Improve with-env robustness (#12523)

# Description
Work for #7149

- **Error `with-env` given uneven count in list form**
- **Fix `with-env` `CantConvert` to record**
- **Error `with-env` when given protected env vars**
- **Deprecate list/table input of vars to `with-env`**
- **Remove examples for deprecated input**

# User-Facing Changes

## Deprecation of the following forms

```
> with-env [MYENV "my env value"] { $env.MYENV }
my env value

> with-env [X Y W Z] { $env.X }
Y

> with-env [[X W]; [Y Z]] { $env.W }
Z
```

## recommended standardized form

```
# Set by key-value record
> with-env {X: "Y", W: "Z"} { [$env.X $env.W] }
╭───┬───╮
│ 0 │ Y │
│ 1 │ Z │
╰───┴───╯
```

## (Side effect) Repeated definitions in an env shorthand are now
disallowed

```
> FOO=bar FOO=baz $env
Error: nu:🐚:column_defined_twice

  × Record field or table column used twice: FOO
   ╭─[entry #1:1:1]
 1 │ FOO=bar FOO=baz $env
   · ─┬─     ─┬─
   ·  │       ╰── field redefined here
   ·  ╰── field first defined here
   ╰────
```

crates/nu-command/src/env/with_env.rs

@@ -41,31 +41,14 @@ impl Command for WithEnv {
     }
 
     fn examples(&self) -> Vec<Example> {
-        vec![
-            Example {
-                description: "Set the MYENV environment variable",
-                example: r#"with-env [MYENV "my env value"] { $env.MYENV }"#,
-                result: Some(Value::test_string("my env value")),
-            },
-            Example {
-                description: "Set by primitive value list",
-                example: r#"with-env [X Y W Z] { $env.X }"#,
-                result: Some(Value::test_string("Y")),
-            },
-            Example {
-                description: "Set by single row table",
-                example: r#"with-env [[X W]; [Y Z]] { $env.W }"#,
-                result: Some(Value::test_string("Z")),
-            },
-            Example {
-                description: "Set by key-value record",
-                example: r#"with-env {X: "Y", W: "Z"} { [$env.X $env.W] }"#,
-                result: Some(Value::list(
-                    vec![Value::test_string("Y"), Value::test_string("Z")],
-                    Span::test_data(),
-                )),
-            },
-        ]
+        vec![Example {
+            description: "Set by key-value record",
+            example: r#"with-env {X: "Y", W: "Z"} { [$env.X $env.W] }"#,
+            result: Some(Value::list(
+                vec![Value::test_string("Y"), Value::test_string("Z")],
+                Span::test_data(),
+            )),
+        }]
     }
 }
 
@@ -85,6 +68,16 @@ fn with_env(
 
     match &variable {
         Value::List { vals: table, .. } => {
+            nu_protocol::report_error_new(
+                engine_state,
+                &ShellError::GenericError {
+                    error: "Deprecated argument type".into(),
+                    msg: "providing the variables to `with-env` as a list or single row table has been deprecated".into(),
+                    span: Some(variable.span()),
+                    help: Some("use the record form instead".into()),
+                    inner: vec![],
+                },
+            );
             if table.len() == 1 {
                 // single row([[X W]; [Y Z]])
                 match &table[0] {
@@ -95,7 +88,7 @@ fn with_env(
                     }
                     x => {
                         return Err(ShellError::CantConvert {
-                            to_type: "string list or single row".into(),
+                            to_type: "record".into(),
                             from_type: x.get_type().to_string(),
                             span: call
                                 .positional_nth(1)
@@ -111,7 +104,13 @@ fn with_env(
                     if row.len() == 2 {
                         env.insert(row[0].coerce_string()?, row[1].clone());
                     }
-                    // TODO: else error?
+                    if row.len() == 1 {
+                        return Err(ShellError::IncorrectValue {
+                            msg: format!("Missing value for $env.{}", row[0].coerce_string()?),
+                            val_span: row[0].span(),
+                            call_span: call.head,
+                        });
+                    }
                 }
             }
         }
@@ -123,7 +122,7 @@ fn with_env(
         }
         x => {
             return Err(ShellError::CantConvert {
-                to_type: "string list or single row".into(),
+                to_type: "record".into(),
                 from_type: x.get_type().to_string(),
                 span: call
                     .positional_nth(1)
@@ -134,6 +133,16 @@ fn with_env(
         }
     };
 
