From a97529d7afdbb8eb04c98700a31d8cf79fc6e630 Mon Sep 17 00:00:00 2001
From: davotoula <david.kaspar@gmail.com>
Date: Tue, 23 Jun 2026 18:13:19 +0200
Subject: [PATCH] fix: detect markdown when a heading/list follows a blank line

isMarkdown() treated the second newline of a blank line as a non-space
character, flipping the line-start tracker off. ATX headings, blockquotes,
and list markers that follow the standard blank-line spacing went
undetected, so NIP-23 long-form articles made of prose plus section
headings rendered as raw text. Exclude newline/carriage-return from the
line-start guard so a blank line stays at line start.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 .../amethyst/service/CachedRichTextParser.kt  |  9 ++++-
 .../CachedRichTextParserMarkdownTest.kt       | 40 +++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/amethyst/src/main/java/com/vitorpamplona/amethyst/service/CachedRichTextParser.kt b/amethyst/src/main/java/com/vitorpamplona/amethyst/service/CachedRichTextParser.kt
index 7a401f57b8..ea4dfc2402 100644
--- a/amethyst/src/main/java/com/vitorpamplona/amethyst/service/CachedRichTextParser.kt
+++ b/amethyst/src/main/java/com/vitorpamplona/amethyst/service/CachedRichTextParser.kt
@@ -207,7 +207,14 @@ object CachedRichTextParser {
             // checks that need to know "how much non-space text has
             // appeared on the current line".
             if (isNewLine) {
-                if (c != ' ' && c != '\t') {
+                // A blank line is still "at line start": skipping '\n'/'\r'
+                // here keeps isNewLine true so a heading/blockquote/list
+                // marker on the next line (the standard `\n\n#` spacing) is
+                // still recognized as line-leading. Without the newline
+                // exclusion, the second '\n' of a blank line flipped
+                // isNewLine to false and ATX headings after a blank line
+                // went undetected.
+                if (c != ' ' && c != '\t' && c != '\n' && c != '\r') {
                     isNewLine = false
                     nonSpaceCharCountOnLine = 1
                     lastNonSpaceChar = c
diff --git a/amethyst/src/test/java/com/vitorpamplona/amethyst/CachedRichTextParserMarkdownTest.kt b/amethyst/src/test/java/com/vitorpamplona/amethyst/CachedRichTextParserMarkdownTest.kt
index 7f5c78ba4d..366e7e322e 100644
--- a/amethyst/src/test/java/com/vitorpamplona/amethyst/CachedRichTextParserMarkdownTest.kt
+++ b/amethyst/src/test/java/com/vitorpamplona/amethyst/CachedRichTextParserMarkdownTest.kt
@@ -68,6 +68,46 @@ class CachedRichTextParserMarkdownTest {
 
     @Test fun atxAfterNewlineIsMarkdown() = assertTrue(CachedRichTextParser.isMarkdown("intro\n# Heading"))
 
+    // ---- Line-leading markers after a BLANK line ------------------------
+    // Regression: the standard `\n\n#` spacing (a blank line before a
+    // heading) was undetected because the blank line's second '\n' flipped
+    // the line-start tracker off. NIP-23 long-form articles that are pure
+    // prose plus `## Section` headings rendered as raw text as a result.
+
+    @Test fun atxAfterBlankLineIsMarkdown() = assertTrue(CachedRichTextParser.isMarkdown("intro\n\n# Heading"))
+
+    @Test fun atxH3AfterBlankLineIsMarkdown() = assertTrue(CachedRichTextParser.isMarkdown("intro\n\n### Heading"))
+
+    @Test fun atxAfterMultipleBlankLinesIsMarkdown() = assertTrue(CachedRichTextParser.isMarkdown("intro\n\n\n\n## Heading"))
+
+    @Test fun atxAfterCrlfBlankLineIsMarkdown() = assertTrue(CachedRichTextParser.isMarkdown("intro\r\n\r\n## Heading"))
+
+    @Test fun blockquoteAfterBlankLineIsMarkdown() = assertTrue(CachedRichTextParser.isMarkdown("intro\n\n> quoted"))
+
+    @Test fun bulletAfterBlankLineIsMarkdown() = assertTrue(CachedRichTextParser.isMarkdown("intro\n\n- item"))
+
+    @Test fun orderedListAfterBlankLineIsMarkdown() = assertTrue(CachedRichTextParser.isMarkdown("intro\n\n1. first"))
+
+    @Test
+    fun proseArticleWithHeadingAfterBlankLineIsMarkdown() =
+        assertTrue(
+            CachedRichTextParser.isMarkdown(
+                "The cryptographic part of commerce has been solved.\n\n" +
+                    "What follows is a history.\n\n" +
+                    "### The merchant posts of the Hansa\n\n" +
+                    "Long before any king claimed a monopoly on letters.",
+            ),
+        )
+
+    // Blank lines alone must NOT promote ordinary prose to markdown.
+    @Test
+    fun plainProseWithBlankLinesIsNotMarkdown() =
+        assertFalse(
+            CachedRichTextParser.isMarkdown(
+                "Just a normal sentence.\n\nAnother paragraph with no markdown at all.",
+            ),
+        )
+
     // ---- Blockquote -----------------------------------------------------
 
     @Test fun blockquoteIsMarkdown() = assertTrue(CachedRichTextParser.isMarkdown("> a quote"))