Refactor markup render system (#32612)

This PR removes (almost) all path tricks, and introduces "renderhelper"
package.

Now we can clearly see the rendering behaviors for comment/file/wiki,
more details are in "renderhelper" tests.

Fix #31411 , fix #18592, fix #25632 and maybe more problems. (ps: fix
#32608 by the way)

models/activities/action.go

@@ -200,7 +200,7 @@ func (a *Action) LoadActUser(ctx context.Context) {
 	}
 }
 
-func (a *Action) loadRepo(ctx context.Context) {
+func (a *Action) LoadRepo(ctx context.Context) {
 	if a.Repo != nil {
 		return
 	}
@@ -250,7 +250,7 @@ func (a *Action) GetActDisplayNameTitle(ctx context.Context) string {
 
 // GetRepoUserName returns the name of the action repository owner.
 func (a *Action) GetRepoUserName(ctx context.Context) string {
-	a.loadRepo(ctx)
+	a.LoadRepo(ctx)
 	if a.Repo == nil {
 		return "(non-existing-repo)"
 	}
@@ -265,7 +265,7 @@ func (a *Action) ShortRepoUserName(ctx context.Context) string {
 
 // GetRepoName returns the name of the action repository.
 func (a *Action) GetRepoName(ctx context.Context) string {
-	a.loadRepo(ctx)
+	a.LoadRepo(ctx)
 	if a.Repo == nil {
 		return "(non-existing-repo)"
 	}
@@ -644,7 +644,7 @@ func NotifyWatchers(ctx context.Context, actions ...*Action) error {
 		}
 
 		if repoChanged {
-			act.loadRepo(ctx)
+			act.LoadRepo(ctx)
 			repo = act.Repo
 
 			// check repo owner exist.

models/issues/comment_code.go

@@ -7,8 +7,8 @@ import (
 	"context"
 
 	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/renderhelper"
 	user_model "code.gitea.io/gitea/models/user"
-	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/markup/markdown"
 
 	"xorm.io/builder"
@@ -112,12 +112,8 @@ func findCodeComments(ctx context.Context, opts FindCommentsOptions, issue *Issu
 		}
 
 		var err error
-		rctx := markup.NewRenderContext(ctx).
-			WithRepoFacade(issue.Repo).
-			WithLinks(markup.Links{Base: issue.Repo.Link()}).
-			WithMetas(issue.Repo.ComposeMetas(ctx))
-		if comment.RenderedContent, err = markdown.RenderString(rctx,
-			comment.Content); err != nil {
+		rctx := renderhelper.NewRenderContextRepoComment(ctx, issue.Repo)
+		if comment.RenderedContent, err = markdown.RenderString(rctx, comment.Content); err != nil {
 			return nil, err
 		}
 	}

models/renderhelper/commit_checker.go

@@ -0,0 +1,53 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package renderhelper
+
+import (
+	"context"
+	"io"
+
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/gitrepo"
+	"code.gitea.io/gitea/modules/log"
+)
+
+type commitChecker struct {
+	ctx           context.Context
+	commitCache   map[string]bool
+	gitRepoFacade gitrepo.Repository
+
+	gitRepo       *git.Repository
+	gitRepoCloser io.Closer
+}
+
+func newCommitChecker(ctx context.Context, gitRepo gitrepo.Repository) *commitChecker {
+	return &commitChecker{ctx: ctx, commitCache: make(map[string]bool), gitRepoFacade: gitRepo}
+}
+
+func (c *commitChecker) Close() error {
+	if c != nil && c.gitRepoCloser != nil {
+		return c.gitRepoCloser.Close()
+	}
+	return nil
+}
+
+func (c *commitChecker) IsCommitIDExisting(commitID string) bool {
+	exist, inCache := c.commitCache[commitID]
+	if inCache {
+		return exist
+	}
+
+	if c.gitRepo == nil {
+		r, closer, err := gitrepo.RepositoryFromContextOrOpen(c.ctx, c.gitRepoFacade)
+		if err != nil {
+			log.Error("unable to open repository: %s Error: %v", gitrepo.RepoGitURL(c.gitRepoFacade), err)
+			return false
+		}
+		c.gitRepo, c.gitRepoCloser = r, closer
+	}
+
+	exist = c.gitRepo.IsReferenceExist(commitID) // Don't use IsObjectExist since it doesn't support short hashs with gogit edition.
+	c.commitCache[commitID] = exist
+	return exist
+}

