core: import: auto pid

packages/hydrooj/package.json

@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "3.10.2",
+    "version": "3.10.3",
     "bin": "bin/hydrooj.js",
     "main": "src/loader",
     "module": "src/loader",

packages/hydrooj/src/handler/import.ts

@@ -51,8 +51,11 @@ class ProblemImportHydroHandler extends Handler {
                 if (!files.includes('problem.yaml')) continue;
                 const content = fs.readFileSync(path.join(tmpdir, i, 'problem.yaml'), 'utf-8');
                 const pdoc: ProblemDoc = yaml.load(content) as any;
-                const current = await problem.get(domainId, pdoc.pid);
-                const pid = current ? undefined : pdoc.pid;
+                let pid = pdoc?.pid;
+                if (pid) {
+                    const current = await problem.get(domainId, pid);
+                    if (current) pid = undefined;
+                }
                 const overrideContent = findOverrideContent(path.join(tmpdir, i));
                 const docId = await problem.add(
                     domainId, pid, pdoc.title, overrideContent || pdoc.content,