Refactor markup render system (#32645)

This PR mainly removes some global variables, moves some code and
renames some functions to make code clearer.

This PR also removes a testing-only option ForceHardLineBreak during
refactoring since the behavior is clear now.

7 files changed, 179 insertions, 216 deletions

diff --git a/modules/markup/html.go b/modules/markup/html.go
index 0b1e9b3224..04b768bb8e 100644
--- a/modules/markup/html.go
+++ b/modules/markup/html.go
@@ -5,9 +5,9 @@ package markup
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"regexp"
-	"slices"
 	"strings"
 	"sync"
 
@@ -133,75 +133,49 @@ func CustomLinkURLSchemes(schemes []string) {
 	common.GlobalVars().LinkRegex, _ = xurls.StrictMatchingScheme(strings.Join(withAuth, "|"))
 }
 
-type postProcessError struct {
-	context string
-	err     error
-}
-
-func (p *postProcessError) Error() string {
-	return "PostProcess: " + p.context + ", " + p.err.Error()
-}
-
 type processor func(ctx *RenderContext, node *html.Node)
 
-var defaultProcessors = []processor{
-	fullIssuePatternProcessor,
-	comparePatternProcessor,
-	codePreviewPatternProcessor,
-	fullHashPatternProcessor,
-	shortLinkProcessor,
-	linkProcessor,
-	mentionProcessor,
-	issueIndexPatternProcessor,
-	commitCrossReferencePatternProcessor,
-	hashCurrentPatternProcessor,
-	emailAddressProcessor,
-	emojiProcessor,
-	emojiShortCodeProcessor,
-}
-
-// PostProcess does the final required transformations to the passed raw HTML
+// PostProcessDefault does the final required transformations to the passed raw HTML
 // data, and ensures its validity. Transformations include: replacing links and
 // emails with HTML links, parsing shortlinks in the format of [[Link]], like
 // MediaWiki, linking issues in the format #ID, and mentions in the format
 // @user, and others.
-func PostProcess(ctx *RenderContext, input io.Reader, output io.Writer) error {
-	return postProcess(ctx, defaultProcessors, input, output)
-}
-
-var commitMessageProcessors = []processor{
-	fullIssuePatternProcessor,
-	comparePatternProcessor,
-	fullHashPatternProcessor,
-	linkProcessor,
-	mentionProcessor,
-	issueIndexPatternProcessor,
-	commitCrossReferencePatternProcessor,
-	hashCurrentPatternProcessor,
-	emailAddressProcessor,
-	emojiProcessor,
-	emojiShortCodeProcessor,
+func PostProcessDefault(ctx *RenderContext, input io.Reader, output io.Writer) error {
+	procs := []processor{
+		fullIssuePatternProcessor,
+		comparePatternProcessor,
+		codePreviewPatternProcessor,
+		fullHashPatternProcessor,
+		shortLinkProcessor,
+		linkProcessor,
+		mentionProcessor,
+		issueIndexPatternProcessor,
+		commitCrossReferencePatternProcessor,
+		hashCurrentPatternProcessor,
+		emailAddressProcessor,
+		emojiProcessor,
+		emojiShortCodeProcessor,
+	}
+	return postProcess(ctx, procs, input, output)
 }
 
 // RenderCommitMessage will use the same logic as PostProcess, but will disable
-// the shortLinkProcessor and will add a defaultLinkProcessor if defaultLink is
-// set, which changes every text node into a link to the passed default link.
+// the shortLinkProcessor.
 func RenderCommitMessage(ctx *RenderContext, content string) (string, error) {
-	procs := commitMessageProcessors
-	return renderProcessString(ctx, procs, content)
-}
-
-var commitMessageSubjectProcessors = []processor{
-	fullIssuePatternProcessor,
-	comparePatternProcessor,
-	fullHashPatternProcessor,
-	linkProcessor,
-	mentionProcessor,
-	issueIndexPatternProcessor,
-	commitCrossReferencePatternProcessor,
-	hashCurrentPatternProcessor,
-	emojiShortCodeProcessor,
-	emojiProcessor,
+	procs := []processor{
+		fullIssuePatternProcessor,
+		comparePatternProcessor,
+		fullHashPatternProcessor,
+		linkProcessor,
+		mentionProcessor,
+		issueIndexPatternProcessor,
+		commitCrossReferencePatternProcessor,
+		hashCurrentPatternProcessor,
+		emailAddressProcessor,
+		emojiProcessor,
+		emojiShortCodeProcessor,
+	}
+	return postProcessString(ctx, procs, content)
 }
 
