number of fields in a row has to be based on the header

[mykhaylo-]

To reproduce

Have a csv file with header row with 3 columns and two data rows, first data row with two columns, second - with three. Like this:

First name	Last name	Citizenship
John	Bobkins
Michael	Pepkins	US

While invoking 'readAllWithHeaderAsSequence' on this file, the CSVFieldNumDifferentException is thrown saying that two colums are expected but three are found. It happens because 'fieldsNum' variable in the CsvFileReader.kt is initialized based on the first data row, while it has to be initialized based on the header row.

Expected behavior
The following code has to return two rows:

csvReader().open(filePath) {
                readAllWithHeaderAsSequence().forEach {

. . . 
}

Environment

• kotlin-csv version 0.11.1
• java version - java8
• OS: Windows 10

[doyaaaaaken]

@mykhaylo-
Thank you for reporting!!
I'll investigate this on weekend, thanks.

[mykhaylo-]

@doyaaaaaken thank you.
For your convenience here is the problematic place: https:/doyaaaaaken/kotlin-csv/blob/f4637eb89ed6c1d0d18b23de2405e41294a4c6a9/src/jvmMain/kotlin/com/github/doyaaaaaken/kotlincsv/client/CsvFileReader.kt#L46
Initially "fieldsNum" variable is null and while going over the first data row it is getting initialized with number of fields of this row. Normally when first data row has all the columns set there is no issue and parser works well, but when the first row doesn't have the last column(-s) set, "fieldsNum" is initialized incorrectly. I think the fix here has to be to initialize "fieldsNum" with header row number of fields ( in case "readAllWithHeaderAsSequence" is invoked and header row is present).
Please see my PR with proposed fix: #83

[doyaaaaaken]

@mykhaylo-
Fixed at v0.15.2, thanks for your contribution!! 🙇