+    // TODO: factor list of prohibited env vars into common place
+    for prohibited in ["PWD", "FILE_PWD", "CURRENT_FILE"] {
+        if env.contains_key(prohibited) {
+            return Err(ShellError::AutomaticEnvVarSetManually {
+                envvar_name: prohibited.into(),
+                span: call.head,
+            });
+        }
+    }
+
     for (k, v) in env {
         stack.add_env_var(k, v);
     }

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

@@ -63,7 +63,7 @@ fn let_pipeline_redirects_externals() {
 #[test]
 fn let_err_pipeline_redirects_externals() {
     let actual = nu!(
-        r#"let x = with-env [FOO "foo"] {nu --testbin echo_env_stderr FOO e>| str length}; $x"#
+        r#"let x = with-env { FOO: "foo" } {nu --testbin echo_env_stderr FOO e>| str length}; $x"#
     );
     assert_eq!(actual.out, "3");
 }
@@ -71,7 +71,7 @@ fn let_err_pipeline_redirects_externals() {
 #[test]
 fn let_outerr_pipeline_redirects_externals() {
     let actual = nu!(
-        r#"let x = with-env [FOO "foo"] {nu --testbin echo_env_stderr FOO o+e>| str length}; $x"#
+        r#"let x = with-env { FOO: "foo" } {nu --testbin echo_env_stderr FOO o+e>| str length}; $x"#
     );
     assert_eq!(actual.out, "3");
 }

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

@@ -90,7 +90,7 @@ fn folding_with_tables() {
         "
         echo [10 20 30 40]
         | reduce --fold [] { |it, acc|
-            with-env [value $it] {
+            with-env { value: $it } {
               echo $acc | append (10 * ($env.value | into int))
             }
           }

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

@@ -2,7 +2,7 @@ use nu_test_support::nu;
 
 #[test]
 fn with_env_extends_environment() {
-    let actual = nu!("with-env [FOO BARRRR] {echo $env} | get FOO");
+    let actual = nu!("with-env { FOO: BARRRR } {echo $env} | get FOO");
 
     assert_eq!(actual.out, "BARRRR");
 }
@@ -32,7 +32,7 @@ fn with_env_shorthand_trims_quotes() {
 fn with_env_and_shorthand_same_result() {
     let actual_shorthand = nu!("FOO='BARRRR' echo $env | get FOO");
 
-    let actual_normal = nu!("with-env [FOO BARRRR] {echo $env} | get FOO");
+    let actual_normal = nu!("with-env { FOO: BARRRR } {echo $env} | get FOO");
 
     assert_eq!(actual_shorthand.out, actual_normal.out);
 }
@@ -50,7 +50,7 @@ fn with_env_hides_variables_in_parent_scope() {
     let actual = nu!(r#"
         $env.FOO = "1"
         print $env.FOO
-        with-env [FOO null] {
+        with-env { FOO: null } {
             echo $env.FOO
         }
         print $env.FOO

crates/nu-parser/src/parser.rs

@@ -5164,9 +5164,8 @@ pub fn parse_expression(working_set: &mut StateWorkingSet, spans: &[Span]) -> Ex
         }
     };
 
-    let with_env = working_set.find_decl(b"with-env");
-
     if !shorthand.is_empty() {
+        let with_env = working_set.find_decl(b"with-env");
         if let Some(decl_id) = with_env {
             let mut block = Block::default();
             let ty = output.ty.clone();
@@ -5176,13 +5175,12 @@ pub fn parse_expression(working_set: &mut StateWorkingSet, spans: &[Span]) -> Ex
 
             let mut env_vars = vec![];
             for sh in shorthand {
-                env_vars.push(sh.0);
-                env_vars.push(sh.1);
+                env_vars.push(RecordItem::Pair(sh.0, sh.1));
             }
 
