From 2874fc75ce45b17fd4457440e55660d7118fbc46 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Erik=20Pedersen?=
 <bjorn.erik.pedersen@gmail.com>
Date: Sat, 8 Apr 2017 11:15:28 +0200
Subject: [PATCH] hugolib, output: Add NotAlternative to OutputFormat

To make sure CSS and similar does not appear in the AlternativeOutputFormats list.
---
 hugolib/page_output.go |  6 +++---
 hugolib/site_render.go |  2 +-
 output/outputFormat.go | 17 ++++++++++++-----
 3 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/hugolib/page_output.go b/hugolib/page_output.go
index c6a72d324..7b299b575 100644
--- a/hugolib/page_output.go
+++ b/hugolib/page_output.go
@@ -177,8 +177,6 @@ type OutputFormat struct {
 	// This is value is fetched from the output format definition.
 	// Note that for pages with only one output format,
 	// this method will always return "canonical".
-	// TODO(bep) output -- the above may not be correct for CSS etc. Figure out a way around that.
-	// TODO(bep) output -- re the above, maybe add a "alternate" filter to AlternativeOutputFormats.
 	// As an example, the AMP output format will, by default, return "amphtml".
 	//
 	// See:
@@ -222,10 +220,12 @@ func newOutputFormat(p *Page, f output.Format) *OutputFormat {
 }
 
 // OutputFormats gives the alternative output formats for this PageOutput.
+// Note that we use the term "alternative" and not "alternate" here, as it
+// does not necessarily replace the other format, it is an alternative representation.
 func (p *PageOutput) AlternativeOutputFormats() (OutputFormats, error) {
 	var o OutputFormats
 	for _, of := range p.OutputFormats() {
-		if of.f == p.outputFormat {
+		if of.f.NotAlternative || of.f == p.outputFormat {
 			continue
 		}
 		o = append(o, of)
diff --git a/hugolib/site_render.go b/hugolib/site_render.go
index 0c9da2134..17a14bd10 100644
--- a/hugolib/site_render.go
+++ b/hugolib/site_render.go
@@ -290,7 +290,7 @@ func (s *Site) renderSitemap() error {
 	n.Data["Pages"] = pages
 	n.Pages = pages
 
-	// TODO(bep) output
+	// TODO(bep) we have several of these
 	if err := page.initTargetPathDescriptor(); err != nil {
 		return err
 	}
diff --git a/output/outputFormat.go b/output/outputFormat.go
index bd0236278..0845b5d31 100644
--- a/output/outputFormat.go
+++ b/output/outputFormat.go
@@ -63,6 +63,12 @@ type Format struct {
 
 	// Enable to ignore the global uglyURLs setting.
 	NoUgly bool
+
+	// Enable if it doesn't make sense to include this format in an alternative
+	// format listing, CSS being one good example.
+	// Note that we use the term "alternative" and not "alternate" here, as it
+	// does not necessarily replace the other format, it is an alternative representation.
+	NotAlternative bool
 }
 
 var (
@@ -88,11 +94,12 @@ var (
 	}
 
 	CSSFormat = Format{
-		Name:        "CSS",
-		MediaType:   media.CSSType,
-		BaseName:    "styles",
-		IsPlainText: true,
-		Rel:         "stylesheet",
+		Name:           "CSS",
+		MediaType:      media.CSSType,
+		BaseName:       "styles",
+		IsPlainText:    true,
+		Rel:            "stylesheet",
+		NotAlternative: true,
 	}
 	CSVFormat = Format{
 		Name:        "CSV",