fix counterintuitive behavior of has_n_cols for csv

[d-callan]

basically encountered counterintuitive behavior where has_n_columns assertion in tests for a tool that output csv kept failing saying it only saw 1 column in the file. delimiter apparently defaults to tab for csv ftype. apparently i can explicitly set sep for csv to make this work, which is great, outside the fact i had no idea i needed to. id rather not need to, so this pr represents a proposal to change the delimiter based on ftype.

How to test the changes?

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• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

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[bernt-matthias]

Good idea.

Do you think we should cover other tabular datatypes as well:
https://github.com/galaxyproject/galaxy/blob/dev/lib/galaxy/datatypes/tabular.py. Guess with csv we have at least the most frequent one.

Could you update the docs:

galaxy/lib/galaxy/tool_util/xsd/galaxy.xsd

Line 2600 in 97452de

<xs:element name="has_n_columns">

[nsoranzo]

I'm on the fence on this, I fear that having a default changing with the datatype could be more confusing than helpful. The sep attribute is clearly documented at https://docs.galaxyproject.org/en/master/dev/schema.html#id228

[bernt-matthias]

I'm on the fence on this,

Then a profile version could be an idea.

[d-callan]

Then a profile version could be an idea.

i think i understand this sentence, and i think i like it lol

[d-callan]

fwiw looking through the other tabular data types, they appear at glance to all be tab delimited except csv. so the existing default works except for csv, in which case its highly confusing and feels like a bug.

[d-callan]

ok. well, ive updated the docs i was pointed to. and ive taken a look around and think i see how to make the profile version thing work. so let me know if thats something worth pursuing.

[bernt-matthias]

so let me know if thats something worth pursuing.

IMO Yes.