 var emojiProcessors = []processor{
@@ -214,7 +188,18 @@ var emojiProcessors = []processor{
 // emailAddressProcessor, will add a defaultLinkProcessor if defaultLink is set,
 // which changes every text node into a link to the passed default link.
 func RenderCommitMessageSubject(ctx *RenderContext, defaultLink, content string) (string, error) {
-	procs := slices.Clone(commitMessageSubjectProcessors)
+	procs := []processor{
+		fullIssuePatternProcessor,
+		comparePatternProcessor,
+		fullHashPatternProcessor,
+		linkProcessor,
+		mentionProcessor,
+		issueIndexPatternProcessor,
+		commitCrossReferencePatternProcessor,
+		hashCurrentPatternProcessor,
+		emojiShortCodeProcessor,
+		emojiProcessor,
+	}
 	procs = append(procs, func(ctx *RenderContext, node *html.Node) {
 		ch := &html.Node{Parent: node, Type: html.TextNode, Data: node.Data}
 		node.Type = html.ElementNode
@@ -223,19 +208,19 @@ func RenderCommitMessageSubject(ctx *RenderContext, defaultLink, content string)
 		node.Attr = []html.Attribute{{Key: "href", Val: defaultLink}, {Key: "class", Val: "muted"}}
 		node.FirstChild, node.LastChild = ch, ch
 	})
-	return renderProcessString(ctx, procs, content)
+	return postProcessString(ctx, procs, content)
 }
 
 // RenderIssueTitle to process title on individual issue/pull page
 func RenderIssueTitle(ctx *RenderContext, title string) (string, error) {
 	// do not render other issue/commit links in an issue's title - which in most cases is already a link.
-	return renderProcessString(ctx, []processor{
+	return postProcessString(ctx, []processor{
 		emojiShortCodeProcessor,
 		emojiProcessor,
 	}, title)
 }
 
-func renderProcessString(ctx *RenderContext, procs []processor, content string) (string, error) {
+func postProcessString(ctx *RenderContext, procs []processor, content string) (string, error) {
 	var buf strings.Builder
 	if err := postProcess(ctx, procs, strings.NewReader(content), &buf); err != nil {
 		return "", err
@@ -246,7 +231,7 @@ func renderProcessString(ctx *RenderContext, procs []processor, content string)
 // RenderDescriptionHTML will use similar logic as PostProcess, but will
 // use a single special linkProcessor.
 func RenderDescriptionHTML(ctx *RenderContext, content string) (string, error) {
-	return renderProcessString(ctx, []processor{
+	return postProcessString(ctx, []processor{
 		descriptionLinkProcessor,
 		emojiShortCodeProcessor,
 		emojiProcessor,
@@ -256,7 +241,7 @@ func RenderDescriptionHTML(ctx *RenderContext, content string) (string, error) {
 // RenderEmoji for when we want to just process emoji and shortcodes
 // in various places it isn't already run through the normal markdown processor
 func RenderEmoji(ctx *RenderContext, content string) (string, error) {
-	return renderProcessString(ctx, emojiProcessors, content)
+	return postProcessString(ctx, emojiProcessors, content)
 }
 
 func postProcess(ctx *RenderContext, procs []processor, input io.Reader, output io.Writer) error {
@@ -276,7 +261,7 @@ func postProcess(ctx *RenderContext, procs []processor, input io.Reader, output
 		strings.NewReader("</body></html>"),
 	))
 	if err != nil {
-		return &postProcessError{"invalid HTML", err}
+		return fmt.Errorf("markup.postProcess: invalid HTML: %w", err)
 	}
 
