From 202dfdaee24b982c7086ba5fa658540736a23dc5 Mon Sep 17 00:00:00 2001
From: Antoine Stevan <44101798+amtoine@users.noreply.github.com>
Date: Wed, 9 Aug 2023 14:12:58 +0200
Subject: [PATCH] fix panic with `lines` on an error (#9967)
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should close https://github.com/nushell/nushell/issues/9965

# Description
this PR implements the `todo!()` left in `lines`.

# User-Facing Changes
### before
```nushell
> open . | lines
thread 'main' panicked at 'not yet implemented', crates/nu-command/src/filters/lines.rs:248:35
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
```

### after
```nushell
> open . | lines
Error: nu::shell::io_error

  × I/O error
  help: Is a directory (os error 21)
```

# Tests + Formatting
- :green_circle: `toolkit fmt`
- :green_circle: `toolkit clippy`
- :black_circle: `toolkit test`
- :black_circle: `toolkit test stdlib`

this PR adds the `lines_on_error` test to make sure this does not happen
again :relieved:

# After Submitting
---
 crates/nu-command/src/filters/lines.rs    | 2 +-
 crates/nu-command/tests/commands/lines.rs | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/crates/nu-command/src/filters/lines.rs b/crates/nu-command/src/filters/lines.rs
index 31fbcf2c2..322d8a879 100644
--- a/crates/nu-command/src/filters/lines.rs
+++ b/crates/nu-command/src/filters/lines.rs
@@ -245,7 +245,7 @@ impl Iterator for RawStreamLinesAdapter {
                                 }
                             }
                         }
-                        Err(_) => todo!(),
+                        Err(err) => return Some(Err(err)),
                     }
                 } else {
                     self.inner_complete = true;
diff --git a/crates/nu-command/tests/commands/lines.rs b/crates/nu-command/tests/commands/lines.rs
index ee8dc5881..2bfebbabf 100644
--- a/crates/nu-command/tests/commands/lines.rs
+++ b/crates/nu-command/tests/commands/lines.rs
@@ -61,3 +61,11 @@ fn lines_mixed_line_endings() {
 
     assert_eq!(actual.out, "3");
 }
+
+#[cfg(not(windows))]
+#[test]
+fn lines_on_error() {
+    let actual = nu!("open . | lines");
+
+    assert!(actual.err.contains("Is a directory"));
+}