Infringed constraint on array values causes a type-error

[pierredittgen]

Overview

I'm really excited to use the new feature to constraint array item values (see #627) but I face a problem with errors raised in the validation report.

Given array_sample.csv file:

field1
"[""a""]"
"[""a"",""b""]"
"[""a"",""b"",""c""]"
"[""c""]"

I wrote a first simple schema (array_schema.json file) to insure that field1 contains array values:

{
  "$schema": "https://specs.frictionlessdata.io/schemas/table-schema.json",
  "fields": [
    {
      "name": "field1",
      "type": "array"
    }
  ]
}

I can check that my CSV file is ok:

> frictionless validate --schema array_schema.json array_sample.csv
# -----
# valid: array_sample.csv
# -----

Now, I want to go further and check that array items are only "a" or "b". I extend my schema using arrayItem property (array_with_contraints_schema.json file):

{
  "$schema": "https://specs.frictionlessdata.io/schemas/table-schema.json",
  "fields": [
    {
      "name": "field1",
      "type": "array",
      "arrayItem": { "constraints": { "enum": ["a", "b"] } }
    }
  ]
}

Re-run validate:
```bash
> frictionless validate --schema array_with_contraints_schema.json array_sample.csv 
# -------
# invalid: array_sample.csv
# -------

===  =====  ==========  =============================================================================================================
row  field  code        message                                                                                                      
===  =====  ==========  =============================================================================================================
  4      1  type-error  Type error in the cell "["a","b","c"]" in row "4" and field "field1" at position "1": type is "array/default"
  5      1  type-error  Type error in the cell "["c"]" in row "5" and field "field1" at position "1": type is "array/default"        
===  =====  ==========  =============================================================================================================

I don't understand why I get type-error errors. IMO these errors are not relative to type infrigement. Validate only on type (with array_schema.json) reveals no errors.

Would it be possible to get constraint-error errors instead with a clearer message?

Thx

---

Please preserve this line to notify @roll (lead of this repository)

[roll]

Thanks! I'll handle it

[roll]

Could you please test it with frictionless@4.2

[pierredittgen]

frictionless validate --schema array_with_contraints_schema.json array_sample.csv
# -------
# invalid: array_sample.csv
# -------

===  =====  ================  =================================================================================================================================================================
row  field  code              message                                                                                                                                                          
===  =====  ================  =================================================================================================================================================================
  4      1  constraint-error  The cell "["a","b","c"]" in row at position "4" and field "field1" at position "1" does not conform to a constraint: array item constraint "enum" is "['a', 'b']"
  5      1  constraint-error  The cell "["c"]" in row at position "5" and field "field1" at position "1" does not conform to a constraint: array item constraint "enum" is "['a', 'b']"        
===  =====  ================  =================================================================================================================================================================

Much, much better!

Thanks @roll!