From 0a971f057f3d29d62c7edafc5aa89becb684e080 Mon Sep 17 00:00:00 2001
From: Oleg Samarin <osamarin@openintegration.inc>
Date: Tue, 12 May 2026 11:54:15 +0300
Subject: [PATCH] Fixed markdown preview rendering indented code blocks outside
 their list item
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Fenced code blocks indented inside an ordered list item were rendered as
standalone <pre> elements between separate <ol> elements, causing:
- Wrong visual nesting (code block at left margin, not indented under its item)
- Ordered list numbering reset to 1 after each code block
- 4 extra leading spaces copied from the code block content

Fix: detect indented fences (preceding segment ends with whitespace) and
embed the <pre> inside the parent <li>, continuing the same <ol> for
subsequent list items. Top-level code blocks (no indent) still break the
list as expected. Added orderedListNumber() to emit <ol start="N"> so
any list — indented or top-level — renders from its written start number.
Added dedent() to strip common leading indentation from code block content.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 CHANGELOG.md                                  |  1 +
 pom.xml                                       |  2 +-
 .../ui/common/MarkdownRenderer.java           | 70 +++++++++++++++--
 .../ui/common/MarkdownRendererTest.java       | 77 ++++++++++++++++++-
 4 files changed, 137 insertions(+), 13 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6f489f73..5982a31c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,4 @@
+- Fixed markdown preview rendering fenced code blocks indented inside list items outside the list instead of nested within their list item
 - Fixed .md files in the Files panel losing all standard context menu items (Open, Cut, Copy, Delete, etc.) after installing the plugin — only "Preview Markdown" was shown
 - Fixed Bypass Permissions edit mode not suppressing the file diff dialog: the edit mode was lost from the registry because it was set before the working directory was assigned at session start
 
diff --git a/pom.xml b/pom.xml
index 436368b1..816fba30 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>io.github.nbclaudecodegui</groupId>
     <artifactId>netbeans-claude-code-gui</artifactId>
-    <version>0.22.51-SNAPSHOT</version>
+    <version>0.22.53-SNAPSHOT</version>
     <packaging>nbm</packaging>
     <name>Netbeans Plugin Claude Code GUI</name>
     <description>NetBeans plugin that provides a GUI for Claude Code CLI — run claude code sessions directly inside the IDE.</description>
diff --git a/src/main/java/io/github/nbclaudecodegui/ui/common/MarkdownRenderer.java b/src/main/java/io/github/nbclaudecodegui/ui/common/MarkdownRenderer.java
index ecfc8957..17e2906d 100644
--- a/src/main/java/io/github/nbclaudecodegui/ui/common/MarkdownRenderer.java
+++ b/src/main/java/io/github/nbclaudecodegui/ui/common/MarkdownRenderer.java
@@ -228,6 +228,7 @@ public static String toHtml(String markdown) {
         StringBuilder html = new StringBuilder();
         // Split on fenced code blocks; odd-indexed segments are code content.
         String[] parts = markdown.split("```[^\\n]*\\n", -1);
+        boolean continueList = false;
         for (int i = 0; i < parts.length; i++) {
             if (i % 2 == 0) {
                 // regular text segment
@@ -236,19 +237,46 @@ public static String toHtml(String markdown) {
                 if (i > 0 && seg.startsWith("```")) {
                     seg = seg.substring(3);
                 }
-                html.append(convertSegment(seg));
+                String converted = convertSegment(seg);
+                if (continueList) {
+                    // strip the new <ol start="N">...</ol> wrapper and continue inside the open list
+                    converted = converted.replaceFirst("^<ol start=\"\\d+\">", "")
+                                         .replaceFirst("</ol>$", "");
+                    continueList = false;
+                    html.append(converted).append("</ol>");
+                } else {
+                    html.append(converted);
+                }
             } else {
-                // code block content (strip trailing ```)
+                // code block content
                 String code = parts[i];
                 if (code.endsWith("```")) {
                     code = code.substring(0, code.length() - 3);
                 }
-                if (code.endsWith("\n")) {
-                    code = code.substring(0, code.length() - 1);
+                code = code.stripTrailing();
+                code = dedent(code);
+                String preHtml = "<pre>" + esc(code) + "</pre>";
+                // An indented fence (spaces before ```) means the code block belongs to a list item
+                boolean indented = i > 0 && parts[i - 1].matches("(?s).*[ \t]+$");
+                if (indented) {
+                    // Remove the list closure emitted by the previous segment, then
+                    // embed the code block inside the last <li> before re-closing it.
+                    if (html.toString().endsWith("</ol>")) {
+                        html.delete(html.length() - 5, html.length());
+                    }
+                    if (html.toString().endsWith("</li>")) {
+                        html.delete(html.length() - 5, html.length());
+                    }
+                    html.append(preHtml).append("</li>");
+                    continueList = true;
+                } else {
+                    html.append(preHtml);
                 }
-                html.append("<pre>").append(esc(code)).append("</pre>");
             }
         }
+        if (continueList) {
+            html.append("</ol>");
+        }
         return html.toString();
     }
 
