Allow different HardBreaks settings for documents and comments (#11515)

GH has different HardBreaks behaviour for markdown comments and documents.

Comments have hard breaks and documents have soft breaks - therefore Gitea's rendering will always be different from GH's if we only provide one setting.

Here we split the setting in to two - one for documents and one for comments and other things.

Signed-off-by: Andrew Thornton art27@cantab.net

Changes to index.js as per @silverwind 
Co-authored-by: silverwind <me@silverwind.io>

Changes to docs as per @guillep2k 
Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>

12 files changed, 77 insertions, 29 deletions

diff --git a/custom/conf/app.ini.sample b/custom/conf/app.ini.sample
index c8797ca56a..c50dd68f1f 100644
--- a/custom/conf/app.ini.sample
+++ b/custom/conf/app.ini.sample
@@ -216,7 +216,10 @@ EVENT_SOURCE_UPDATE_TIME = 10s
 ; Render soft line breaks as hard line breaks, which means a single newline character between
 ; paragraphs will cause a line break and adding trailing whitespace to paragraphs is not
 ; necessary to force a line break.
-ENABLE_HARD_LINE_BREAK = true
+; Render soft line breaks as hard line breaks for comments
+ENABLE_HARD_LINE_BREAK_IN_COMMENTS = true
+; Render soft line breaks as hard line breaks for markdown documents
+ENABLE_HARD_LINE_BREAK_IN_DOCUMENTS = false
 ; Comma separated list of custom URL-Schemes that are allowed as links when rendering Markdown
 ; for example git,magnet,ftp (more at https://en.wikipedia.org/wiki/List_of_URI_schemes)
 ; URLs starting with http and https are always displayed, whatever is put in this entry.
diff --git a/docs/content/doc/advanced/config-cheat-sheet.en-us.md b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
index 3ad24776ff..e3ff2deb37 100644
--- a/docs/content/doc/advanced/config-cheat-sheet.en-us.md
+++ b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
@@ -152,7 +152,10 @@ Values containing `#` or `;` must be quoted using `` ` `` or `"""`.
 
 ## Markdown (`markdown`)
 
-- `ENABLE_HARD_LINE_BREAK`: **true**: Render soft line breaks as hard line breaks, which
+- `ENABLE_HARD_LINE_BREAK_IN_COMMENTS`: **true**: Render soft line breaks as hard line breaks in comments, which
+  means a single newline character between paragraphs will cause a line break and adding
+  trailing whitespace to paragraphs is not necessary to force a line break.
+- `ENABLE_HARD_LINE_BREAK_IN_DOCUMENTS`: **false**: Render soft line breaks as hard line breaks in documents, which
   means a single newline character between paragraphs will cause a line break and adding
   trailing whitespace to paragraphs is not necessary to force a line break.
 - `CUSTOM_URL_SCHEMES`: Use a comma separated list (ftp,git,svn) to indicate additional
diff --git a/models/repo.go b/models/repo.go
index c45abdf63d..abf32360a4 100644
--- a/models/repo.go
+++ b/models/repo.go
@@ -174,9 +174,10 @@ type Repository struct {
 	*Mirror    `xorm:"-"`
 	Status     RepositoryStatus `xorm:"NOT NULL DEFAULT 0"`
 
-	RenderingMetas  map[string]string `xorm:"-"`
-	Units           []*RepoUnit       `xorm:"-"`
-	PrimaryLanguage *LanguageStat     `xorm:"-"`
+	RenderingMetas         map[string]string `xorm:"-"`
+	DocumentRenderingMetas map[string]string `xorm:"-"`
+	Units                  []*RepoUnit       `xorm:"-"`
+	PrimaryLanguage        *LanguageStat     `xorm:"-"`
 
 	IsFork                          bool               `xorm:"INDEX NOT NULL DEFAULT false"`
 	ForkID                          int64              `xorm:"INDEX"`
@@ -545,11 +546,12 @@ func (repo *Repository) mustOwner(e Engine) *User {
 
