fix(ios): preserve assistant line breaks in chat

qingminglong · qingminglong · commit 92531758b308 · 2026-06-30T14:19:54.000+08:00
diff --git a/apps/shared/OpenClawKit/Sources/OpenClawChatUI/ChatMarkdownPreprocessor.swift b/apps/shared/OpenClawKit/Sources/OpenClawChatUI/ChatMarkdownPreprocessor.swift
@@ -220,4 +220,58 @@ enum ChatMarkdownPreprocessor {
         output = output.replacingOccurrences(of: "\n\n\n", with: "\n\n")
         return output.trimmingCharacters(in: .whitespacesAndNewlines)
     }
+
+    static func markdownForRendering(_ raw: String) -> String {
+        let lines = raw.split(separator: "\n", omittingEmptySubsequences: false).map(String.init)
+        var fenceMarker: Character?
+        var fenceLength = 0
+        var output: [String] = []
+
+        for index in lines.indices {
+            let line = lines[index]
+            let trimmed = line.trimmingCharacters(in: .whitespaces)
+            let next = index + 1 < lines.count ? lines[index + 1] : nil
+            let nextTrimmed = next?.trimmingCharacters(in: .whitespaces) ?? ""
+            if let fence = self.fenceBoundary(in: line) {
+                if let currentMarker = fenceMarker {
+                    if fence.marker == currentMarker, fence.count >= fenceLength, !fence.hasTrailingContent {
+                        fenceMarker = nil
+                        fenceLength = 0
+                    }
+                } else {
+                    fenceMarker = fence.marker
+                    fenceLength = fence.count
+                }
+                output.append(line)
+                continue
+            }
+            if fenceMarker != nil ||
+                line.hasPrefix("    ") ||
+                line.hasPrefix("\t") ||
+                trimmed.isEmpty ||
+                next == nil ||
+                nextTrimmed.isEmpty ||
+                self.fenceBoundary(in: next ?? "") != nil ||
+                line.hasSuffix("  ") ||
+                line.hasSuffix("\\")
+            {
+                output.append(line)
+                continue
+            }
+            output.append("\(line)  ")
+        }
+
+        return output.joined(separator: "\n")
+    }
+
+    private static func fenceBoundary(in line: String) -> (marker: Character, count: Int, hasTrailingContent: Bool)? {
+        let leadingSpaces = line.prefix { $0 == " " }.count
+        guard leadingSpaces < 4, !line.hasPrefix("\t") else { return nil }
+        let trimmed = line.trimmingCharacters(in: .whitespaces)
+        guard let marker = trimmed.first, marker == "`" || marker == "~" else { return nil }
+        let markerCount = trimmed.prefix { $0 == marker }.count
+        guard markerCount >= 3 else { return nil }
+        let remaining = trimmed.dropFirst(markerCount).trimmingCharacters(in: .whitespaces)
+        return (marker: marker, count: markerCount, hasTrailingContent: !remaining.isEmpty)
+    }
 }
diff --git a/apps/shared/OpenClawKit/Sources/OpenClawChatUI/ChatMarkdownRenderer.swift b/apps/shared/OpenClawKit/Sources/OpenClawChatUI/ChatMarkdownRenderer.swift
@@ -40,10 +40,11 @@ struct ChatMarkdownRenderer: View {
     }
 
     private func markdownText(_ markdown: String) -> AttributedString {
+        let renderMarkdown = ChatMarkdownPreprocessor.markdownForRendering(markdown)
         let options = AttributedString.MarkdownParsingOptions(
             interpretedSyntax: .full,
             failurePolicy: .returnPartiallyParsedIfPossible)
-        return (try? AttributedString(markdown: markdown, options: options)) ?? AttributedString(markdown)
+        return (try? AttributedString(markdown: renderMarkdown, options: options)) ?? AttributedString(markdown)
     }
 }
 
diff --git a/apps/shared/OpenClawKit/Tests/OpenClawKitTests/ChatMarkdownPreprocessorTests.swift b/apps/shared/OpenClawKit/Tests/OpenClawKitTests/ChatMarkdownPreprocessorTests.swift
@@ -150,6 +150,91 @@ struct ChatMarkdownPreprocessorTests {
         #expect(result.cleaned == "Hello there\nActual message")
     }
 
+    @Test func keepsCleanedTextPlainWhenInputHasSingleLineBreaks() {
+        let markdown = """
+        First line
+        Second line
+
+        Third paragraph
+        """
+
+        let result = ChatMarkdownPreprocessor.preprocess(markdown: markdown)
+
+        #expect(result.cleaned == "First line\nSecond line\n\nThird paragraph")
+    }
+
+    @Test func addsMarkdownHardBreaksForVisibleSingleLineRendering() {
+        let markdown = """
+        First line
+        Second line
+
+        Third paragraph
+        """
+
+        let result = ChatMarkdownPreprocessor.markdownForRendering(markdown)
+
+        #expect(result == "First line  \nSecond line\n\nThird paragraph")
+    }
+
+    @Test func leavesFencedCodeLineBreaksUntouchedForRendering() {
+        let markdown = """
+        Before
+        ```text
+        alpha
+        beta
+        ```
+        After
+        """
+
+        let result = ChatMarkdownPreprocessor.markdownForRendering(markdown)
+
+        #expect(result == "Before\n```text\nalpha\nbeta\n```\nAfter")
+    }
+
+    @Test func leavesTildeFencedCodeLineBreaksUntouchedForRendering() {
+        let markdown = """
+        Before
+        ~~~text
+        alpha
+        beta
+        ~~~
+        After
+        """
+
+        let result = ChatMarkdownPreprocessor.markdownForRendering(markdown)
+
+        #expect(result == "Before\n~~~text\nalpha\nbeta\n~~~\nAfter")
+    }
+
+    @Test func leavesIndentedCodeLineBreaksUntouchedForRendering() {
+        let markdown = """
+        Before
+            alpha
+            beta
+        After
+        """
+
+        let result = ChatMarkdownPreprocessor.markdownForRendering(markdown)
+
+        #expect(result == "Before  \n    alpha\n    beta\nAfter")
+    }
+
+    @Test func leavesShorterFenceTextInsideLongFenceUntouchedForRendering() {
+        let markdown = """
+        Before
+        ````markdown
+        ```text
+        alpha
+        ```
+        ````
+        After
+        """
+
+        let result = ChatMarkdownPreprocessor.markdownForRendering(markdown)
+
+        #expect(result == "Before\n````markdown\n```text\nalpha\n```\n````\nAfter")
+    }
+
     @Test func stripsTrailingUntrustedContextSuffix() {
         let markdown = """
         User-visible text

Original file line number	Diff line number	Diff line change
`@@ -40,10 +40,11 @@ struct ChatMarkdownRenderer: View {`
`40`	`40`	`}`
`41`	`41`
`42`	`42`	`private func markdownText(_ markdown: String) -> AttributedString {`
	`43`	`+ let renderMarkdown = ChatMarkdownPreprocessor.markdownForRendering(markdown)`
`43`	`44`	`let options = AttributedString.MarkdownParsingOptions(`
`44`	`45`	`interpretedSyntax: .full,`
`45`	`46`	`failurePolicy: .returnPartiallyParsedIfPossible)`
`46`		`- return (try? AttributedString(markdown: markdown, options: options)) ?? AttributedString(markdown)`
	`47`	`+ return (try? AttributedString(markdown: renderMarkdown, options: options)) ?? AttributedString(markdown)`
`47`	`48`	`}`
`48`	`49`	`}`
`49`	`50`