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[SPARK-15264][SPARK-15274][SQL] CSV Reader Error on Blank Column Names #13041

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[SPARK-15264][SPARK-15274][SQL] CSV Reader Error on Blank Column Names #13041

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17b3c58
fix SPARK-15264, add test cases
May 11, 2016
85d0843
Rename test case
bllchmbrs May 11, 2016
0ed0b4c
Fix according to @andrewor14 comments, rename C0 to _c0, fix null checks
May 11, 2016
e380f32
Merge branch 'master' of github.com:anabranch/spark
May 11, 2016
d665bea
fix tests
May 11, 2016
d983718
fix python test failure
May 11, 2016
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4 changes: 3 additions & 1 deletion sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/DefaultSource.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,9 @@ class DefaultSource extends FileFormat with DataSourceRegister {
val firstRow = new LineCsvReader(csvOptions).parseLine(firstLine)

val header = if (csvOptions.headerFlag) {
firstRow
firstRow.zipWithIndex.map { case (value, index) =>
if (value == "" || value == null) s"C$index" else value
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@HyukjinKwon HyukjinKwon May 11, 2016

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I see Spark allows a empty string as a field. So, I wonder if we should rename this with the index and prefix, C. Also, I think "" will throw an NPE whereas empty string without quotes will produce a correct field because the default of nullValue is "".

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@bllchmbrs bllchmbrs May 11, 2016

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This code does rename it with the index and prefix, C.

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@HyukjinKwon HyukjinKwon May 11, 2016 •
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I mean if one of values in the header is a empty string then, I think the field name should be a empty string since apparently it works with fields named empty strings. I tested this by manually giving a schema.

Also, If the header is used for schema, then I think the names should be as they are. We don't really change field names specified in ORC, Parquet or JSON.

}
} else {
firstRow.zipWithIndex.map { case (value, index) => s"C$index" }
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@andrewor14 andrewor14 May 11, 2016

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I talked to @marmbrus offline. Elsewhere we use _c0 instead of C0, so we should make that consistent. You're gonna have to change the name both here and in L65.

}
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3 changes: 3 additions & 0 deletions sql/core/src/test/resources/cars-blank-column-name.csv
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@@ -0,0 +1,3 @@
"",,make,customer,comment
2012,"Tesla","S","bill","blank"
2013,"Tesla","S","c","something"
12 changes: 12 additions & 0 deletions sql/core/src/test/scala/org/apache/spark/sql/execution/datasources/csv/CSVSuite.scala
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Expand Up @@ -38,6 +38,7 @@ class CSVSuite extends QueryTest with SharedSQLContext with SQLTestUtils {
private val carsAltFile = "cars-alternative.csv"
private val carsUnbalancedQuotesFile = "cars-unbalanced-quotes.csv"
private val carsNullFile = "cars-null.csv"
private val carsBlankColName = "cars-blank-column-name.csv"
private val emptyFile = "empty.csv"
private val commentsFile = "comments.csv"
private val disableCommentsFile = "disable_comments.csv"
Expand Down Expand Up @@ -224,6 +225,17 @@ class CSVSuite extends QueryTest with SharedSQLContext with SQLTestUtils {
assert(cars.select("year").collect().size === 2)
}

test("test for blank column names on read and select columns") {
val cars = spark.read
.format("csv")
.options(Map("header" -> "true", "inferSchema" -> "true"))
.load(testFile(carsBlankColName))

assert(cars.select("customer").collect().size == 2)
assert(cars.select("C0").collect().size == 2)
assert(cars.select("C1").collect().size == 2)
}

test("test for FAILFAST parsing mode") {
val exception = intercept[SparkException]{
spark.read
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