[GitHub] [spark] ueshin commented on a diff in pull request #36640: [SPARK-39262][PYTHON] Correct the behavior of creating DataFrame from an RDD

[GitBox <gi...@apache.org>]

ueshin commented on code in PR #36640:
URL: https://github.com/apache/spark/pull/36640#discussion_r885944686


##########
python/pyspark/sql/session.py:
##########
@@ -611,8 +611,8 @@ def _inferSchema(
         :class:`pyspark.sql.types.StructType`
         """
         first = rdd.first()
-        if not first:
-            raise ValueError("The first row in RDD is empty, " "can not infer schema")
+        if first is None:

Review Comment:
   If `rdd.first()` uses `if rs:` check, `first` will never be `[]`, `{}`, `0` or `""`, either?
   I guess we should fix `rdd.first()` to properly return the first row, and `if first is None:` check here is vaild according to the error message `"The first row in RDD is empty, can not infer schema"`.



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