Refactor render system (#32492)

There were too many patches to the Render system, it's really difficult
to make further improvements.

This PR clears the legacy problems and fix TODOs.

1. Rename `RenderContext.Type` to `RenderContext.MarkupType` to clarify
its usage.
2. Use `ContentMode` to replace `meta["mode"]` and `IsWiki`, to clarify
the rendering behaviors.
3. Use "wiki" mode instead of "mode=gfm + wiki=true"
4. Merge `renderByType` and `renderByFile`
5. Add more comments

----

The problem of "mode=document": in many cases it is not set, so many
non-comment places use comment's hard line break incorrectly

8 files changed, 50 insertions, 69 deletions

diff --git a/routers/api/v1/misc/markup.go b/routers/api/v1/misc/markup.go
index 9699c79368..868ed92519 100644
--- a/routers/api/v1/misc/markup.go
+++ b/routers/api/v1/misc/markup.go
@@ -9,6 +9,7 @@ import (
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/markup/markdown"
 	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/routers/common"
 	"code.gitea.io/gitea/services/context"
@@ -41,7 +42,8 @@ func Markup(ctx *context.APIContext) {
 		return
 	}
 
-	common.RenderMarkup(ctx.Base, ctx.Repo, form.Mode, form.Text, form.Context, form.FilePath, form.Wiki)
+	mode := util.Iif(form.Wiki, "wiki", form.Mode) //nolint:staticcheck
+	common.RenderMarkup(ctx.Base, ctx.Repo, mode, form.Text, form.Context, form.FilePath)
 }
 
 // Markdown render markdown document to HTML
@@ -71,12 +73,8 @@ func Markdown(ctx *context.APIContext) {
 		return
 	}
 
-	mode := "markdown"
-	if form.Mode == "comment" || form.Mode == "gfm" {
-		mode = form.Mode
-	}
-
-	common.RenderMarkup(ctx.Base, ctx.Repo, mode, form.Text, form.Context, "", form.Wiki)
+	mode := util.Iif(form.Wiki, "wiki", form.Mode) //nolint:staticcheck
+	common.RenderMarkup(ctx.Base, ctx.Repo, mode, form.Text, form.Context, "")
 }
 
 // MarkdownRaw render raw markdown HTML
diff --git a/routers/api/v1/misc/markup_test.go b/routers/api/v1/misc/markup_test.go
index abffdf3516..6b8c09034a 100644
--- a/routers/api/v1/misc/markup_test.go
+++ b/routers/api/v1/misc/markup_test.go
@@ -14,6 +14,7 @@ import (
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/setting"
 	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/modules/test"
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/services/contexttest"
 
@@ -24,6 +25,7 @@ const AppURL = "http://localhost:3000/"
 
 func testRenderMarkup(t *testing.T, mode string, wiki bool, filePath, text, expectedBody string, expectedCode int) {
 	setting.AppURL = AppURL
+	defer test.MockVariableValue(&markup.RenderBehaviorForTesting.DisableInternalAttributes, true)()
 	context := "/gogits/gogs"
 	if !wiki {
 		context += path.Join("/src/branch/main", path.Dir(filePath))
@@ -38,13 +40,13 @@ func testRenderMarkup(t *testing.T, mode string, wiki bool, filePath, text, expe
 	ctx, resp := contexttest.MockAPIContext(t, "POST /api/v1/markup")
 	web.SetForm(ctx, &options)
 	Markup(ctx)
-	actual := strings.ReplaceAll(resp.Body.String(), ` data-markdown-generated-content=""`, "")
-	assert.Equal(t, expectedBody, actual)
+	assert.Equal(t, expectedBody, resp.Body.String())
 	assert.Equal(t, expectedCode, resp.Code)
 	resp.Body.Reset()
 }
 