 	if node.Type == html.DocumentNode {
@@ -308,7 +293,7 @@ func postProcess(ctx *RenderContext, procs []processor, input io.Reader, output
 	// Render everything to buf.
 	for _, node := range newNodes {
 		if err := html.Render(output, node); err != nil {
-			return &postProcessError{"error rendering processed HTML", err}
+			return fmt.Errorf("markup.postProcess: html.Render: %w", err)
 		}
 	}
 	return nil
diff --git a/modules/markup/html_internal_test.go b/modules/markup/html_internal_test.go
index 7f2057a343..651e674108 100644
--- a/modules/markup/html_internal_test.go
+++ b/modules/markup/html_internal_test.go
@@ -277,12 +277,12 @@ func TestRender_AutoLink(t *testing.T) {
 
 	test := func(input, expected string) {
 		var buffer strings.Builder
-		err := PostProcess(NewTestRenderContext(localMetas), strings.NewReader(input), &buffer)
+		err := PostProcessDefault(NewTestRenderContext(localMetas), strings.NewReader(input), &buffer)
 		assert.Equal(t, err, nil)
 		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(buffer.String()))
 
 		buffer.Reset()
-		err = PostProcess(NewTestRenderContext(localMetas), strings.NewReader(input), &buffer)
+		err = PostProcessDefault(NewTestRenderContext(localMetas), strings.NewReader(input), &buffer)
 		assert.Equal(t, err, nil)
 		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(buffer.String()))
 	}
diff --git a/modules/markup/html_test.go b/modules/markup/html_test.go
index f806f66d11..54bd91f3b3 100644
--- a/modules/markup/html_test.go
+++ b/modules/markup/html_test.go
@@ -445,14 +445,14 @@ func Test_ParseClusterFuzz(t *testing.T) {
 	data := "<A><maTH><tr><MN><bodY ÿ><temPlate></template><tH><tr></A><tH><d<bodY "
 
 	var res strings.Builder
-	err := markup.PostProcess(markup.NewTestRenderContext(localMetas), strings.NewReader(data), &res)
+	err := markup.PostProcessDefault(markup.NewTestRenderContext(localMetas), strings.NewReader(data), &res)
 	assert.NoError(t, err)
 	assert.NotContains(t, res.String(), "<html")
 
 	data = "<!DOCTYPE html>\n<A><maTH><tr><MN><bodY ÿ><temPlate></template><tH><tr></A><tH><d<bodY "
 
 	res.Reset()
-	err = markup.PostProcess(markup.NewTestRenderContext(localMetas), strings.NewReader(data), &res)
+	err = markup.PostProcessDefault(markup.NewTestRenderContext(localMetas), strings.NewReader(data), &res)
 
 	assert.NoError(t, err)
 	assert.NotContains(t, res.String(), "<html")
@@ -464,7 +464,7 @@ func TestPostProcess_RenderDocument(t *testing.T) {
 
 	test := func(input, expected string) {
 		var res strings.Builder
-		err := markup.PostProcess(markup.NewTestRenderContext(markup.TestAppURL, map[string]string{"user": "go-gitea", "repo": "gitea"}), strings.NewReader(input), &res)
+		err := markup.PostProcessDefault(markup.NewTestRenderContext(markup.TestAppURL, map[string]string{"user": "go-gitea", "repo": "gitea"}), strings.NewReader(input), &res)
 		assert.NoError(t, err)
 		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(res.String()))
 	}
@@ -501,7 +501,7 @@ func TestIssue16020(t *testing.T) {
 	data := `<img src="data:image/png;base64,i//V"/>`
 
