nushell/src/tests/test_table_operations.rs
Reilly Wood 21b84a6d65
Optional members in cell paths: Attempt 2 (#8379)
This is a follow up from https://github.com/nushell/nushell/pull/7540.
Please provide feedback if you have the time!

## Summary

This PR lets you use `?` to indicate that a member in a cell path is
optional and Nushell should return `null` if that member cannot be
accessed.

Unlike the previous PR, `?` is now a _postfix_ modifier for cell path
members. A cell path of `.foo?.bar` means that `foo` is optional and
`bar` is not.

`?` does _not_ suppress all errors; it is intended to help in situations
where data has "holes", i.e. the data types are correct but something is
missing. Type mismatches (like trying to do a string path access on a
date) will still fail.

### Record Examples

```bash

{ foo: 123 }.foo # returns 123

{ foo: 123 }.bar # errors
{ foo: 123 }.bar? # returns null

{ foo: 123 } | get bar # errors
{ foo: 123 } | get bar? # returns null

{ foo: 123 }.bar.baz # errors
{ foo: 123 }.bar?.baz # errors because `baz` is not present on the result from `bar?`
{ foo: 123 }.bar.baz? # errors
{ foo: 123 }.bar?.baz? # returns null
```

### List Examples
```
〉[{foo: 1} {foo: 2} {}].foo
Error: nu:🐚:column_not_found

  × Cannot find column
   ╭─[entry #30:1:1]
 1 │ [{foo: 1} {foo: 2} {}].foo
   ·                    ─┬  ─┬─
   ·                     │   ╰── cannot find column 'foo'
   ·                     ╰── value originates here
   ╰────
〉[{foo: 1} {foo: 2} {}].foo?
╭───┬───╮
│ 0 │ 1 │
│ 1 │ 2 │
│ 2 │   │
╰───┴───╯
〉[{foo: 1} {foo: 2} {}].foo?.2 | describe
nothing

〉[a b c].4? | describe
nothing

〉[{foo: 1} {foo: 2} {}] | where foo? == 1
╭───┬─────╮
│ # │ foo │
├───┼─────┤
│ 0 │   1 │
╰───┴─────╯
```

# Breaking changes

1. Column names with `?` in them now need to be quoted.
2. The `-i`/`--ignore-errors` flag has been removed from `get` and
`select`
1. After this PR, most `get` error handling can be done with `?` and/or
`try`/`catch`.
4. Cell path accesses like this no longer work without a `?`:
```bash
〉[{a:1 b:2} {a:3}].b.0
2
```
We had some clever code that was able to recognize that since we only
want row `0`, it's OK if other rows are missing column `b`. I removed
that because it's tricky to maintain, and now that query needs to be
written like:


```bash
〉[{a:1 b:2} {a:3}].b?.0
2
```

I think the regression is acceptable for now. I plan to do more work in
the future to enable streaming of cell path accesses, and when that
happens I'll be able to make `.b.0` work again.
2023-03-15 20:50:58 -07:00