 func testRenderMarkdown(t *testing.T, mode string, wiki bool, text, responseBody string, responseCode int) {
+	defer test.MockVariableValue(&markup.RenderBehaviorForTesting.DisableInternalAttributes, true)()
 	setting.AppURL = AppURL
 	context := "/gogits/gogs"
 	if !wiki {
@@ -59,8 +61,7 @@ func testRenderMarkdown(t *testing.T, mode string, wiki bool, text, responseBody
 	ctx, resp := contexttest.MockAPIContext(t, "POST /api/v1/markdown")
 	web.SetForm(ctx, &options)
 	Markdown(ctx)
-	actual := strings.ReplaceAll(resp.Body.String(), ` data-markdown-generated-content=""`, "")
-	assert.Equal(t, responseBody, actual)
+	assert.Equal(t, responseBody, resp.Body.String())
 	assert.Equal(t, responseCode, resp.Code)
 	resp.Body.Reset()
 }
@@ -158,8 +159,8 @@ Here are some links to the most important topics. You can find the full list of
 <a href="http://localhost:3000/gogits/gogs/media/branch/main/path/image.png" target="_blank" rel="nofollow noopener"><img src="http://localhost:3000/gogits/gogs/media/branch/main/path/image.png" alt="Image"/></a></p>
 `, http.StatusOK)
 
-	testRenderMarkup(t, "file", true, "path/test.unknown", "## Test", "Unsupported render extension: .unknown\n", http.StatusUnprocessableEntity)
-	testRenderMarkup(t, "unknown", true, "", "## Test", "Unknown mode: unknown\n", http.StatusUnprocessableEntity)
+	testRenderMarkup(t, "file", false, "path/test.unknown", "## Test", "unsupported file to render: \"path/test.unknown\"\n", http.StatusUnprocessableEntity)
+	testRenderMarkup(t, "unknown", false, "", "## Test", "Unknown mode: unknown\n", http.StatusUnprocessableEntity)
 }
 
 var simpleCases = []string{
diff --git a/routers/common/markup.go b/routers/common/markup.go
index 0a00eac7d4..c8cc1a5ff1 100644
--- a/routers/common/markup.go
+++ b/routers/common/markup.go
@@ -5,21 +5,22 @@
 package common
 
 import (
+	"errors"
 	"fmt"
 	"net/http"
 	"path"
 	"strings"
 
-	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/modules/httplib"
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/markup/markdown"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/services/context"
 )
 
 // RenderMarkup renders markup text for the /markup and /markdown endpoints
-func RenderMarkup(ctx *context.Base, repo *context.Repository, mode, text, urlPathContext, filePath string, wiki bool) {
+func RenderMarkup(ctx *context.Base, repo *context.Repository, mode, text, urlPathContext, filePath string) {
 	// urlPathContext format is "/subpath/{user}/{repo}/src/{branch, commit, tag}/{identifier/path}/{file/dir}"
 	// filePath is the path of the file to render if the end user is trying to preview a repo file (mode == "file")
 	// filePath will be used as RenderContext.RelativePath
@@ -27,32 +28,33 @@ func RenderMarkup(ctx *context.Base, repo *context.Repository, mode, text, urlPa
 	// for example, when previewing file "/gitea/owner/repo/src/branch/features/feat-123/doc/CHANGE.md", then filePath is "doc/CHANGE.md"
 	// and the urlPathContext is "/gitea/owner/repo/src/branch/features/feat-123/doc"
 
-	var markupType, relativePath string
-
-	links := markup.Links{AbsolutePrefix: true}
+	renderCtx := &markup.RenderContext{
+		Ctx:        ctx,
+		Links:      markup.Links{AbsolutePrefix: true},
+		MarkupType: markdown.MarkupName,
+	}
 	if urlPathContext != "" {
-		links.Base = fmt.Sprintf("%s%s", httplib.GuessCurrentHostURL(ctx), urlPathContext)
+		renderCtx.Links.Base = fmt.Sprintf("%s%s", httplib.GuessCurrentHostURL(ctx), urlPathContext)
 	}
 