 	var res strings.Builder
-	err := markup.PostProcess(markup.NewTestRenderContext(localMetas), strings.NewReader(data), &res)
+	err := markup.PostProcessDefault(markup.NewTestRenderContext(localMetas), strings.NewReader(data), &res)
 	assert.NoError(t, err)
 	assert.Equal(t, data, res.String())
 }
@@ -514,7 +514,7 @@ func BenchmarkEmojiPostprocess(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		var res strings.Builder
-		err := markup.PostProcess(markup.NewTestRenderContext(localMetas), strings.NewReader(data), &res)
+		err := markup.PostProcessDefault(markup.NewTestRenderContext(localMetas), strings.NewReader(data), &res)
 		assert.NoError(b, err)
 	}
 }
@@ -522,7 +522,7 @@ func BenchmarkEmojiPostprocess(b *testing.B) {
 func TestFuzz(t *testing.T) {
 	s := "t/l/issues/8#/../../a"
 	renderContext := markup.NewTestRenderContext()
-	err := markup.PostProcess(renderContext, strings.NewReader(s), io.Discard)
+	err := markup.PostProcessDefault(renderContext, strings.NewReader(s), io.Discard)
 	assert.NoError(t, err)
 }
 
@@ -530,7 +530,7 @@ func TestIssue18471(t *testing.T) {
 	data := `http://domain/org/repo/compare/783b039...da951ce`
 
 	var res strings.Builder
-	err := markup.PostProcess(markup.NewTestRenderContext(localMetas), strings.NewReader(data), &res)
+	err := markup.PostProcessDefault(markup.NewTestRenderContext(localMetas), strings.NewReader(data), &res)
 
 	assert.NoError(t, err)
 	assert.Equal(t, `<a href="http://domain/org/repo/compare/783b039...da951ce" class="compare"><code class="nohighlight">783b039...da951ce</code></a>`, res.String())
diff --git a/modules/markup/markdown/goldmark.go b/modules/markup/markdown/goldmark.go
index ed95cecf8b..620a39ebfd 100644
--- a/modules/markup/markdown/goldmark.go
+++ b/modules/markup/markdown/goldmark.go
@@ -80,9 +80,7 @@ func (g *ASTTransformer) Transform(node *ast.Document, reader text.Reader, pc pa
 				// many places render non-comment contents with no mode=document, then these contents also use comment's hard line break setting
 				// especially in many tests.
 				markdownLineBreakStyle := ctx.RenderOptions.Metas["markdownLineBreakStyle"]
-				if markup.RenderBehaviorForTesting.ForceHardLineBreak {
-					v.SetHardLineBreak(true)
-				} else if markdownLineBreakStyle == "comment" {
+				if markdownLineBreakStyle == "comment" {
 					v.SetHardLineBreak(setting.Markdown.EnableHardLineBreakInComments)
 				} else if markdownLineBreakStyle == "document" {
 					v.SetHardLineBreak(setting.Markdown.EnableHardLineBreakInDocuments)
diff --git a/modules/markup/markdown/markdown_test.go b/modules/markup/markdown/markdown_test.go
index aac5ccbb1f..22ab39ebfa 100644
--- a/modules/markup/markdown/markdown_test.go
+++ b/modules/markup/markdown/markdown_test.go
@@ -85,8 +85,89 @@ func TestRender_Images(t *testing.T) {
 		`<p><a href="`+href+`" rel="nofollow"><img src="`+result+`" alt="`+title+`"/></a></p>`)
 }
 
