Prevent panic in Org mode HighlightCodeBlock (#17140)

When rendering source in org mode there is a mistake in the highlight code that
causes a panic.

This PR fixes this.

Fix #17139

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

diff --git a/modules/highlight/highlight.go b/modules/highlight/highlight.go
index 079f7a44bd111d39c83067bf47295e488a30de7d..6684fbe842910a8b693995e3e487c80e0f60b318 100644 (file)
--- a/modules/highlight/highlight.go
+++ b/modules/highlight/highlight.go
@@ -66,17 +66,6 @@ func Code(fileName, code string) string {
        if len(code) > sizeLimit {
                return code
        }
-       formatter := html.New(html.WithClasses(true),
-               html.WithLineNumbers(false),
-               html.PreventSurroundingPre(true),
-       )
-       if formatter == nil {
-               log.Error("Couldn't create chroma formatter")
-               return code
-       }
-
-       htmlbuf := bytes.Buffer{}
-       htmlw := bufio.NewWriter(&htmlbuf)
 
        var lexer chroma.Lexer
        if val, ok := highlightMapping[filepath.Ext(fileName)]; ok {
@@ -97,6 +86,18 @@ func Code(fileName, code string) string {
                }
                cache.Add(fileName, lexer)
        }
+       return CodeFromLexer(lexer, code)
+}
+
+// CodeFromLexer returns a HTML version of code string with chroma syntax highlighting classes
+func CodeFromLexer(lexer chroma.Lexer, code string) string {
+       formatter := html.New(html.WithClasses(true),
+               html.WithLineNumbers(false),
+               html.PreventSurroundingPre(true),
+       )
+
+       htmlbuf := bytes.Buffer{}
+       htmlw := bufio.NewWriter(&htmlbuf)
 
        iterator, err := lexer.Tokenise(nil, string(code))
        if err != nil {

diff --git a/modules/markup/orgmode/orgmode.go b/modules/markup/orgmode/orgmode.go
index 7e9f1f45c5a7a3901b1c9283ac24426aed272d75..b035e04a1fccaa7b4cd9cfed0ed3fa31395e6819 100644 (file)
--- a/modules/markup/orgmode/orgmode.go
+++ b/modules/markup/orgmode/orgmode.go
@@ -12,6 +12,7 @@ import (
        "strings"
 
        "code.gitea.io/gitea/modules/highlight"
+       "code.gitea.io/gitea/modules/log"
        "code.gitea.io/gitea/modules/markup"
        "code.gitea.io/gitea/modules/setting"
        "code.gitea.io/gitea/modules/util"
@@ -51,6 +52,12 @@ func (Renderer) SanitizerRules() []setting.MarkupSanitizerRule {
 func Render(ctx *markup.RenderContext, input io.Reader, output io.Writer) error {
        htmlWriter := org.NewHTMLWriter()
        htmlWriter.HighlightCodeBlock = func(source, lang string, inline bool) string {
+               defer func() {
+                       if err := recover(); err != nil {
+                               log.Error("Panic in HighlightCodeBlock: %v\n%s", err, log.Stack(2))
+                               panic(err)
+                       }
+               }()
                var w strings.Builder
                if _, err := w.WriteString(`<pre>`); err != nil {
                        return ""
@@ -80,7 +87,7 @@ func Render(ctx *markup.RenderContext, input io.Reader, output io.Writer) error
                        }
                        lexer = chroma.Coalesce(lexer)
 
-                       if _, err := w.WriteString(highlight.Code(lexer.Config().Filenames[0], source)); err != nil {
+                       if _, err := w.WriteString(highlight.CodeFromLexer(lexer, source)); err != nil {
                                return ""
                        }
                }

diff --git a/modules/markup/orgmode/orgmode_test.go b/modules/markup/orgmode/orgmode_test.go
index da89326e9e13e48576862e448dd059b30ba2484b..81d0d66a76c5be5a3315cf0be5cc2f3ab0f155f7 100644 (file)
--- a/modules/markup/orgmode/orgmode_test.go
+++ b/modules/markup/orgmode/orgmode_test.go
@@ -57,3 +57,29 @@ func TestRender_Images(t *testing.T) {
        test("[[file:"+url+"]]",
                "<p><img src=\""+result+"\" alt=\""+result+"\" title=\""+result+"\" /></p>")
 }
+
+func TestRender_Source(t *testing.T) {
+       setting.AppURL = AppURL
+       setting.AppSubURL = AppSubURL
+
+       test := func(input, expected string) {
+               buffer, err := RenderString(&markup.RenderContext{
+                       URLPrefix: setting.AppSubURL,
+               }, input)
+               assert.NoError(t, err)
+               assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(buffer))
+       }
+
+       test(`#+begin_src go
+// HelloWorld prints "Hello World"
+func HelloWorld() {
+       fmt.Println("Hello World")
+}
+#+end_src
+`, `<div class="src src-go">
+<pre><code class="chroma language-go"><span class="c1">// HelloWorld prints &#34;Hello World&#34;
+</span><span class="c1"></span><span class="kd">func</span> <span class="nf">HelloWorld</span><span class="p">()</span> <span class="p">{</span>
+       <span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">&#34;Hello World&#34;</span><span class="p">)</span>
+<span class="p">}</span></code></pre>
+</div>`)
+}