-	switch mode {
-	case "markdown":
-		// Raw markdown
-		if err := markdown.RenderRaw(&markup.RenderContext{
-			Ctx:   ctx,
-			Links: links,
-		}, strings.NewReader(text), ctx.Resp); err != nil {
+	if mode == "" || mode == "markdown" {
+		// raw markdown doesn't need any special handling
+		if err := markdown.RenderRaw(renderCtx, strings.NewReader(text), ctx.Resp); err != nil {
 			ctx.Error(http.StatusInternalServerError, err.Error())
 		}
 		return
+	}
+	switch mode {
+	case "gfm": // legacy mode, do nothing
 	case "comment":
-		// Issue & comment content
-		markupType = markdown.MarkupName
-	case "gfm":
-		// GitHub Flavored Markdown
-		markupType = markdown.MarkupName
+		renderCtx.ContentMode = markup.RenderContentAsComment
+	case "wiki":
+		renderCtx.ContentMode = markup.RenderContentAsWiki
 	case "file":
-		markupType = "" // render the repo file content by its extension
-		relativePath = filePath
+		// render the repo file content by its extension
+		renderCtx.MarkupType = ""
+		renderCtx.RelativePath = filePath
+		renderCtx.InStandalonePage = true
 	default:
 		ctx.Error(http.StatusUnprocessableEntity, fmt.Sprintf("Unknown mode: %s", mode))
 		return
@@ -67,33 +69,19 @@ func RenderMarkup(ctx *context.Base, repo *context.Repository, mode, text, urlPa
 		refPath := strings.Join(fields[3:], "/")           // it is "branch/features/feat-12/doc"
 		refPath = strings.TrimSuffix(refPath, "/"+fileDir) // now we get the correct branch path: "branch/features/feat-12"
 
-		links = markup.Links{AbsolutePrefix: true, Base: absoluteBasePrefix, BranchPath: refPath, TreePath: fileDir}
+		renderCtx.Links = markup.Links{AbsolutePrefix: true, Base: absoluteBasePrefix, BranchPath: refPath, TreePath: fileDir}
 	}
 
-	meta := map[string]string{}
-	var repoCtx *repo_model.Repository
 	if repo != nil && repo.Repository != nil {
-		repoCtx = repo.Repository
-		if mode == "comment" {
-			meta = repo.Repository.ComposeMetas(ctx)
+		renderCtx.Repo = repo.Repository
+		if renderCtx.ContentMode == markup.RenderContentAsComment {
+			renderCtx.Metas = repo.Repository.ComposeMetas(ctx)
 		} else {
-			meta = repo.Repository.ComposeDocumentMetas(ctx)
+			renderCtx.Metas = repo.Repository.ComposeDocumentMetas(ctx)
 		}
 	}
-	if mode != "comment" {
-		meta["mode"] = "document"
-	}
-
-	if err := markup.Render(&markup.RenderContext{
-		Ctx:          ctx,
-		Repo:         repoCtx,
-		Links:        links,
-		Metas:        meta,
-		IsWiki:       wiki,
-		Type:         markupType,
-		RelativePath: relativePath,
-	}, strings.NewReader(text), ctx.Resp); err != nil {
-		if markup.IsErrUnsupportedRenderExtension(err) {
+	if err := markup.Render(renderCtx, strings.NewReader(text), ctx.Resp); err != nil {
+		if errors.Is(err, util.ErrInvalidArgument) {
 			ctx.Error(http.StatusUnprocessableEntity, err.Error())
 		} else {
 			ctx.Error(http.StatusInternalServerError, err.Error())
diff --git a/routers/web/feed/convert.go b/routers/web/feed/convert.go
index 3f33e9933a..a273515c8a 100644
--- a/routers/web/feed/convert.go
+++ b/routers/web/feed/convert.go
@@ -56,7 +56,6 @@ func renderMarkdown(ctx *context.Context, act *activities_model.Action, content
 		Links: markup.Links{
 			Base: act.GetRepoLink(ctx),
 		},
-		Type: markdown.MarkupName,
 		Metas: map[string]string{
 			"user": act.GetRepoUserName(ctx),
 			"repo": act.GetRepoName(ctx),
diff --git a/routers/web/misc/markup.go b/routers/web/misc/markup.go
index 2dbbd6fc09..0c7ec6c2eb 100644
--- a/routers/web/misc/markup.go
+++ b/routers/web/misc/markup.go
@@ -6,6 +6,7 @@ package misc
 
 import (
 	api "code.gitea.io/gitea/modules/structs"
+	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/routers/common"
 	"code.gitea.io/gitea/services/context"
@@ -14,5 +15,6 @@ import (
 // Markup render markup document to HTML
 func Markup(ctx *context.Context) {
 	form := web.GetForm(ctx).(*api.MarkupOption)
-	common.RenderMarkup(ctx.Base, ctx.Repo, form.Mode, form.Text, form.Context, form.FilePath, form.Wiki)
+	mode := util.Iif(form.Wiki, "wiki", form.Mode) //nolint:staticcheck
+	common.RenderMarkup(ctx.Base, ctx.Repo, mode, form.Text, form.Context, form.FilePath)
 }
diff --git a/routers/web/repo/view.go b/routers/web/repo/view.go
index 7d9281b397..7030f6d8a9 100644
--- a/routers/web/repo/view.go
+++ b/routers/web/repo/view.go
@@ -312,6 +312,7 @@ func renderReadmeFile(ctx *context.Context, subfolder string, readmeFile *git.Tr
 