-func testAnswers(baseURL string) []string {
-	return []string{
+func TestTotal_RenderString(t *testing.T) {
+	defer test.MockVariableValue(&markup.RenderBehaviorForTesting.DisableAdditionalAttributes, true)()
+
+	// Test cases without ambiguous links (It is not right to copy a whole file here, instead it should clearly test what is being tested)
+	sameCases := []string{
+		// dear imgui wiki markdown extract: special wiki syntax
+		`Wiki! Enjoy :)
+- [[Links, Language bindings, Engine bindings|Links]]
+- [[Tips]]
+
+See commit 65f1bf27bc
+
+Ideas and codes
+
+- Bezier widget (by @r-lyeh) ` + AppURL + `ocornut/imgui/issues/786
+- Bezier widget (by @r-lyeh) ` + FullURL + `issues/786
+- Node graph editors https://github.com/ocornut/imgui/issues/306
+- [[Memory Editor|memory_editor_example]]
+- [[Plot var helper|plot_var_example]]`,
+		// wine-staging wiki home extract: tables, special wiki syntax, images
+		`## What is Wine Staging?
+**Wine Staging** on website [wine-staging.com](http://wine-staging.com).
+
+## Quick Links
+Here are some links to the most important topics. You can find the full list of pages at the sidebar.
+
+| [[images/icon-install.png]]    | [[Installation]]                                         |
+|--------------------------------|----------------------------------------------------------|
+| [[images/icon-usage.png]]      | [[Usage]]                                                |
+`,
+		// libgdx wiki page: inline images with special syntax
+		`[Excelsior JET](http://www.excelsiorjet.com/) allows you to create native executables for Windows, Linux and Mac OS X.
+
+1. [Package your libGDX application](https://github.com/libgdx/libgdx/wiki/Gradle-on-the-Commandline#packaging-for-the-desktop)
+[[images/1.png]]
+2. Perform a test run by hitting the Run! button.
+[[images/2.png]]
+
+## More tests {#custom-id}
+
+(from https://www.markdownguide.org/extended-syntax/)
+
+### Checkboxes
+
+- [ ] unchecked
+- [x] checked
+- [ ] still unchecked
+
+### Definition list
+
+First Term
+: This is the definition of the first term.
+
+Second Term
+: This is one definition of the second term.
+: This is another definition of the second term.
+
+### Footnotes
+
+Here is a simple footnote,[^1] and here is a longer one.[^bignote]
+
+[^1]: This is the first footnote.
+
+[^bignote]: Here is one with multiple paragraphs and code.
+
+    Indent paragraphs to include them in the footnote.
+
+    ` + "`{ my code }`" + `
+
+    Add as many paragraphs as you like.
+`,
+		`
+- [ ] <!-- rebase-check --> If you want to rebase/retry this PR, click this checkbox.
+
+---
+
+This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
+
+<!-- test-comment -->`,
+	}
+
+	baseURL := ""
+	testAnswers := []string{
 		`<p>Wiki! Enjoy :)</p>
 <ul>
 <li><a href="` + baseURL + `/Links" rel="nofollow">Links, Language bindings, Engine bindings</a></li>
@@ -123,9 +204,9 @@ func testAnswers(baseURL string) []string {
 `,
 		`<p><a href="http://www.excelsiorjet.com/" rel="nofollow">Excelsior JET</a> allows you to create native executables for Windows, Linux and Mac OS X.</p>
 <ol>
-<li><a href="https://github.com/libgdx/libgdx/wiki/Gradle-on-the-Commandline#packaging-for-the-desktop" rel="nofollow">Package your libGDX application</a><br/>
+<li><a href="https://github.com/libgdx/libgdx/wiki/Gradle-on-the-Commandline#packaging-for-the-desktop" rel="nofollow">Package your libGDX application</a>
 <a href="` + baseURL + `/images/1.png" rel="nofollow"><img src="` + baseURL + `/images/1.png" title="1.png" alt="images/1.png"/></a></li>
-<li>Perform a test run by hitting the Run! button.<br/>
+<li>Perform a test run by hitting the Run! button.
 <a href="` + baseURL + `/images/2.png" rel="nofollow"><img src="` + baseURL + `/images/2.png" title="2.png" alt="images/2.png"/></a></li>
 </ol>
 <h2 id="user-content-custom-id">More tests</h2>
@@ -160,106 +241,24 @@ func testAnswers(baseURL string) []string {
 </li>
 </ol>
 </div>
-`, `<ul>
+`,
+		`<ul>
 <li class="task-list-item"><input type="checkbox" disabled="" data-source-position="3"/> If you want to rebase/retry this PR, click this checkbox.</li>
 </ul>
 <hr/>
 <p>This PR has been generated by <a href="https://github.com/renovatebot/renovate" rel="nofollow">Renovate Bot</a>.</p>
 `,
 	}
-}
-
-// Test cases without ambiguous links
-var sameCases = []string{
-	// dear imgui wiki markdown extract: special wiki syntax
-	`Wiki! Enjoy :)
-- [[Links, Language bindings, Engine bindings|Links]]
-- [[Tips]]
 
