, see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Sec-Fetch-Mode#navigate
+				// Fall back to the file extension if not set.
+				// The main take here is that we don't want to have CSS/JS files etc. partake in this logic.
+				if r.Header.Get("Sec-Fetch-Mode") == "navigate" || strings.HasSuffix(requestURI, "/") || strings.HasSuffix(requestURI, "html") || strings.HasSuffix(requestURI, "htm") {
 					if !f.c.visitedURLs.Contains(requestURI) {
 						// If not already on stack, re-render that single page.
 						if err := f.c.partialReRender(requestURI); err != nil {

common/types/evictingqueue.go

@@ -88,6 +88,9 @@ func (q *EvictingStringQueue) Peek() string {
 
 // PeekAll looks at all the elements in the queue, with the newest first.
 func (q *EvictingStringQueue) PeekAll() []string {
+	if q == nil {
+		return nil
+	}
 	q.mu.Lock()
 	vals := make([]string, len(q.vals))
 	copy(vals, q.vals)

hugolib/hugo_sites.go

@@ -430,6 +430,7 @@ type BuildCfg struct {
 
 // shouldRender returns whether this output format should be rendered or not.
 func (cfg *BuildCfg) shouldRender(p *pageState) bool {
+	// TODO1
 	if p.skipRender() {
 		return false
 	}
@@ -457,18 +458,18 @@ func (cfg *BuildCfg) shouldRender(p *pageState) bool {
 		return false
 	}
 
-	if p.outputFormat().IsHTML {
-		// This is fast render mode and the output format is HTML,
-		// rerender if this page is one of the recently visited.
-		return cfg.RecentlyVisited.Contains(p.RelPermalink())
+	if relURL := p.getRelURL(); relURL != "" {
+		if cfg.RecentlyVisited.Contains(relURL) {
+			return true
+		}
 	}
 
 	// In fast render mode, we want to avoid re-rendering the sitemaps etc. and
 	// other big listings whenever we e.g. change a content file,
 	// but we want partial renders of the recently visited pages to also include
 	// alternative formats of the same HTML page (e.g. RSS, JSON).
 	for _, po := range p.pageOutputs {
-		if po.render && po.f.IsHTML && cfg.RecentlyVisited.Contains(po.RelPermalink()) {
+		if po.render && po.f.IsHTML && cfg.RecentlyVisited.Contains(po.getRelURL()) {
 			return true
 		}
 	}

hugolib/hugo_sites_build.go

@@ -46,7 +46,6 @@ import (
 	"github.com/gohugoio/hugo/common/paths"
 	"github.com/gohugoio/hugo/common/rungroup"
 	"github.com/gohugoio/hugo/config"
-	"github.com/gohugoio/hugo/resources/page"
 	"github.com/gohugoio/hugo/resources/page/siteidentities"
 	"github.com/gohugoio/hugo/resources/postpub"
 
@@ -902,16 +901,6 @@ func (h *HugoSites) processPartialFileEvents(ctx context.Context, l logg.LevelLo
 
 			needsPagesAssemble = true
 
-			if config.RecentlyVisited != nil {
-				// Fast render mode. Adding them to the visited queue
-				// avoids rerendering them on navigation.
-				for _, id := range changes {
-					if p, ok := id.(page.Page); ok {
-						config.RecentlyVisited.Add(p.RelPermalink())
-					}
-				}
-			}
-
 			h.pageTrees.treeTaxonomyEntries.DeletePrefix("")
 
 			if delete && !isContentDataFile {

hugolib/page__paths.go

@@ -71,11 +71,17 @@ func newPagePaths(ps *pageState) (pagePaths, error) {
 		// Use the main format for permalinks, usually HTML.
 		permalinksIndex := 0
 		if f.Permalinkable {
-			// Unless it's permalinkable
+			// Unless it's permalinkable.
 			permalinksIndex = i
 		}
 
+		relURL := relPermalink
+		if relURL == "" {
+			relURL = paths.RelPermalink(s.PathSpec)
+		}
+
 		targets[f.Name] = targetPathsHolder{
+			relURL:       relURL,
 			paths:        paths,
 			OutputFormat: pageOutputFormats[permalinksIndex],
 		}

hugolib/page__per_output.go

@@ -469,13 +469,21 @@ type pagePerOutputProviders interface {
 
 type targetPather interface {
 	targetPaths() page.TargetPaths
+	getRelURL() string
 }
 
 type targetPathsHolder struct {
-	paths page.TargetPaths
+	// relURL is usually the same as OutputFormat.RelPermalink, but can be different
+	// for non-permalinkable output formats. These shares RelPermalink with the main (first) output format.
+	relURL string
+	paths  page.TargetPaths
 	page.OutputFormat
 }
 
+func (t targetPathsHolder) getRelURL() string {
+	return t.relURL
+}
+
 func (t targetPathsHolder) targetPaths() page.TargetPaths {
 	return t.paths
 }

hugolib/rebuild_test.go

@@ -1181,6 +1181,49 @@ Content: {{ .Content }}
 	b.AssertFileContent("public/index.html", "Content: <p>Home</p>")
 }
 
+// Issue #13014.
+func TestRebuildEditNotPermalinkableCustomOutputFormatTemplateInFastRenderMode(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+baseURL = "https://example.com/docs/"
+disableLiveReload = true
+[internal]
+fastRenderMode = true
+disableKinds = ["taxonomy", "term", "sitemap", "robotsTXT", "404"]
+[outputFormats]
+  [outputFormats.SearchIndex]
+    baseName = 'Search'
+    isPlainText = true
+    mediaType = 'text/plain'
+    noAlternative = true
+	permalinkable = false
+
+[outputs]
+  home = ['HTML', 'SearchIndex']
+-- content/_index.md --
+---
+title: "Home"
+---
+Home.
+-- layouts/index.html --
+Home.
+-- layouts/_default/index.searchindex.txt --
+Text. {{ .Title }}|{{ .RelPermalink }}|
+
+`
+	b := TestRunning(t, files, TestOptInfo())
+
+	b.AssertFileContent("public/search.txt", "Text.")
+
+	b.EditFileReplaceAll("layouts/_default/index.searchindex.txt", "Text.", "Text Edited.").Build()
+
+	b.BuildPartial("/docs/search.txt")
+
+	b.AssertFileContent("public/search.txt", "Text Edited.")
+}
+
 func TestRebuildVariationsAssetsJSImport(t *testing.T) {
 	t.Parallel()
 	files := `