[SPARK-19165] UserDefinedFunction should verify call arguments and provide readable exception in case of mismatch

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.6.0, 2.0.0, 2.1.0, 2.2.0
• Fix Version/s: 2.3.0
• Component/s: PySpark, SQL
• Assignee: Hyukjin Kwon
• Reporter: Maciej Szymkiewicz
• Created: 10/Jan/17 21:39
• Updated: 12/Dec/22 18:10
• Resolved: 24/Aug/17 11:29

Description

Invalid arguments to UDF call fail with a bit cryptic Py4J errors:

In [5]: g = udf(lambda x: x)

In [6]: df.select(f([]))

---------------------------------------------------------------------------
Py4JError                                 Traceback (most recent call last)
<ipython-input-10-5fb48a5d66d2> in <module>()
----> 1 df.select(f([]))
....
Py4JError: An error occurred while calling z:org.apache.spark.sql.functions.col. Trace:
py4j.Py4JException: Method col([class java.util.ArrayList]) does not exist
	at py4j.reflection.ReflectionEngine.getMethod(ReflectionEngine.java:318)
	at py4j.reflection.ReflectionEngine.getMethod(ReflectionEngine.java:339)
	at py4j.Gateway.invoke(Gateway.java:274)
	at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
	at py4j.commands.CallCommand.execute(CallCommand.java:79)
	at py4j.GatewayConnection.run(GatewayConnection.java:214)
	at java.lang.Thread.run(Thread.java:745)

It is pretty easy to perform basic input validation:

In [8]: f = udf(lambda x: x)

In [9]: f(1)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)

...
TypeError: All arguments should be Columns or strings representing column names. Got 1 of type <class 'int'>

This can be further extended to check for expected number of arguments or even, with some type of annotations, SQL types.

Issue Links

• links to: [Github] Pull Request #16537 (zero323)
• links to: [Github] Pull Request #19027 (HyukjinKwon)