-See commit 65f1bf27bc
-
-Ideas and codes
-
-- Bezier widget (by @r-lyeh) ` + AppURL + `ocornut/imgui/issues/786
-- Bezier widget (by @r-lyeh) ` + FullURL + `issues/786
-- Node graph editors https://github.com/ocornut/imgui/issues/306
-- [[Memory Editor|memory_editor_example]]
-- [[Plot var helper|plot_var_example]]`,
-	// wine-staging wiki home extract: tables, special wiki syntax, images
-	`## What is Wine Staging?
-**Wine Staging** on website [wine-staging.com](http://wine-staging.com).
-
-## Quick Links
-Here are some links to the most important topics. You can find the full list of pages at the sidebar.
-
-| [[images/icon-install.png]]    | [[Installation]]                                         |
-|--------------------------------|----------------------------------------------------------|
-| [[images/icon-usage.png]]      | [[Usage]]                                                |
-`,
-	// libgdx wiki page: inline images with special syntax
-	`[Excelsior JET](http://www.excelsiorjet.com/) allows you to create native executables for Windows, Linux and Mac OS X.
-
-1. [Package your libGDX application](https://github.com/libgdx/libgdx/wiki/Gradle-on-the-Commandline#packaging-for-the-desktop)
-[[images/1.png]]
-2. Perform a test run by hitting the Run! button.
-[[images/2.png]]
-
-## More tests {#custom-id}
-
-(from https://www.markdownguide.org/extended-syntax/)
-
-### Checkboxes
-
-- [ ] unchecked
-- [x] checked
-- [ ] still unchecked
-
-### Definition list
-
-First Term
-: This is the definition of the first term.
-
-Second Term
-: This is one definition of the second term.
-: This is another definition of the second term.
-
-### Footnotes
-
-Here is a simple footnote,[^1] and here is a longer one.[^bignote]
-
-[^1]: This is the first footnote.
-
-[^bignote]: Here is one with multiple paragraphs and code.
-
-    Indent paragraphs to include them in the footnote.
-
-    ` + "`{ my code }`" + `
-
-    Add as many paragraphs as you like.
-`,
-	`
-- [ ] <!-- rebase-check --> If you want to rebase/retry this PR, click this checkbox.
-
----
-
-This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
-
-<!-- test-comment -->`,
-}
-
-func TestTotal_RenderString(t *testing.T) {
-	defer test.MockVariableValue(&markup.RenderBehaviorForTesting.ForceHardLineBreak, true)()
-	defer test.MockVariableValue(&markup.RenderBehaviorForTesting.DisableAdditionalAttributes, true)()
 	markup.Init(&markup.RenderHelperFuncs{
 		IsUsernameMentionable: func(ctx context.Context, username string) bool {
 			return username == "r-lyeh"
 		},
 	})
-	answers := testAnswers("")
 	for i := 0; i < len(sameCases); i++ {
 		line, err := markdown.RenderString(markup.NewTestRenderContext(localMetas), sameCases[i])
 		assert.NoError(t, err)
-		assert.Equal(t, answers[i], string(line))
+		assert.Equal(t, testAnswers[i], string(line))
 	}
 }
 