309 lines
6.4 KiB
Rust

use crate::tests::{fail_test, run_test, TestResult};
#[test]
fn cell_path_subexpr1() -> TestResult {
run_test("([[lang, gems]; [nu, 100]]).lang | get 0", "nu")
}
#[test]
fn cell_path_subexpr2() -> TestResult {
run_test("([[lang, gems]; [nu, 100]]).lang.0", "nu")
}
#[test]
fn cell_path_var1() -> TestResult {
run_test("let x = [[lang, gems]; [nu, 100]]; $x.lang | get 0", "nu")
}
#[test]
fn cell_path_var2() -> TestResult {
run_test("let x = [[lang, gems]; [nu, 100]]; $x.lang.0", "nu")
}
#[test]
fn flatten_simple_list() -> TestResult {
run_test(
"[[N, u, s, h, e, l, l]] | flatten | str join (char nl)",
"N\nu\ns\nh\ne\nl\nl",
)
}
#[test]
fn flatten_get_simple_list() -> TestResult {
run_test("[[N, u, s, h, e, l, l]] | flatten | get 0", "N")
}
#[test]
fn flatten_table_get() -> TestResult {
run_test(
"[[origin, people]; [Ecuador, ([[name, meal]; ['Andres', 'arepa']])]] | flatten --all | get meal.0",
"arepa",
)
}
#[test]
fn flatten_table_column_get_last() -> TestResult {
run_test(
"[[origin, crate, versions]; [World, ([[name]; ['nu-cli']]), ['0.21', '0.22']]] | flatten versions --all | last | get versions",
"0.22",
)
}
#[test]
fn flatten_should_just_flatten_one_level() -> TestResult {
run_test(
"[[origin, crate, versions]; [World, ([[name]; ['nu-cli']]), ['0.21', '0.22']]] | flatten crate | get crate.name.0",
"nu-cli"
)
}
#[test]
fn flatten_nest_table_when_all_provided() -> TestResult {
run_test(
"[[origin, crate, versions]; [World, ([[name]; ['nu-cli']]), ['0.21', '0.22']]] | flatten crate --all | get name.0",
"nu-cli"
)
}
#[test]
fn get_table_columns_1() -> TestResult {
run_test(
"[[name, age, grade]; [paul,21,a]] | columns | first",
"name",
)
}
#[test]
fn get_table_columns_2() -> TestResult {
run_test("[[name, age, grade]; [paul,21,a]] | columns | get 1", "age")
}
#[test]
fn flatten_should_flatten_inner_table() -> TestResult {
run_test(
"[[[name, value]; [abc, 123]]] | flatten --all | get value.0",
"123",
)
}
#[test]
fn command_filter_reject_1() -> TestResult {
run_test(
"[[lang, gems]; [nu, 100]] | reject gems | to json",
r#"[
{
"lang": "nu"
}
]"#,
)
}
#[test]
fn command_filter_reject_2() -> TestResult {
run_test(
"[[lang, gems, grade]; [nu, 100, a]] | reject gems grade | to json",
r#"[
{
"lang": "nu"
}
]"#,
)
}
#[test]
fn command_filter_reject_3() -> TestResult {
run_test(
"[[lang, gems, grade]; [nu, 100, a]] | reject grade gems | to json",
r#"[
{
"lang": "nu"
}
]"#,
)
}
#[test]
#[rustfmt::skip]
fn command_filter_reject_4() -> TestResult {
run_test(
"[[lang, gems, grade]; [nu, 100, a]] | reject gems | to json -r",
r#"[{"lang": "nu","grade": "a"}]"#,
)
}
#[test]
fn command_drop_column_1() -> TestResult {
run_test(
"[[lang, gems, grade]; [nu, 100, a]] | drop column 2 | to json",
r#"[
{
"lang": "nu"
}
]"#,
)
}
#[test]
fn record_1() -> TestResult {
run_test(r#"{'a': 'b'} | get a"#, "b")
}
#[test]
fn record_2() -> TestResult {
run_test(r#"{'b': 'c'}.b"#, "c")
}
#[test]
fn where_on_ranges() -> TestResult {
run_test(r#"1..10 | where $it > 8 | math sum"#, "19")
}
#[test]
fn index_on_list() -> TestResult {
run_test(r#"[1, 2, 3].1"#, "2")
}
#[test]
fn update_cell_path_1() -> TestResult {
run_test(
r#"[[name, size]; [a, 1.1]] | into int size | get size.0"#,
"1",
)
}
#[test]
fn missing_column_errors() -> TestResult {
fail_test(
r#"[ { name: ABC, size: 20 }, { name: HIJ } ].size.1 == null"#,
"cannot find column",
)
}
#[test]
fn missing_optional_column_fills_in_nothing() -> TestResult {
// The empty value will be replaced with $nothing because of the ?
run_test(
r#"[ { name: ABC, size: 20 }, { name: HIJ } ].size?.1 == $nothing"#,
"true",
)
}
#[test]
fn missing_required_row_fails() -> TestResult {
// .3 will fail if there is no 3rd row
fail_test(
r#"[ { name: ABC, size: 20 }, { name: HIJ } ].3"#,
"", // we just care if it errors
)
}
#[test]
fn missing_optional_row_fills_in_nothing() -> TestResult {
// ?.3 will return $nothing if there is no 3rd row
run_test(
r#"[ { name: ABC, size: 20 }, { name: HIJ } ].3? == $nothing"#,
"true",
)
}
#[test]
fn string_cell_path() -> TestResult {
run_test(
r#"let x = "name"; [["name", "score"]; [a, b], [c, d]] | get $x | get 1"#,
"c",
)
}
#[test]
fn split_row() -> TestResult {
run_test(r#""hello world" | split row " " | get 1"#, "world")
}
#[test]
fn split_column() -> TestResult {
run_test(
r#""hello world" | split column " " | get "column1".0"#,
"hello",
)
}
#[test]
fn wrap() -> TestResult {
run_test(r#"([1, 2, 3] | wrap foo).foo.1"#, "2")
}
#[test]
fn get() -> TestResult {
run_test(
r#"[[name, grade]; [Alice, A], [Betty, B]] | get grade.1"#,
"B",
)
}
#[test]
fn select_1() -> TestResult {
run_test(
r#"([[name, age]; [a, 1], [b, 2]]) | select name | get 1 | get name"#,
"b",
)
}
#[test]
fn select_2() -> TestResult {
run_test(
r#"[[name, age]; [a, 1] [b, 2]] | get 1 | select age | get age"#,
"2",
)
}
#[test]
fn update_will_insert() -> TestResult {
run_test(r#"{} | upsert a b | get a"#, "b")
}
#[test]
fn length_for_columns() -> TestResult {
run_test(
r#"[[name,age,grade]; [bill,20,a] [a b c]] | length -c"#,
"3",
)
}
#[test]
fn length_for_rows() -> TestResult {
run_test(r#"[[name,age,grade]; [bill,20,a] [a b c]] | length"#, "2")
}
#[test]
fn length_defaulted_columns() -> TestResult {
run_test(
r#"[[name, age]; [test, 10]] | default 11 age | get 0 | columns | length"#,
"2",
)
}
#[test]
fn nullify_errors() -> TestResult {
run_test("([{a:1} {a:2} {a:3}] | get foo? | length) == 3", "true")?;
run_test(
"([{a:1} {a:2} {a:3}] | get foo? | to nuon) == '[null, null, null]'",
"true",
)
}
#[test]
fn nullify_holes() -> TestResult {
run_test(
"([{a:1} {b:2} {a:3}] | get a? | to nuon) == '[1, null, 3]'",
"true",
)
}
#[test]
fn get_insensitive() -> TestResult {
run_test(
r#"[[name, age]; [a, 1] [b, 2]] | get NAmE | select 0 | get 0"#,
"a",
)
}