Report an error if schema isn't loaded

[ldodds]

If a user supplies a schema and we fail to load it, then the application should report an error so its clear that the schema hasn't been applied.

Currently it falls back to not applying any schema validation which is misleading.

As a first step, reporting a basic error would be an immediate improvement.

Reporting why the schema is invalid would also be useful, although there are a range of possible errors:

• invalid JSON
• invalid regex
• invalid values for a constraint specification, e.g. a number or string where true/false is expected
• unknown constraint

The first two are definitely fatal errors. The last two are potentially just warnings. Depends if we want to work on a "best effort" basis.

[bcouston]

I'll be taking invalid regex

[quadrophobiac]

change error message for schema error, currently prints "Sorry, your CSV did not pass validation. Please review the errors and warnings below:"

[quadrophobiac]

lines 26 - 34 of Validation currently always eval false, would be worthwhile working out what condition they were intended to catch

    if io.respond_to?(:tempfile)
      filename = io.original_filename
      csv = File.new(io.tempfile)
      io = File.new(io.tempfile)
    elsif io.class == Hash && !io[:body].nil?
      filename = io[:filename]
      csv_id = io[:csv_id]
      io = StringIO.new(io[:body])
    end

[Floppy]

@quadrophobiac you mean both of these conditions always fail? The first looks like it's intended to handle uploaded files, and the second ... not sure. Will look at the context....

[Floppy]

@quadrophobiac do you mean this section? https://github.com/theodi/csvlint/blob/master/app/models/validation.rb#L19

The line numbers seems different...

[quadrophobiac]

Yes apologies - I was referring to the line numbers on the error-reporting-schema_expanded-test-suite branch

[quadrophobiac]

I've confirmed non triggering by running the tests suite with a byebug in each conditional

[Floppy]

Ah, I looked on the fix-schema branch but not the other - my bad. Looking closer now.

[bcouston]

Started a pull request on invalid regex functionality: Data-Liberation-Front/csvlint.rb#132

[pezholio]

Data-Liberation-Front/csvlint.rb#132 is good to go - so we need to make sure the newly created errors are shown this end