fix: avoid markup render panic (#38698)

fix #38697

The root problem is that "commitChecker.repo" can be nil when the render
is called without a real repo.

models/renderhelper/commit_checker.go

@@ -13,35 +13,38 @@ import (
 )
 
 type commitChecker struct {
-	ctx         context.Context
-	commitCache map[string]bool
-	repo        *repo_model.Repository
+	ctx          context.Context
+	commitCache  map[string]bool
+	repoOptional *repo_model.Repository
 
 	gitRepo       *git.Repository
 	gitRepoCloser io.Closer
 }
 
 func newCommitChecker(ctx context.Context, repo *repo_model.Repository) *commitChecker {
-	return &commitChecker{ctx: ctx, commitCache: make(map[string]bool), repo: repo}
+	return &commitChecker{ctx: ctx, commitCache: make(map[string]bool), repoOptional: repo}
 }
 
 func (c *commitChecker) Close() error {
-	if c != nil && c.gitRepoCloser != nil {
+	if c.gitRepoCloser != nil {
 		return c.gitRepoCloser.Close()
 	}
 	return nil
 }
 
 func (c *commitChecker) IsCommitIDExisting(commitID string) bool {
+	if c.repoOptional == nil {
+		return false
+	}
 	exist, inCache := c.commitCache[commitID]
 	if inCache {
 		return exist
 	}
 
 	if c.gitRepo == nil {
-		r, closer, err := git.RepositoryFromContextOrOpen(c.ctx, c.repo)
+		r, closer, err := git.RepositoryFromContextOrOpen(c.ctx, c.repoOptional)
 		if err != nil {
-			log.Error("Unable to open repository: %s, error: %v", c.repo.FullName(), err)
+			log.Error("Unable to open repository: %s, error: %v", c.repoOptional.FullName(), err)
 			return false
 		}
 		c.gitRepo, c.gitRepoCloser = r, closer

models/renderhelper/repo_comment.go

@@ -51,10 +51,10 @@ func NewRenderContextRepoComment(ctx context.Context, repo *repo_model.Repositor
 	helper := &RepoComment{opts: util.OptionalArg(opts)}
 	rctx := markup.NewRenderContext(ctx)
 	helper.ctx = rctx
+	helper.commitChecker = newCommitChecker(ctx, repo)
 	var metas map[string]string
 	if repo != nil {
 		helper.repoLink = repo.Link()
-		helper.commitChecker = newCommitChecker(ctx, repo)
 		metas = repo.ComposeCommentMetas(ctx)
 	} else {
 		// repo can be nil when rendering a commit message in user's dashboard feedback whose repository has been deleted

models/renderhelper/repo_file.go

@@ -58,9 +58,9 @@ func NewRenderContextRepoFile(ctx context.Context, repo *repo_model.Repository,
 	helper := &RepoFile{opts: util.OptionalArg(opts)}
 	rctx := markup.NewRenderContext(ctx)
 	helper.ctx = rctx
+	helper.commitChecker = newCommitChecker(ctx, repo)
 	if repo != nil {
 		helper.repoLink = repo.Link()
-		helper.commitChecker = newCommitChecker(ctx, repo)
 		rctx = rctx.WithMetas(repo.ComposeRepoFileMetas(ctx))
 	} else {
 		// this is almost dead code, only to pass the incorrect tests

models/renderhelper/repo_wiki.go

@@ -57,9 +57,9 @@ type RepoWikiOptions struct {
 func NewRenderContextRepoWiki(ctx context.Context, repo *repo_model.Repository, opts ...RepoWikiOptions) *markup.RenderContext {
 	helper := &RepoWiki{opts: util.OptionalArg(opts)}
 	rctx := markup.NewRenderContext(ctx).WithMarkupType(markdown.MarkupName)
+	helper.commitChecker = newCommitChecker(ctx, repo)
 	if repo != nil {
 		helper.repoLink = repo.Link()
-		helper.commitChecker = newCommitChecker(ctx, repo)
 		rctx = rctx.WithMetas(repo.ComposeWikiMetas(ctx))
 	} else {
 		// this is almost dead code, only to pass the incorrect tests

routers/api/v1/misc/markup_test.go

@@ -177,49 +177,34 @@ Here are some links to the most important topics. You can find the full list of
 	testRenderMarkup(t, "unknown", false, "", "## Test", "unsupported render mode: unknown\n", http.StatusUnprocessableEntity)
 }
 
-var simpleCases = []string{
-	// Guard wiki sidebar: special syntax
-	`[[Guardfile-DSL / Configuring-Guard|Guardfile-DSL---Configuring-Guard]]`,
-	// rendered
-	`<p>[[Guardfile-DSL / Configuring-Guard|Guardfile-DSL---Configuring-Guard]]</p>
-`,
-	// special syntax
-	`[[Name|Link]]`,
-	// rendered
-	`<p>[[Name|Link]]</p>
-`,
-	// empty
-	``,
-	// rendered
-	``,
-}
-
 func TestAPI_RenderSimple(t *testing.T) {
 	setting.AppURL = AppURL
 	markup.RenderBehaviorForTesting.DisableAdditionalAttributes = true
-	options := api.MarkdownOption{
-		Mode:    "markdown",
-		Text:    "",
-		Context: "/user2/repo1",
-	}
-	ctx, resp := contexttest.MockAPIContext(t, "POST /api/v1/markdown")
-	for i := 0; i < len(simpleCases); i += 2 {
-		options.Text = simpleCases[i]
-		web.SetForm(ctx, &options)
-		Markdown(ctx)
-		assert.Equal(t, simpleCases[i+1], resp.Body.String())
-		resp.Body.Reset()
-	}
-}
 
-func TestAPI_RenderRaw(t *testing.T) {
-	setting.AppURL = AppURL
-	markup.RenderBehaviorForTesting.DisableAdditionalAttributes = true
-	ctx, resp := contexttest.MockAPIContext(t, "POST /api/v1/markdown")
-	for i := 0; i < len(simpleCases); i += 2 {
-		ctx.Req.Body = io.NopCloser(strings.NewReader(simpleCases[i]))
-		MarkdownRaw(ctx)
-		assert.Equal(t, simpleCases[i+1], resp.Body.String())
-		resp.Body.Reset()
+	testCases := []struct {
+		in, out string
+		mode    string
+	}{
+		{in: "", out: ""},
+		{in: "[[special-syntax]]", out: "<p>[[special-syntax]]</p>\n", mode: "markdown"},
+		{in: "[[special|syntax]]", out: "<p>[[special|syntax]]</p>\n", mode: "markdown"},
+		{in: "01234567890123456789", out: "<p>01234567890123456789</p>\n", mode: "gfm"}, // commit-like content should not crash the render
 	}
+	t.Run("markdown", func(t *testing.T) {
+		for _, c := range testCases {
+			options := api.MarkdownOption{Mode: c.mode, Text: c.in, Context: "/user2/repo1"}
+			ctx, resp := contexttest.MockAPIContext(t, "POST /api/v1/markdown")
+			web.SetForm(ctx, &options)
+			Markdown(ctx)
+			assert.Equal(t, c.out, resp.Body.String())
+		}
+	})
+	t.Run("markdown-raw", func(t *testing.T) {
+		for _, c := range testCases {
+			ctx, resp := contexttest.MockAPIContext(t, "POST /api/v1/markdown")
+			ctx.Req.Body = io.NopCloser(strings.NewReader(c.in))
+			MarkdownRaw(ctx)
+			assert.Equal(t, c.out, resp.Body.String())
+		}
+	})
 }