fix(extmarks): don't leak memory on error (#22507)

src/nvim/api/extmark.c

@@ -809,8 +809,7 @@ Integer nvim_buf_set_extmark(Buffer buffer, Integer ns_id, Integer line, Integer
   return (Integer)id;
 
 error:
-  clear_virttext(&decor.virt_text);
+  decor_clear(&decor);
-  xfree(decor.sign_text);
   return 0;
 }
 

src/nvim/decoration.c

@@ -112,15 +112,20 @@ void decor_remove(buf_T *buf, int row, int row2, Decoration *decor)
   decor_free(decor);
 }
 
+void decor_clear(Decoration *decor)
+{
+  clear_virttext(&decor->virt_text);
+  for (size_t i = 0; i < kv_size(decor->virt_lines); i++) {
+    clear_virttext(&kv_A(decor->virt_lines, i).line);
+  }
+  kv_destroy(decor->virt_lines);
+  xfree(decor->sign_text);
+}
+
 void decor_free(Decoration *decor)
 {
   if (decor) {
-    clear_virttext(&decor->virt_text);
+    decor_clear(decor);
-    for (size_t i = 0; i < kv_size(decor->virt_lines); i++) {
-      clear_virttext(&kv_A(decor->virt_lines, i).line);
-    }
-    kv_destroy(decor->virt_lines);
-    xfree(decor->sign_text);
     xfree(decor);
   }
 }

test/functional/api/extmark_spec.lua

@@ -107,6 +107,13 @@ describe('API/extmarks', function()
     eq("Invalid 'id': expected positive Integer", pcall_err(set_extmark, ns, {}, 0, 0, { end_col = 1, end_row = 1 }))
     eq("Invalid mark position: expected 2 Integer items", pcall_err(get_extmarks, ns, {}, {-1, -1}))
     eq("Invalid mark position: expected mark id Integer or 2-item Array", pcall_err(get_extmarks, ns, true, {-1, -1}))
+    -- No memory leak with virt_text, virt_lines, sign_text
+    eq("right_gravity is not a boolean", pcall_err(set_extmark, ns, marks[2], 0, 0, {
+      virt_text = {{'foo', 'Normal'}},
+      virt_lines = {{{'bar', 'Normal'}}},
+      sign_text = 'a',
+      right_gravity = 'baz',
+    }))
   end)
 
   it("can end extranges past final newline using end_col = 0", function()