fix: apply_patch move to same path deletes the file

packages/opencode/src/tool/apply_patch.ts

@@ -234,6 +234,13 @@ export const ApplyPatchTool = Tool.define(
 
           case "move":
             if (change.movePath) {
+              // Move to the same path degenerates to an update — otherwise write+remove would delete the file just written.
+              if (change.movePath === change.filePath) {
+                yield* afs.writeWithDirs(change.filePath, Bom.join(change.newContent, change.bom))
+                updates.push({ file: change.filePath, event: "change" })
+                break
+              }
+
               // Create parent directories (recursive: true is safe on existing/root dirs)
 
               yield* afs.writeWithDirs(change.movePath!, Bom.join(change.newContent, change.bom))

packages/opencode/test/tool/apply_patch.test.ts

@@ -298,6 +298,21 @@ describe("tool.apply_patch freeform", () => {
     }),
   )
 
+  it.instance("treats move-to-same-path as an update", () =>
+    Effect.gen(function* () {
+      const test = yield* TestInstance
+      const { ctx } = makeCtx()
+      const target = path.join(test.directory, "same.txt")
+      yield* writeText(target, "old content\n")
+
+      const patchText =
+        "*** Begin Patch\n*** Update File: same.txt\n*** Move to: same.txt\n@@\n-old content\n+new content\n*** End Patch"
+
+      yield* execute({ patchText }, ctx)
+      expect(yield* readText(target)).toBe("new content\n")
+    }),
+  )
+
   it.instance("adds file overwriting existing file", () =>
     Effect.gen(function* () {
       const test = yield* TestInstance