fix(srt): handle undefined/null text in malformed SRT files (#1986)

* fix(cli/srt): filter out undefined/null subtitle entries during push and pull operations

* fix(cli/srt): add warning for skipping undefined/null subtitle entries during push

Author: cherkanovart

.changeset/fix-srt-undefined.md

@@ -0,0 +1,5 @@
+---
+"lingo.dev": patch
+---
+
+fix(srt): filter undefined/null subtitle entries during push

packages/cli/src/cli/loaders/index.spec.ts

@@ -2851,6 +2851,84 @@ World!
 
       expect(data).toEqual({ "2#00:00:01,000-00:00:02,000": "World!" });
     });
+
+    it("should handle undefined text values in payload", async () => {
+      setupFileMocks();
+
+      const input = `
+1
+00:00:00,000 --> 00:00:01,000
+Hello!
+
+2
+00:00:01,000 --> 00:00:02,000
+World!
+
+3
+00:00:02,000 --> 00:00:03,000
+Test!
+  `.trim();
+
+      const payload = {
+        "1#00:00:00,000-00:00:01,000": "¡Hola!",
+        "2#00:00:01,000-00:00:02,000": undefined as any,
+        "3#00:00:02,000-00:00:03,000": "¡Prueba!",
+      };
+
+      const expectedOutput = `1
+00:00:00,000 --> 00:00:01,000
+¡Hola!
+
+3
+00:00:02,000 --> 00:00:03,000
+¡Prueba!`;
+
+      mockFileOperations(input);
+
+      const srtLoader = createBucketLoader("srt", "i18n/[locale].srt", {
+        defaultLocale: "en",
+      });
+      srtLoader.setDefaultLocale("en");
+      await srtLoader.pull("en");
+
+      await srtLoader.push("es", payload);
+
+      expect(fs.writeFile).toHaveBeenCalledWith("i18n/es.srt", expectedOutput, {
+        encoding: "utf-8",
+        flag: "w",
+      });
+    });
+
+    it("should handle malformed SRT entries with undefined text during pull", async () => {
+      setupFileMocks();
+
+      // Simulating malformed SRT that causes parser to return undefined text
+      const malformedInput = `1
+00:00:00,000 --> 00:00:01,000
+Hello!
+
+2
+00:00:01,000 -- 00:00:02,000
+World!
+
+3
+00:00:02,000 --> 00:00:03,000
+Test!`;
+
+      mockFileOperations(malformedInput);
+
+      const srtLoader = createBucketLoader("srt", "i18n/[locale].srt", {
+        defaultLocale: "en",
+      });
+      srtLoader.setDefaultLocale("en");
+      const data = await srtLoader.pull("en");
+
+      // Should only include entries with valid text, skipping malformed entry #2
+      expect(data).toHaveProperty("1#00:00:00,000-00:00:01,000");
+      expect(data).toHaveProperty("3#00:00:02,000-00:00:03,000");
+      // Entry #2 should be filtered out if parser returns undefined text
+      expect(data).not.toHaveProperty("2#00:00:01,000-00:00:02,000");
+    });
   });
 
   describe("xliff bucket loader", () => {

packages/cli/src/cli/loaders/srt.ts

@@ -13,27 +13,39 @@ export default function createSrtLoader(): ILoader<
       const result: Record<string, string> = {};
 
       parsed.forEach((entry) => {
-        const key = `${entry.id}#${entry.startTime}-${entry.endTime}`;
-        result[key] = entry.text;
+        if (entry.text !== undefined && entry.text !== null) {
+          const key = `${entry.id}#${entry.startTime}-${entry.endTime}`;
+          result[key] = entry.text;
+        }
       });
 
       return result;
     },
 
     async push(locale, payload) {
-      const output = Object.entries(payload).map(([key, text]) => {
-        const [id, timeRange] = key.split("#");
-        const [startTime, endTime] = timeRange.split("-");
+      const output = Object.entries(payload)
+        .filter(([key, text]) => {
+          if (text === undefined || text === null) {
+            console.warn(
+              `⚠️  [SRT] Skipping subtitle entry ${key} - text is ${text === undefined ? "undefined" : "null"}`,
+            );
+            return false;
+          }
+          return true;
+        })
+        .map(([key, text]) => {
+          const [id, timeRange] = key.split("#");
+          const [startTime, endTime] = timeRange.split("-");
 
-        return {
-          id: id,
-          startTime: startTime,
-          startSeconds: 0,
-          endTime: endTime,
-          endSeconds: 0,
-          text: text,
-        };
-      });
+          return {
+            id: id,
+            startTime: startTime,
+            startSeconds: 0,
+            endTime: endTime,
+            endSeconds: 0,
+            text: text,
+          };
+        });
 
       const srtContent = parser.toSrt(output).trim().replace(/\r?\n/g, "\n");
       return srtContent;