models/renderhelper/main_test.go

@@ -0,0 +1,27 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package renderhelper
+
+import (
+	"context"
+	"testing"
+
+	"code.gitea.io/gitea/models/unittest"
+	"code.gitea.io/gitea/modules/markup"
+)
+
+func TestMain(m *testing.M) {
+	unittest.MainTest(m, &unittest.TestOptions{
+		FixtureFiles: []string{"repository.yml", "user.yml"},
+		SetUp: func() error {
+			markup.RenderBehaviorForTesting.DisableAdditionalAttributes = true
+			markup.Init(&markup.RenderHelperFuncs{
+				IsUsernameMentionable: func(ctx context.Context, username string) bool {
+					return username == "user2"
+				},
+			})
+			return nil
+		},
+	})
+}

models/renderhelper/repo_comment.go

@@ -0,0 +1,73 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package renderhelper
+
+import (
+	"context"
+	"fmt"
+
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/util"
+)
+
+type RepoComment struct {
+	ctx  *markup.RenderContext
+	opts RepoCommentOptions
+
+	commitChecker *commitChecker
+	repoLink      string
+}
+
+func (r *RepoComment) CleanUp() {
+	_ = r.commitChecker.Close()
+}
+
+func (r *RepoComment) IsCommitIDExisting(commitID string) bool {
+	return r.commitChecker.IsCommitIDExisting(commitID)
+}
+
+func (r *RepoComment) ResolveLink(link string, likeType markup.LinkType) (finalLink string) {
+	switch likeType {
+	case markup.LinkTypeApp:
+		finalLink = r.ctx.ResolveLinkApp(link)
+	default:
+		finalLink = r.ctx.ResolveLinkRelative(r.repoLink, r.opts.CurrentRefPath, link)
+	}
+	return finalLink
+}
+
+var _ markup.RenderHelper = (*RepoComment)(nil)
+
+type RepoCommentOptions struct {
+	DeprecatedRepoName  string // it is only a patch for the non-standard "markup" api
+	DeprecatedOwnerName string // it is only a patch for the non-standard "markup" api
+	CurrentRefPath      string // eg: "branch/main" or "commit/11223344"
+}
+
+func NewRenderContextRepoComment(ctx context.Context, repo *repo_model.Repository, opts ...RepoCommentOptions) *markup.RenderContext {
+	helper := &RepoComment{
+		repoLink: repo.Link(),
+		opts:     util.OptionalArg(opts),
+	}
+	rctx := markup.NewRenderContext(ctx)
+	helper.ctx = rctx
+	if repo != nil {
+		helper.repoLink = repo.Link()
+		helper.commitChecker = newCommitChecker(ctx, repo)
+		rctx = rctx.WithMetas(repo.ComposeMetas(ctx))
+	} else {
+		// this is almost dead code, only to pass the incorrect tests
+		helper.repoLink = fmt.Sprintf("%s/%s", helper.opts.DeprecatedOwnerName, helper.opts.DeprecatedRepoName)
+		rctx = rctx.WithMetas(map[string]string{
+			"user": helper.opts.DeprecatedOwnerName,
+			"repo": helper.opts.DeprecatedRepoName,
+
+			"markdownLineBreakStyle":       "comment",
+			"markupAllowShortIssuePattern": "true",
+		})
+	}
+	rctx = rctx.WithHelper(helper)
+	return rctx
+}

