nushell/crates/nu-command
Hudson Clark cb754befe9
fix: Ensure consistent vals and cols when parsing with --flexible (#10814)
# Description
`from tsv` and `from csv` both support a `--flexible` flag. This flag
can be used to "allow the number of fields in records to be variable".

Previously, a record's invariant that `rec.cols.len() == rec.vals.len()`
could be broken during parsing. This can cause runtime errors as in
#10693. Other commands, like `select` were also affected.

The inconsistencies are somewhat hard to see, as most nushell code
assumes an equal number of columns and values.

# Before

### Fewer values than columns
```nushell
> let record = (echo "one,two\n1" | from csv --flexible | first)
# There are two columns
> $record | columns | to nuon
[one, two]
# But only one value
> $record | values | to nuon
[1]
# And printing the record doesn't show the second column!
> $record | to nuon
{one: 1}
```

### More values than columns
```nushell
> let record = (echo "one,two\n1,2,3" | from csv --flexible | first)
# There are two columns
> $record | columns | to nuon
[one, two]
# But three values
> $record | values | to nuon
[1, 2, 3]
# And printing the record doesn't show the third value!
> $record | to nuon
{one: 1, two: 2}
```
# After

### Fewer values than columns
```nushell
> let record = (echo "one,two\n1" | from csv --flexible | first)
# There are two columns
> $record | columns | to nuon
[one, two]
# And a matching number of values
> $record | values | to nuon
[1, null]
# And printing the record works as expected
> $record | to nuon
{one: 1, two: null}
```

### More values than columns
```nushell
> let record = (echo "one,two\n1,2,3" | from csv --flexible | first)
# There are two columns
> $record | columns | to nuon
[one, two]
# And a matching number of values
> $record | values | to nuon
[1, 2]
# And printing the record works as expected
> $record | to nuon
{one: 1, two: 2}
```

# User-Facing Changes
Using the `--flexible` flag with `from csv` and `from tsv` will not
result in corrupted record state.

# Tests + Formatting
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# After Submitting
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2023-10-24 15:54:26 -05:00
..
src fix: Ensure consistent vals and cols when parsing with --flexible (#10814) 2023-10-24 15:54:26 -05:00
tests fix: Ensure consistent vals and cols when parsing with --flexible (#10814) 2023-10-24 15:54:26 -05:00
Cargo.toml Revert "Bump regex from 1.9.6 to 1.10.2" (#10818) 2023-10-23 09:11:32 -05:00
LICENSE Fix rest of license year ranges (#8727) 2023-04-04 09:03:29 +12:00