 // ComposeMetas composes a map of metas for properly rendering issue links and external issue trackers.
 func (repo *Repository) ComposeMetas() map[string]string {
-	if repo.RenderingMetas == nil {
+	if len(repo.RenderingMetas) == 0 {
 		metas := map[string]string{
 			"user":     repo.OwnerName,
 			"repo":     repo.Name,
 			"repoPath": repo.RepoPath(),
+			"mode":     "comment",
 		}
 
 		unit, err := repo.GetUnit(UnitTypeExternalTracker)
@@ -581,6 +583,19 @@ func (repo *Repository) ComposeMetas() map[string]string {
 	return repo.RenderingMetas
 }
 
+// ComposeDocumentMetas composes a map of metas for properly rendering documents
+func (repo *Repository) ComposeDocumentMetas() map[string]string {
+	if len(repo.DocumentRenderingMetas) == 0 {
+		metas := map[string]string{}
+		for k, v := range repo.ComposeMetas() {
+			metas[k] = v
+		}
+		metas["mode"] = "document"
+		repo.DocumentRenderingMetas = metas
+	}
+	return repo.DocumentRenderingMetas
+}
+
 // DeleteWiki removes the actual and local copy of repository wiki.
 func (repo *Repository) DeleteWiki() error {
 	return repo.deleteWiki(x)
diff --git a/modules/markup/markdown/goldmark.go b/modules/markup/markdown/goldmark.go
index bf02a22d5e..9447424644 100644
--- a/modules/markup/markdown/goldmark.go
+++ b/modules/markup/markdown/goldmark.go
@@ -151,6 +151,16 @@ func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc pa
 					v.AppendChild(v, newChild)
 				}
 			}
+		case *ast.Text:
+			if v.SoftLineBreak() && !v.HardLineBreak() {
+				renderMetas := pc.Get(renderMetasKey).(map[string]string)
+				mode := renderMetas["mode"]
+				if mode != "document" {
+					v.SetHardLineBreak(setting.Markdown.EnableHardLineBreakInComments)
+				} else {
+					v.SetHardLineBreak(setting.Markdown.EnableHardLineBreakInDocuments)
+				}
+			}
 		}
 		return ast.WalkContinue, nil
 	})
diff --git a/modules/markup/markdown/markdown.go b/modules/markup/markdown/markdown.go
index e50301ffe4..515d684686 100644
--- a/modules/markup/markdown/markdown.go
+++ b/modules/markup/markdown/markdown.go
@@ -29,17 +29,19 @@ var once = sync.Once{}
 
 var urlPrefixKey = parser.NewContextKey()
 var isWikiKey = parser.NewContextKey()
+var renderMetasKey = parser.NewContextKey()
 
 // NewGiteaParseContext creates a parser.Context with the gitea context set
-func NewGiteaParseContext(urlPrefix string, isWiki bool) parser.Context {
+func NewGiteaParseContext(urlPrefix string, metas map[string]string, isWiki bool) parser.Context {
 	pc := parser.NewContext(parser.WithIDs(newPrefixedIDs()))
 	pc.Set(urlPrefixKey, urlPrefix)
 	pc.Set(isWikiKey, isWiki)
+	pc.Set(renderMetasKey, metas)
 	return pc
 }
 
-// RenderRaw renders Markdown to HTML without handling special links.
-func RenderRaw(body []byte, urlPrefix string, wikiMarkdown bool) []byte {
+// render renders Markdown to HTML without handling special links.
+func render(body []byte, urlPrefix string, metas map[string]string, wikiMarkdown bool) []byte {
 	once.Do(func() {
 		converter = goldmark.New(
 			goldmark.WithExtensions(extension.Table,
@@ -75,12 +77,9 @@ func RenderRaw(body []byte, urlPrefix string, wikiMarkdown bool) []byte {
 			),
 		)
 