@@ -533,13 +561,13 @@ private static int renderNestedList(String[] lines, int start, StringBuilder htm
             boolean ordered = isOrdered(line);
 
             if (indentStack.isEmpty()) {
-                html.append(ordered ? "<ol>" : "<ul>");
+                html.append(ordered ? "<ol start=\"" + orderedListNumber(line) + "\">" : "<ul>");
                 indentStack.add(indent);
                 typeStack.add(ordered);
             } else {
                 int topIndent = indentStack.get(indentStack.size() - 1);
                 if (indent > topIndent) {
-                    html.append(ordered ? "<ol>" : "<ul>");
+                    html.append(ordered ? "<ol start=\"" + orderedListNumber(line) + "\">" : "<ul>");
                     indentStack.add(indent);
                     typeStack.add(ordered);
                 } else if (indent < topIndent) {
@@ -552,7 +580,7 @@ private static int renderNestedList(String[] lines, int start, StringBuilder htm
                 if (!typeStack.isEmpty() && typeStack.get(typeStack.size() - 1) != ordered) {
                     html.append(typeStack.get(typeStack.size() - 1) ? "</ol>" : "</ul>");
                     typeStack.set(typeStack.size() - 1, ordered);
-                    html.append(ordered ? "<ol>" : "<ul>");
+                    html.append(ordered ? "<ol start=\"" + orderedListNumber(line) + "\">" : "<ul>");
                 }
             }
 
@@ -573,5 +601,31 @@ private static int leadingSpaces(String line) {
         return n;
     }
 
