b56f79cc35
## What changes were proposed in this pull request?
This PR proposes `StructType.fieldNames` that returns a copy of a field name list rather than a (undocumented) `StructType.names`.
There are two points here:
- API consistency with Scala/Java
- Provide a safe way to get the field names. Manipulating these might cause unexpected behaviour as below:
```python
from pyspark.sql.types import *
struct = StructType([StructField("f1", StringType(), True)])
names = struct.names
del names[0]
spark.createDataFrame([{"f1": 1}], struct).show()
```
```
...
java.lang.IllegalStateException: Input row doesn't have expected number of values required by the schema. 1 fields are required while 0 values are provided.
at org.apache.spark.sql.execution.python.EvaluatePython$.fromJava(EvaluatePython.scala:138)
at org.apache.spark.sql.SparkSession$$anonfun$6.apply(SparkSession.scala:741)
at org.apache.spark.sql.SparkSession$$anonfun$6.apply(SparkSession.scala:741)
...
```
## How was this patch tested?
Added tests in `python/pyspark/sql/tests.py`.
Author: hyukjinkwon <gurwls223@gmail.com>
Closes #18618 from HyukjinKwon/SPARK-20090.
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|---|---|---|
| .. | ||
| __init__.py | ||
| catalog.py | ||
| column.py | ||
| conf.py | ||
| context.py | ||
| dataframe.py | ||
| functions.py | ||
| group.py | ||
| readwriter.py | ||
| session.py | ||
| streaming.py | ||
| tests.py | ||
| types.py | ||
| utils.py | ||
| window.py | ||