-		if setting.Markdown.EnableHardLineBreak {
-			converter.Renderer().AddOptions(html.WithHardWraps())
-		}
 	})
 
-	pc := NewGiteaParseContext(urlPrefix, wikiMarkdown)
+	pc := NewGiteaParseContext(urlPrefix, metas, wikiMarkdown)
 	var buf bytes.Buffer
 	if err := converter.Convert(giteautil.NormalizeEOL(body), &buf, parser.WithContext(pc)); err != nil {
 		log.Error("Unable to render: %v", err)
@@ -112,7 +111,7 @@ func (Parser) Extensions() []string {
 
 // Render implements markup.Parser
 func (Parser) Render(rawBytes []byte, urlPrefix string, metas map[string]string, isWiki bool) []byte {
-	return RenderRaw(rawBytes, urlPrefix, isWiki)
+	return render(rawBytes, urlPrefix, metas, isWiki)
 }
 
 // Render renders Markdown to HTML with all specific handling stuff.
@@ -120,6 +119,11 @@ func Render(rawBytes []byte, urlPrefix string, metas map[string]string) []byte {
 	return markup.Render("a.md", rawBytes, urlPrefix, metas)
 }
 
+// RenderRaw renders Markdown to HTML without handling special links.
+func RenderRaw(body []byte, urlPrefix string, wikiMarkdown bool) []byte {
+	return render(body, urlPrefix, map[string]string{}, wikiMarkdown)
+}
+
 // RenderString renders Markdown to HTML with special links and returns string type.
 func RenderString(raw, urlPrefix string, metas map[string]string) string {
 	return markup.RenderString("a.md", raw, urlPrefix, metas)
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index 9507d46930..b8ec957535 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -256,12 +256,14 @@ var (
 
 	// Markdown settings
 	Markdown = struct {
-		EnableHardLineBreak bool
-		CustomURLSchemes    []string `ini:"CUSTOM_URL_SCHEMES"`
-		FileExtensions      []string
+		EnableHardLineBreakInComments  bool
+		EnableHardLineBreakInDocuments bool
+		CustomURLSchemes               []string `ini:"CUSTOM_URL_SCHEMES"`
+		FileExtensions                 []string
 	}{
-		EnableHardLineBreak: true,
-		FileExtensions:      strings.Split(".md,.markdown,.mdown,.mkd", ","),
+		EnableHardLineBreakInComments:  true,
+		EnableHardLineBreakInDocuments: false,
+		FileExtensions:                 strings.Split(".md,.markdown,.mdown,.mkd", ","),
 	}
 
 	// Admin settings
diff --git a/routers/api/v1/misc/markdown.go b/routers/api/v1/misc/markdown.go
index 5a44db5e8b..a10c288df4 100644
--- a/routers/api/v1/misc/markdown.go
+++ b/routers/api/v1/misc/markdown.go
@@ -48,10 +48,12 @@ func Markdown(ctx *context.APIContext, form api.MarkdownOption) {
 	}
 