+    private static int orderedListNumber(String line) {
+        java.util.regex.Matcher m =
+                java.util.regex.Pattern.compile("^\\s*(\\d+)\\.\\s+").matcher(line);
+        return m.find() ? Integer.parseInt(m.group(1)) : 1;
+    }
+
+    private static String dedent(String code) {
+        String[] lines = code.split("\n", -1);
+        int min = Integer.MAX_VALUE;
+        for (String l : lines) {
+            if (!l.isBlank()) {
+                int sp = 0;
+                while (sp < l.length() && l.charAt(sp) == ' ') sp++;
+                min = Math.min(min, sp);
+            }
+        }
+        if (min == 0 || min == Integer.MAX_VALUE) return code;
+        StringBuilder sb = new StringBuilder();
+        for (int k = 0; k < lines.length; k++) {
+            String l = lines[k];
+            sb.append(l.length() >= min ? l.substring(min) : l);
+            if (k < lines.length - 1) sb.append('\n');
+        }
+        return sb.toString();
+    }
+
     private MarkdownRenderer() {}
 }
diff --git a/src/test/java/io/github/nbclaudecodegui/ui/common/MarkdownRendererTest.java b/src/test/java/io/github/nbclaudecodegui/ui/common/MarkdownRendererTest.java
index 0ea16901..84d8772b 100644
--- a/src/test/java/io/github/nbclaudecodegui/ui/common/MarkdownRendererTest.java
+++ b/src/test/java/io/github/nbclaudecodegui/ui/common/MarkdownRendererTest.java
@@ -89,7 +89,7 @@ void testUnorderedList() {
     @Test
     void testOrderedList() {
         String html = MarkdownRenderer.toHtml("1. first\n2. second");
-        assertTrue(html.contains("<ol>"),  "ol open");
+        assertTrue(html.contains("<ol start=\"1\">"),  "ol open");
         assertTrue(html.contains("<li>first</li>"),  "item first");
         assertTrue(html.contains("<li>second</li>"), "item second");
     }
@@ -275,8 +275,8 @@ void testNestedOrderedList() {
         String md = "1. first\n    1. sub-first\n    2. sub-second\n2. second";
         String html = MarkdownRenderer.toHtml(md);
         // outer ol must contain an inner ol
-        int outerOl = html.indexOf("<ol>");
-        int innerOl = html.indexOf("<ol>", outerOl + 1);
+        int outerOl = html.indexOf("<ol start=");
+        int innerOl = html.indexOf("<ol start=", outerOl + 1);
         assertTrue(innerOl > outerOl, "inner <ol> must exist inside outer <ol>");
         assertTrue(html.contains("<li>first</li>") || html.contains("<li>first"),
                 "outer first item");
@@ -304,7 +304,7 @@ void testNestedUnorderedList() {
     void testMixedNestedList() {
         String md = "1. item\n    - nested-ul\n2. item2";
         String html = MarkdownRenderer.toHtml(md);
-        assertTrue(html.contains("<ol>"), "outer ol");
+        assertTrue(html.contains("<ol start=\"1\">"), "outer ol");
         assertTrue(html.contains("<ul>"), "inner ul");
         assertTrue(html.contains("nested-ul"), "nested item text");
     }
@@ -354,4 +354,73 @@ void testResolveImagePathsWindowsBackslashesNormalized() {
         String result = MarkdownRenderer.resolveImagePaths(html, "C:\\docs\\project");
         assertEquals("<img src=\"file://C:/docs/project/img.png\" alt=\"\">", result);
     }
+
+    // -------------------------------------------------------------------------
+    // Ordered list numbering after code blocks
+    // -------------------------------------------------------------------------
+
+    @Test
+    void testOrderedListExplicitStartAttribute() {
+        // A list starting at 3 must emit <ol start="3">
+        String html = MarkdownRenderer.toHtml("3. Third\n4. Fourth\n");
+        assertTrue(html.contains("<ol start=\"3\">"),
+                "Expected <ol start=\"3\"> but got: " + html);
+    }
+
+    @Test
+    void testIndentedCodeBlockDoesNotResetNumbering() {
+        // Code block indented inside a list item — both items must be in ONE <ol start="1">
+        String md = "1. Item one\n\n    ```bash\n    code\n    ```\n\n2. Item two\n";
+        String html = MarkdownRenderer.toHtml(md);
+        // Only one <ol> should exist; items continue in the same list
+        int firstOl = html.indexOf("<ol ");
+        int secondOl = html.indexOf("<ol ", firstOl + 1);
+        assertEquals(-1, secondOl,
+                "Indented code block must not start a new <ol>; got: " + html);
+        assertTrue(html.contains("Item one") && html.contains("Item two"),
+                "Both items must be present: " + html);
+    }
+
+    @Test
+    void testIndentedCodeBlockInsideLi() {
+        // <pre> must be inside <li>, not between two separate <ol> elements
+        String md = "1. Item one\n\n    ```bash\n    code here\n    ```\n\n2. Item two\n";
+        String html = MarkdownRenderer.toHtml(md);
+        // </li> must not appear before <pre>
+        int liClose = html.indexOf("</li>");
+        int preOpen = html.indexOf("<pre>");
+        assertTrue(preOpen > 0, "Expected <pre> in: " + html);
+        assertTrue(preOpen < liClose,
+                "<pre> must appear before the first </li>; got: " + html);
+    }
+
+    @Test
+    void testTopLevelCodeBlockResetsNumbering() {
+        // Top-level code block between two lists — second list starts at 1
+        String md = "1. Item A\n\n```\ntop level\n```\n\n1. New list\n";
+        String html = MarkdownRenderer.toHtml(md);
+        long count = html.chars().filter(c -> c == '1')
+                .count(); // rough: just assert no <ol start="2"> for the second list
+        assertFalse(html.contains("<ol start=\"2\">"),
+                "Top-level code block should reset numbering; must not have <ol start=\"2\"> but got: " + html);
+    }
+
+    // -------------------------------------------------------------------------
+    // Indented code block — no leading spaces in <pre>
+    // -------------------------------------------------------------------------
+
+    @Test
+    void testIndentedFencedCodeBlockNoLeadingSpaces() {
+        String md = "1. Item\n\n    ```bash\n    mkdir foo\n    ```\n\n2. Done\n";
+        String html = MarkdownRenderer.toHtml(md);
+        // Extract <pre> content and verify no leading spaces
+        int preStart = html.indexOf("<pre>") + "<pre>".length();
+        int preEnd = html.indexOf("</pre>");
+        assertTrue(preStart > 0 && preEnd > preStart, "Expected <pre> block in: " + html);
+        String preContent = html.substring(preStart, preEnd);
+        assertFalse(preContent.startsWith(" "),
+                "Code block content must not start with spaces but got: [" + preContent + "]");
+        assertTrue(preContent.contains("mkdir foo"),
+                "Code block must contain the command: " + preContent);
+    }
 }