fix(vcs): preserve batched patch boundaries (#25787)

packages/ui/src/components/session-diff.test.ts

@@ -34,4 +34,20 @@ describe("session diff", () => {
     expect(text(view, "deletions")).toBe("one\n")
     expect(text(view, "additions")).toBe("two\n")
   })
+
+  test("ignores malformed persisted patches", () => {
+    const diff = {
+      file: "a.ts",
+      patch:
+        "diff --git a/a.ts b/a.ts\nindex ff4ceb2..65a1de0 100644\n--- a/a.ts\n+++ b/a.ts\n@@ -1,3 +1,3 @@\n keep\n+add\n same\r",
+      additions: 1,
+      deletions: 1,
+      status: "modified" as const,
+    }
+    const view = normalize(diff)
+
+    expect(view.patch).toBe(diff.patch)
+    expect(text(view, "deletions")).toBe("")
+    expect(text(view, "additions")).toBe("")
+  })
 })

packages/ui/src/components/session-diff.ts

@@ -27,26 +27,29 @@ const cache = new Map<string, FileDiffMetadata>()
 
 function patch(diff: ReviewDiff) {
   if (typeof diff.patch === "string") {
-    const [patch] = parsePatch(diff.patch)
+    try {
+      const [patch] = parsePatch(diff.patch)
+      const beforeLines = []
+      const afterLines = []
 
-    const beforeLines = []
-    const afterLines = []
-
-    for (const hunk of patch.hunks) {
-      for (const line of hunk.lines) {
-        if (line.startsWith("-")) {
-          beforeLines.push(line.slice(1))
-        } else if (line.startsWith("+")) {
-          afterLines.push(line.slice(1))
-        } else {
-          // context line (starts with ' ')
-          beforeLines.push(line.slice(1))
-          afterLines.push(line.slice(1))
+      for (const hunk of patch.hunks) {
+        for (const line of hunk.lines) {
+          if (line.startsWith("-")) {
+            beforeLines.push(line.slice(1))
+          } else if (line.startsWith("+")) {
+            afterLines.push(line.slice(1))
+          } else {
+            // context line (starts with ' ')
+            beforeLines.push(line.slice(1))
+            afterLines.push(line.slice(1))
+          }
         }
       }
-    }
 
-    return { before: beforeLines.join("\n"), after: afterLines.join("\n"), patch: diff.patch }
+      return { before: beforeLines.join("\n"), after: afterLines.join("\n"), patch: diff.patch }
+    } catch {
+      return { before: "", after: "", patch: diff.patch }
+    }
   }
   return {
     before: "before" in diff && typeof diff.before === "string" ? diff.before : "",