fix split list when separater is the first element of list (#7355)

# Description

Fixes: #7278

# User-Facing Changes

_(List of all changes that impact the user experience here. This helps
us keep track of breaking changes.)_

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass

# After Submitting

If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.

crates/nu-command/src/strings/split/list.rs

@@ -95,6 +95,31 @@ impl Command for SubCommand {
  span: Span::test_data(),
  }),
  },
+ Example {
+ description: "Split a list of chars into two lists",
+ example: "[a, b, c, d, a, e, f, g] | split list a",
+ result: Some(Value::List {
+ vals: vec![
+ Value::List {
+ vals: vec![
+ Value::test_string("b"),
+ Value::test_string("c"),
+ Value::test_string("d"),
+ ],
+ span: Span::test_data(),
+ },
+ Value::List {
+ vals: vec![
+ Value::test_string("e"),
+ Value::test_string("f"),
+ Value::test_string("g"),
+ ],
+ span: Span::test_data(),
+ },
+ ],
+ span: Span::test_data(),
+ }),
+ },
  ]
  }
 }
@@ -110,12 +135,14 @@ fn split_list(
  let mut returned_list = Vec::new();
  let iter = input.into_interruptible_iter(engine_state.ctrlc.clone());
  for val in iter {
- if val == separator && !temp_list.is_empty() {
- returned_list.push(Value::List {
- vals: temp_list.clone(),
- span: call.head,
- });
- temp_list = Vec::new();
+ if val == separator {
+ if !temp_list.is_empty() {
+ returned_list.push(Value::List {
+ vals: temp_list.clone(),
+ span: call.head,
+ });
+ temp_list = Vec::new();
+ }
  } else {
  temp_list.push(val);
  }