default to $nothing if cellpath not found (#6535)

* default to  if cellpath not found

* fmt

* add test

* fix test

* fix clippy

* move behaviour behind `-i` flag

* prevent any possibility of an unspanned error

* ignore all errors

* seperate testes

* fmt

crates/nu-command/src/filters/get.rs

@@ -28,7 +28,7 @@ impl Command for Get {
             .rest("rest", SyntaxShape::CellPath, "additional cell paths")
             .switch(
                 "ignore-errors",
-                "return nothing if path can't be found",
+                "when there are empty cells, instead of erroring out, replace them with nothing",
                 Some('i'),
             )
             .switch(

crates/nu-command/src/filters/select.rs

@@ -17,6 +17,11 @@ impl Command for Select {
     // FIXME: also add support for --skip
     fn signature(&self) -> Signature {
         Signature::build("select")
+            .switch(
+                "ignore-errors",
+                "when a column has empty cells, instead of erroring out, replace them with nothing",
+                Some('i'),
+            )
             .rest(
                 "rest",
                 SyntaxShape::CellPath,
@@ -42,8 +47,9 @@ impl Command for Select {
     ) -> Result<nu_protocol::PipelineData, nu_protocol::ShellError> {
         let columns: Vec<CellPath> = call.rest(engine_state, stack, 0)?;
         let span = call.head;
+        let ignore_empty = call.has_flag("ignore-errors");
 
-        select(engine_state, span, columns, input)
+        select(engine_state, span, columns, input, ignore_empty)
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -67,6 +73,7 @@ fn select(
     span: Span,
     columns: Vec<CellPath>,
     input: PipelineData,
+    ignore_empty: bool,
 ) -> Result<PipelineData, ShellError> {
     let mut rows = vec![];
 
@@ -121,6 +128,7 @@ fn select(
             ..,
         ) => {
             let mut output = vec![];
+            let mut columns_with_value = Vec::new();
 
             for input_val in input_vals {
                 if !columns.is_empty() {
@@ -128,10 +136,25 @@ fn select(
                     let mut vals = vec![];
                     for path in &columns {
                         //FIXME: improve implementation to not clone
-                        let fetcher = input_val.clone().follow_cell_path(&path.members, false)?;
+                        if ignore_empty {
+                            let fetcher = input_val.clone().follow_cell_path(&path.members, false);
 
-                        cols.push(path.into_string().replace('.', "_"));
+                            cols.push(path.into_string().replace('.', "_"));
-                        vals.push(fetcher);
+                            if let Ok(fetcher) = fetcher {
+                                vals.push(fetcher);
+                                if !columns_with_value.contains(&path) {
+                                    columns_with_value.push(path);
+                                }
+                            } else {
+                                vals.push(Value::nothing(span));
+                            }
+                        } else {
+                            let fetcher =
+                                input_val.clone().follow_cell_path(&path.members, false)?;
+
+                            cols.push(path.into_string().replace('.', "_"));
+                            vals.push(fetcher);
+                        }
                     }
 
                     output.push(Value::Record { cols, vals, span })

crates/nu-command/tests/commands/select.rs

@@ -159,3 +159,27 @@ fn selects_many_rows() {
         assert_eq!(actual.out, "2");
     });
 }
+
+#[test]
+fn select_ignores_errors_succesfully1() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        [{a: 1, b: 2} {a: 3, b: 5} {a: 3}] | select -i b
+            "#
+    ));
+
+    assert!(actual.err.is_empty());
+}
+
+#[test]
+fn select_ignores_errors_succesfully2() {
+    let actual = nu!(
+        cwd: ".", pipeline(
+        r#"
+        [{a: 1} {a: 2} {a: 3}] | select -i b
+            "#
+    ));
+
+    assert!(actual.err.is_empty());
+}