 	switch form.Mode {
+	case "comment":
+		fallthrough
 	case "gfm":
 		md := []byte(form.Text)
 		urlPrefix := form.Context
-		var meta map[string]string
+		meta := map[string]string{}
 		if !strings.HasPrefix(setting.AppSubURL+"/", urlPrefix) {
 			// check if urlPrefix is already set to a URL
 			linkRegex, _ := xurls.StrictMatchingScheme("https?://")
@@ -61,7 +63,15 @@ func Markdown(ctx *context.APIContext, form api.MarkdownOption) {
 			}
 		}
 		if ctx.Repo != nil && ctx.Repo.Repository != nil {
-			meta = ctx.Repo.Repository.ComposeMetas()
+			// "gfm" = Github Flavored Markdown - set this to render as a document
+			if form.Mode == "gfm" {
+				meta = ctx.Repo.Repository.ComposeDocumentMetas()
+			} else {
+				meta = ctx.Repo.Repository.ComposeMetas()
+			}
+		}
+		if form.Mode == "gfm" {
+			meta["mode"] = "document"
 		}
 		if form.Wiki {
 			_, err := ctx.Write([]byte(markdown.RenderWiki(md, urlPrefix, meta)))
diff --git a/routers/api/v1/misc/markdown_test.go b/routers/api/v1/misc/markdown_test.go
index 264a6010f9..6c81ec8eb4 100644
--- a/routers/api/v1/misc/markdown_test.go
+++ b/routers/api/v1/misc/markdown_test.go
@@ -94,7 +94,7 @@ Here are some links to the most important topics. You can find the full list of
 <p><strong>Wine Staging</strong> on website <a href="http://wine-staging.com" rel="nofollow">wine-staging.com</a>.</p>
 <h2 id="user-content-quick-links">Quick Links</h2>
 <p>Here are some links to the most important topics. You can find the full list of pages at the sidebar.</p>
-<p><a href="` + AppSubURL + `wiki/Configuration" rel="nofollow">Configuration</a><br/>
+<p><a href="` + AppSubURL + `wiki/Configuration" rel="nofollow">Configuration</a>
 <a href="` + AppSubURL + `wiki/raw/images/icon-bug.png" rel="nofollow"><img src="` + AppSubURL + `wiki/raw/images/icon-bug.png" title="icon-bug.png" alt="images/icon-bug.png"/></a></p>
 `,
 		// Guard wiki sidebar: special syntax
diff --git a/routers/repo/view.go b/routers/repo/view.go
index 9c9cdc06bf..0f4e2d838c 100644
--- a/routers/repo/view.go
+++ b/routers/repo/view.go
@@ -319,7 +319,7 @@ func renderDirectory(ctx *context.Context, treeLink string) {
 				if markupType := markup.Type(readmeFile.name); markupType != "" {
 					ctx.Data["IsMarkup"] = true
 					ctx.Data["MarkupType"] = string(markupType)
-					ctx.Data["FileContent"] = string(markup.Render(readmeFile.name, buf, readmeTreelink, ctx.Repo.Repository.ComposeMetas()))
+					ctx.Data["FileContent"] = string(markup.Render(readmeFile.name, buf, readmeTreelink, ctx.Repo.Repository.ComposeDocumentMetas()))
 				} else {
 					ctx.Data["IsRenderedHTML"] = true
 					ctx.Data["FileContent"] = strings.Replace(
@@ -459,7 +459,7 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 		if markupType := markup.Type(blob.Name()); markupType != "" {
 			ctx.Data["IsMarkup"] = true
 			ctx.Data["MarkupType"] = markupType
-			ctx.Data["FileContent"] = string(markup.Render(blob.Name(), buf, path.Dir(treeLink), ctx.Repo.Repository.ComposeMetas()))
+			ctx.Data["FileContent"] = string(markup.Render(blob.Name(), buf, path.Dir(treeLink), ctx.Repo.Repository.ComposeDocumentMetas()))
 		} else if readmeExist {
 			ctx.Data["IsRenderedHTML"] = true
 			ctx.Data["FileContent"] = strings.Replace(
@@ -538,7 +538,7 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 			buf = append(buf, d...)
 			ctx.Data["IsMarkup"] = true
 			ctx.Data["MarkupType"] = markupType
-			ctx.Data["FileContent"] = string(markup.Render(blob.Name(), buf, path.Dir(treeLink), ctx.Repo.Repository.ComposeMetas()))
+			ctx.Data["FileContent"] = string(markup.Render(blob.Name(), buf, path.Dir(treeLink), ctx.Repo.Repository.ComposeDocumentMetas()))
 		}
 