@@ -312,10 +311,9 @@ func TestRenderSiblingImages_Issue12925(t *testing.T) {
 	testcase := `![image1](/image1)
 ![image2](/image2)
 `
-	expected := `<p><a href="/image1" target="_blank" rel="nofollow noopener"><img src="/image1" alt="image1"></a><br>
+	expected := `<p><a href="/image1" target="_blank" rel="nofollow noopener"><img src="/image1" alt="image1"></a>
 <a href="/image2" target="_blank" rel="nofollow noopener"><img src="/image2" alt="image2"></a></p>
 `
-	defer test.MockVariableValue(&markup.RenderBehaviorForTesting.ForceHardLineBreak, true)()
 	res, err := markdown.RenderRawString(markup.NewTestRenderContext(), testcase)
 	assert.NoError(t, err)
 	assert.Equal(t, expected, res)
@@ -525,43 +523,33 @@ mail@domain.com
   space${SPACE}${SPACE}
 `
 	input = strings.ReplaceAll(input, "${SPACE}", " ") // replace ${SPACE} with " ", to avoid some editor's auto-trimming
-	cases := []struct {
-		Expected string
-	}{
-		{
-			Expected: `<p>space @mention-user<br/>
-/just/a/path.bin<br/>
-<a href="https://example.com/file.bin" rel="nofollow">https://example.com/file.bin</a><br/>
-<a href="/file.bin" rel="nofollow">local link</a><br/>
-<a href="https://example.com" rel="nofollow">remote link</a><br/>
-<a href="/file.bin" rel="nofollow">local link</a><br/>
-<a href="https://example.com" rel="nofollow">remote link</a><br/>
-<a href="/image.jpg" target="_blank" rel="nofollow noopener"><img src="/image.jpg" alt="local image"/></a><br/>
-<a href="/path/file" target="_blank" rel="nofollow noopener"><img src="/path/file" alt="local image"/></a><br/>
-<a href="/path/file" target="_blank" rel="nofollow noopener"><img src="/path/file" alt="local image"/></a><br/>
-<a href="https://example.com/image.jpg" target="_blank" rel="nofollow noopener"><img src="https://example.com/image.jpg" alt="remote image"/></a><br/>
-<a href="/image.jpg" rel="nofollow"><img src="/image.jpg" title="local image" alt="local image"/></a><br/>
-<a href="https://example.com/image.jpg" rel="nofollow"><img src="https://example.com/image.jpg" title="remote link" alt="remote link"/></a><br/>
-<a href="https://example.com/user/repo/compare/88fc37a3c0a4dda553bdcfc80c178a58247f42fb...12fc37a3c0a4dda553bdcfc80c178a58247f42fb#hash" rel="nofollow"><code>88fc37a3c0...12fc37a3c0 (hash)</code></a><br/>
-com 88fc37a3c0a4dda553bdcfc80c178a58247f42fb...12fc37a3c0a4dda553bdcfc80c178a58247f42fb pare<br/>
-<a href="https://example.com/user/repo/commit/88fc37a3c0a4dda553bdcfc80c178a58247f42fb" rel="nofollow"><code>88fc37a3c0</code></a><br/>
-com 88fc37a3c0a4dda553bdcfc80c178a58247f42fb mit<br/>
-<span class="emoji" aria-label="thumbs up">👍</span><br/>
-<a href="mailto:mail@domain.com" rel="nofollow">mail@domain.com</a><br/>
-@mention-user test<br/>
-#123<br/>
+	expected := `<p>space @mention-user<br/>
+/just/a/path.bin
+<a href="https://example.com/file.bin" rel="nofollow">https://example.com/file.bin</a>
+<a href="/file.bin" rel="nofollow">local link</a>
+<a href="https://example.com" rel="nofollow">remote link</a>
+<a href="/file.bin" rel="nofollow">local link</a>
+<a href="https://example.com" rel="nofollow">remote link</a>
+<a href="/image.jpg" target="_blank" rel="nofollow noopener"><img src="/image.jpg" alt="local image"/></a>
+<a href="/path/file" target="_blank" rel="nofollow noopener"><img src="/path/file" alt="local image"/></a>
+<a href="/path/file" target="_blank" rel="nofollow noopener"><img src="/path/file" alt="local image"/></a>
+<a href="https://example.com/image.jpg" target="_blank" rel="nofollow noopener"><img src="https://example.com/image.jpg" alt="remote image"/></a>
+<a href="/image.jpg" rel="nofollow"><img src="/image.jpg" title="local image" alt="local image"/></a>
+<a href="https://example.com/image.jpg" rel="nofollow"><img src="https://example.com/image.jpg" title="remote link" alt="remote link"/></a>
+<a href="https://example.com/user/repo/compare/88fc37a3c0a4dda553bdcfc80c178a58247f42fb...12fc37a3c0a4dda553bdcfc80c178a58247f42fb#hash" rel="nofollow"><code>88fc37a3c0...12fc37a3c0 (hash)</code></a>
+com 88fc37a3c0a4dda553bdcfc80c178a58247f42fb...12fc37a3c0a4dda553bdcfc80c178a58247f42fb pare
+<a href="https://example.com/user/repo/commit/88fc37a3c0a4dda553bdcfc80c178a58247f42fb" rel="nofollow"><code>88fc37a3c0</code></a>
+com 88fc37a3c0a4dda553bdcfc80c178a58247f42fb mit
+<span class="emoji" aria-label="thumbs up">👍</span>
+<a href="mailto:mail@domain.com" rel="nofollow">mail@domain.com</a>
+@mention-user test
+#123
 space</p>
-`,
-		},
-	}
-
-	defer test.MockVariableValue(&markup.RenderBehaviorForTesting.ForceHardLineBreak, true)()
+`
 	defer test.MockVariableValue(&markup.RenderBehaviorForTesting.DisableAdditionalAttributes, true)()
-	for i, c := range cases {
-		result, err := markdown.RenderString(markup.NewTestRenderContext(localMetas), input)
-		assert.NoError(t, err, "Unexpected error in testcase: %v", i)
-		assert.Equal(t, c.Expected, string(result), "Unexpected result in testcase %v", i)
-	}
+	result, err := markdown.RenderString(markup.NewTestRenderContext(localMetas), input)
+	assert.NoError(t, err)
+	assert.Equal(t, expected, string(result))
 }
 