models/renderhelper/repo_comment_test.go

@@ -0,0 +1,76 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package renderhelper
+
+import (
+	"context"
+	"testing"
+
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unittest"
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/markup/markdown"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRepoComment(t *testing.T) {
+	unittest.PrepareTestEnv(t)
+
+	repo1 := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
+
+	t.Run("AutoLink", func(t *testing.T) {
+		rctx := NewRenderContextRepoComment(context.Background(), repo1).WithMarkupType(markdown.MarkupName)
+		rendered, err := markup.RenderString(rctx, `
+65f1bf27bc3bf70f64657658635e66094edbcb4d
+#1
+@user2
+`)
+		assert.NoError(t, err)
+		assert.Equal(t,
+			`<p><a href="/user2/repo1/commit/65f1bf27bc3bf70f64657658635e66094edbcb4d" rel="nofollow"><code>65f1bf27bc</code></a><br/>
+<a href="/user2/repo1/issues/1" class="ref-issue" rel="nofollow">#1</a><br/>
+<a href="/user2" rel="nofollow">@user2</a></p>
+`, rendered)
+	})
+
+	t.Run("AbsoluteAndRelative", func(t *testing.T) {
+		rctx := NewRenderContextRepoComment(context.Background(), repo1).WithMarkupType(markdown.MarkupName)
+
+		// It is Gitea's old behavior, the relative path is resolved to the repo path
+		// It is different from GitHub, GitHub resolves relative links to current page's path
+		rendered, err := markup.RenderString(rctx, `
+[/test](/test)
+[./test](./test)
+![/image](/image)
+![./image](./image)
+`)
+		assert.NoError(t, err)
+		assert.Equal(t,
+			`<p><a href="/user2/repo1/test" rel="nofollow">/test</a><br/>
+<a href="/user2/repo1/test" rel="nofollow">./test</a><br/>
+<a href="/user2/repo1/image" target="_blank" rel="nofollow noopener"><img src="/user2/repo1/image" alt="/image"/></a><br/>
+<a href="/user2/repo1/image" target="_blank" rel="nofollow noopener"><img src="/user2/repo1/image" alt="./image"/></a></p>
+`, rendered)
+	})
+
+	t.Run("WithCurrentRefPath", func(t *testing.T) {
+		rctx := NewRenderContextRepoComment(context.Background(), repo1, RepoCommentOptions{CurrentRefPath: "/commit/1234"}).
+			WithMarkupType(markdown.MarkupName)
+
+		// the ref path is only used to render commit message: a commit message is rendered at the commit page with its commit ID path
+		rendered, err := markup.RenderString(rctx, `
+[/test](/test)
+[./test](./test)
+![/image](/image)
+![./image](./image)
+`)
+		assert.NoError(t, err)
+		assert.Equal(t, `<p><a href="/user2/repo1/test" rel="nofollow">/test</a><br/>
+<a href="/user2/repo1/commit/1234/test" rel="nofollow">./test</a><br/>
+<a href="/user2/repo1/image" target="_blank" rel="nofollow noopener"><img src="/user2/repo1/image" alt="/image"/></a><br/>
+<a href="/user2/repo1/commit/1234/image" target="_blank" rel="nofollow noopener"><img src="/user2/repo1/commit/1234/image" alt="./image"/></a></p>
+`, rendered)
+	})
+}

models/renderhelper/repo_file.go

@@ -0,0 +1,77 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package renderhelper
+
+import (
+	"context"
+	"fmt"
+	"path"
+
+	repo_model "code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/util"
+)
+
+type RepoFile struct {
+	ctx  *markup.RenderContext
+	opts RepoFileOptions
+
+	commitChecker *commitChecker
+	repoLink      string
+}
+
+func (r *RepoFile) CleanUp() {
+	_ = r.commitChecker.Close()
+}
+
+func (r *RepoFile) IsCommitIDExisting(commitID string) bool {
+	return r.commitChecker.IsCommitIDExisting(commitID)
+}
+
+func (r *RepoFile) ResolveLink(link string, likeType markup.LinkType) string {
+	finalLink := link
+	switch likeType {
+	case markup.LinkTypeApp:
+		finalLink = r.ctx.ResolveLinkApp(link)
+	case markup.LinkTypeDefault:
+		finalLink = r.ctx.ResolveLinkRelative(path.Join(r.repoLink, "src", r.opts.CurrentRefPath), r.opts.CurrentTreePath, link)
+	case markup.LinkTypeRaw:
+		finalLink = r.ctx.ResolveLinkRelative(path.Join(r.repoLink, "raw", r.opts.CurrentRefPath), r.opts.CurrentTreePath, link)
+	case markup.LinkTypeMedia:
+		finalLink = r.ctx.ResolveLinkRelative(path.Join(r.repoLink, "media", r.opts.CurrentRefPath), r.opts.CurrentTreePath, link)
+	}
+	return finalLink
+}
+
+var _ markup.RenderHelper = (*RepoFile)(nil)
+
+type RepoFileOptions struct {
+	DeprecatedRepoName  string // it is only a patch for the non-standard "markup" api
+	DeprecatedOwnerName string // it is only a patch for the non-standard "markup" api
+
+	CurrentRefPath  string // eg: "branch/main"
+	CurrentTreePath string // eg: "path/to/file" in the repo
+}
+
+func NewRenderContextRepoFile(ctx context.Context, repo *repo_model.Repository, opts ...RepoFileOptions) *markup.RenderContext {
+	helper := &RepoFile{opts: util.OptionalArg(opts)}
+	rctx := markup.NewRenderContext(ctx)
+	helper.ctx = rctx
+	if repo != nil {
+		helper.repoLink = repo.Link()
+		helper.commitChecker = newCommitChecker(ctx, repo)
+		rctx = rctx.WithMetas(repo.ComposeDocumentMetas(ctx))
+	} else {
+		// this is almost dead code, only to pass the incorrect tests
+		helper.repoLink = fmt.Sprintf("%s/%s", helper.opts.DeprecatedOwnerName, helper.opts.DeprecatedRepoName)
+		rctx = rctx.WithMetas(map[string]string{
+			"user": helper.opts.DeprecatedOwnerName,
+			"repo": helper.opts.DeprecatedRepoName,
+
+			"markdownLineBreakStyle": "document",
+		})
+	}
+	rctx = rctx.WithHelper(helper)
+	return rctx
+}