 		ctx.Data["EscapeStatus"], ctx.Data["FileContent"], err = markupRender(ctx, &markup.RenderContext{
 			Ctx:          ctx,
+			MarkupType:   markupType,
 			RelativePath: path.Join(ctx.Repo.TreePath, readmeFile.Name()), // ctx.Repo.TreePath is the directory not the Readme so we must append the Readme filename (and path).
 			Links: markup.Links{
 				Base:       ctx.Repo.RepoLink,
@@ -502,28 +503,20 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry) {
 		ctx.Data["ReadmeExist"] = readmeExist
 
 		markupType := markup.DetectMarkupTypeByFileName(blob.Name())
-		// If the markup is detected by custom markup renderer it should not be reset later on
-		// to not pass it down to the render context.
-		detected := false
 		if markupType == "" {
-			detected = true
 			markupType = markup.DetectRendererType(blob.Name(), bytes.NewReader(buf))
 		}
 		if markupType != "" {
 			ctx.Data["HasSourceRenderedToggle"] = true
 		}
-
 		if markupType != "" && !shouldRenderSource {
 			ctx.Data["IsMarkup"] = true
 			ctx.Data["MarkupType"] = markupType
-			if !detected {
-				markupType = ""
-			}
 			metas := ctx.Repo.Repository.ComposeDocumentMetas(ctx)
 			metas["BranchNameSubURL"] = ctx.Repo.BranchNameSubURL()
 			ctx.Data["EscapeStatus"], ctx.Data["FileContent"], err = markupRender(ctx, &markup.RenderContext{
 				Ctx:          ctx,
-				Type:         markupType,
+				MarkupType:   markupType,
 				RelativePath: ctx.Repo.TreePath,
 				Links: markup.Links{
 					Base:       ctx.Repo.RepoLink,
@@ -615,6 +608,7 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry) {
 			ctx.Data["MarkupType"] = markupType
 			ctx.Data["EscapeStatus"], ctx.Data["FileContent"], err = markupRender(ctx, &markup.RenderContext{
 				Ctx:          ctx,
+				MarkupType:   markupType,
 				RelativePath: ctx.Repo.TreePath,
 				Links: markup.Links{
 					Base:       ctx.Repo.RepoLink,
diff --git a/routers/web/repo/wiki.go b/routers/web/repo/wiki.go
index d2056353d8..2b8312f10a 100644
--- a/routers/web/repo/wiki.go
+++ b/routers/web/repo/wiki.go
@@ -289,12 +289,12 @@ func renderViewPage(ctx *context.Context) (*git.Repository, *git.TreeEntry) {
 	}
 
 	rctx := &markup.RenderContext{
-		Ctx:   ctx,
-		Metas: ctx.Repo.Repository.ComposeDocumentMetas(ctx),
+		Ctx:         ctx,
+		ContentMode: markup.RenderContentAsWiki,
+		Metas:       ctx.Repo.Repository.ComposeDocumentMetas(ctx),
 		Links: markup.Links{
 			Base: ctx.Repo.RepoLink,
 		},
-		IsWiki: true,
 	}
 	buf := &strings.Builder{}
 
diff --git a/routers/web/user/profile.go b/routers/web/user/profile.go
index d0abf603c3..4fbfc2bd17 100644
--- a/routers/web/user/profile.go
+++ b/routers/web/user/profile.go
@@ -258,7 +258,6 @@ func prepareUserProfileTabData(ctx *context.Context, showPrivate bool, profileDb
 					Base:       profileDbRepo.Link(),
 					BranchPath: path.Join("branch", util.PathEscapeSegments(profileDbRepo.DefaultBranch)),
 				},
-				Metas: map[string]string{"mode": "document"},
 			}, bytes); err != nil {
 				log.Error("failed to RenderString: %v", err)
 			} else {