 func TestAttention(t *testing.T) {
diff --git a/modules/markup/render.go b/modules/markup/render.go
index be75d08c8c..3b112b1a14 100644
--- a/modules/markup/render.go
+++ b/modules/markup/render.go
@@ -28,14 +28,6 @@ const (
 )
 
 var RenderBehaviorForTesting struct {
-	// Markdown line break rendering has 2 default behaviors:
-	// * Use hard: replace "\n" with "<br>" for comments, setting.Markdown.EnableHardLineBreakInComments=true
-	// * Keep soft: "\n" for non-comments (a.k.a. documents), setting.Markdown.EnableHardLineBreakInDocuments=false
-	// In history, there was a mess:
-	// * The behavior was controlled by `Metas["mode"] != "document",
-	// * However, many places render the content without setting "mode" in Metas, all these places used comment line break setting incorrectly
-	ForceHardLineBreak bool
-
 	// Gitea will emit some additional attributes for various purposes, these attributes don't affect rendering.
 	// But there are too many hard-coded test cases, to avoid changing all of them again and again, we can disable emitting these internal attributes.
 	DisableAdditionalAttributes bool
@@ -218,7 +210,7 @@ func render(ctx *RenderContext, renderer Renderer, input io.Reader, output io.Wr
 
 	eg.Go(func() (err error) {
 		if r, ok := renderer.(PostProcessRenderer); ok && r.NeedPostProcess() {
-			err = PostProcess(ctx, pr1, pw2)
+			err = PostProcessDefault(ctx, pr1, pw2)
 		} else {
 			_, err = io.Copy(pw2, pr1)
 		}
diff --git a/tests/fuzz/fuzz_test.go b/tests/fuzz/fuzz_test.go
index 946f7c46f1..01d562d995 100644
--- a/tests/fuzz/fuzz_test.go
+++ b/tests/fuzz/fuzz_test.go
@@ -27,6 +27,6 @@ func FuzzMarkdownRenderRaw(f *testing.F) {
 func FuzzMarkupPostProcess(f *testing.F) {
 	f.Fuzz(func(t *testing.T, data []byte) {
 		setting.AppURL = "http://localhost:3000/"
-		markup.PostProcess(newFuzzRenderContext(), bytes.NewReader(data), io.Discard)
+		markup.PostProcessDefault(newFuzzRenderContext(), bytes.NewReader(data), io.Discard)
 	})
 }