 	}
diff --git a/routers/repo/wiki.go b/routers/repo/wiki.go
index cc60b4388d..ac650d3fc4 100644
--- a/routers/repo/wiki.go
+++ b/routers/repo/wiki.go
@@ -209,7 +209,7 @@ func renderViewPage(ctx *context.Context) (*git.Repository, *git.TreeEntry) {
 		return nil, nil
 	}
 
-	metas := ctx.Repo.Repository.ComposeMetas()
+	metas := ctx.Repo.Repository.ComposeDocumentMetas()
 	ctx.Data["content"] = markdown.RenderWiki(data, ctx.Repo.RepoLink, metas)
 	ctx.Data["sidebarPresent"] = sidebarContent != nil
 	ctx.Data["sidebarContent"] = markdown.RenderWiki(sidebarContent, ctx.Repo.RepoLink, metas)
diff --git a/templates/repo/editor/edit.tmpl b/templates/repo/editor/edit.tmpl
index 283bd32508..cc98539eab 100644
--- a/templates/repo/editor/edit.tmpl
+++ b/templates/repo/editor/edit.tmpl
@@ -30,7 +30,7 @@
 				<div class="ui top attached tabular menu" data-write="write" data-preview="preview" data-diff="diff">
 					<a class="active item" data-tab="write">{{svg "octicon-code" 16}} {{if .IsNewFile}}{{.i18n.Tr "repo.editor.new_file"}}{{else}}{{.i18n.Tr "repo.editor.edit_file"}}{{end}}</a>
 					{{if not .IsNewFile}}
-					<a class="item" data-tab="preview" data-url="{{.Repository.APIURL}}/markdown" data-context="{{.RepoLink}}/src/{{.BranchNameSubURL | EscapePound}}" data-preview-file-modes="{{.PreviewableFileModes}}">{{svg "octicon-eye" 16}} {{.i18n.Tr "preview"}}</a>
+					<a class="item" data-tab="preview" data-url="{{.Repository.APIURL}}/markdown" data-context="{{.RepoLink}}/src/{{.BranchNameSubURL | EscapePound}}" data-preview-file-modes="{{.PreviewableFileModes}}" data-markdown-mode="gfm">{{svg "octicon-eye" 16}} {{.i18n.Tr "preview"}}</a>
 					<a class="item" data-tab="diff" data-url="{{.RepoLink}}/_preview/{{.BranchName | EscapePound}}/{{.TreePath | EscapePound}}" data-context="{{.BranchLink}}">{{svg "octicon-diff" 16}} {{.i18n.Tr "repo.editor.preview_changes"}}</a>
 					{{end}}
 				</div>
diff --git a/web_src/js/index.js b/web_src/js/index.js
index 5c749ce4ca..46b0425014 100644
--- a/web_src/js/index.js
+++ b/web_src/js/index.js
@@ -41,7 +41,7 @@ function initCommentPreviewTab($form) {
     const $this = $(this);
     $.post($this.data('url'), {
       _csrf: csrf,
-      mode: 'gfm',
+      mode: 'comment',
       context: $this.data('context'),
       text: $form.find(`.tab[data-tab="${$tabMenu.data('write')}"] textarea`).val()
     }, (data) => {
@@ -65,6 +65,7 @@ function initEditPreviewTab($form) {
     $previewTab.on('click', function () {
       const $this = $(this);
       let context = `${$this.data('context')}/`;
+      const mode = $this.data('markdown-mode') || 'comment';
       const treePathEl = $form.find('input#tree_path');
       if (treePathEl.length > 0) {
         context += treePathEl.val();
@@ -72,7 +73,7 @@ function initEditPreviewTab($form) {
       context = context.substring(0, context.lastIndexOf('/'));
       $.post($this.data('url'), {
         _csrf: csrf,
-        mode: 'gfm',
+        mode,
         context,
         text: $form.find(`.tab[data-tab="${$tabMenu.data('write')}"] textarea`).val()
       }, (data) => {