             let arguments = vec![
                 Argument::Positional(Expression {
-                    expr: Expr::List(env_vars),
+                    expr: Expr::Record(env_vars),
                     span: span(&spans[..pos]),
                     ty: Type::Any,
                     custom_completion: None,

crates/nu-std/std/mod.nu

@@ -22,7 +22,7 @@ use dt.nu [datetime-diff, pretty-print-duration]
 # # Example
 # - adding some dummy paths to an empty PATH
 # ```nushell
-# >_ with-env [PATH []] {
+# >_ with-env { PATH: [] } {
 #     std path add "foo"
 #     std path add "bar" "baz"
 #     std path add "fooo" --append

crates/nu-std/tests/test_std.nu

@@ -6,7 +6,7 @@ def path_add [] {
 
     let path_name = if "PATH" in $env { "PATH" } else { "Path" }
 
-    with-env [$path_name []] {
+    with-env {$path_name: []} {
         def get_path [] { $env | get $path_name }
 
         assert equal (get_path) []

src/tests/test_env.rs

@@ -1,4 +1,4 @@
-use crate::tests::{run_test, TestResult};
+use crate::tests::{fail_test, run_test, TestResult};
 
 #[test]
 fn shorthand_env_1() -> TestResult {
@@ -7,7 +7,7 @@ fn shorthand_env_1() -> TestResult {
 
 #[test]
 fn shorthand_env_2() -> TestResult {
-    run_test(r#"FOO=BAZ FOO=MOO $env.FOO"#, "MOO")
+    fail_test(r#"FOO=BAZ FOO=MOO $env.FOO"#, "defined_twice")
 }
 
 #[test]

tests/shell/environment/env.rs

@@ -121,7 +121,7 @@ fn load_env_pwd_env_var_fails() {
 #[test]
 fn passes_with_env_env_var_to_external_process() {
     let actual = nu!("
-        with-env [FOO foo] {nu --testbin echo_env FOO}
+        with-env { FOO: foo } {nu --testbin echo_env FOO}
         ");
     assert_eq!(actual.out, "foo");
 }

tests/shell/pipeline/commands/external.rs

@@ -133,26 +133,27 @@ fn command_not_found_error_shows_not_found_1() {
 #[test]
 fn command_substitution_wont_output_extra_newline() {
     let actual = nu!(r#"
-        with-env [FOO "bar"] { echo $"prefix (nu --testbin echo_env FOO) suffix" }
+        with-env { FOO: "bar" } { echo $"prefix (nu --testbin echo_env FOO) suffix" }
         "#);
     assert_eq!(actual.out, "prefix bar suffix");
 
     let actual = nu!(r#"
-        with-env [FOO "bar"] { (nu --testbin echo_env FOO) }
+        with-env { FOO: "bar" } { (nu --testbin echo_env FOO) }
         "#);
     assert_eq!(actual.out, "bar");
 }
 
 #[test]
 fn basic_err_pipe_works() {
-    let actual = nu!(r#"with-env [FOO "bar"] { nu --testbin echo_env_stderr FOO e>| str length }"#);
+    let actual =
+        nu!(r#"with-env { FOO: "bar" } { nu --testbin echo_env_stderr FOO e>| str length }"#);
     assert_eq!(actual.out, "3");
 }
 
 #[test]
 fn basic_outerr_pipe_works() {
     let actual = nu!(
-        r#"with-env [FOO "bar"] { nu --testbin echo_env_mixed out-err FOO FOO o+e>| str length }"#
+        r#"with-env { FOO: "bar" } { nu --testbin echo_env_mixed out-err FOO FOO o+e>| str length }"#
     );
     assert_eq!(actual.out, "7");
 }
@@ -160,7 +161,7 @@ fn basic_outerr_pipe_works() {
 #[test]
 fn err_pipe_with_failed_external_works() {
     let actual =
-        nu!(r#"with-env [FOO "bar"] { nu --testbin echo_env_stderr_fail FOO e>| str length }"#);
+        nu!(r#"with-env { FOO: "bar" } { nu --testbin echo_env_stderr_fail FOO e>| str length }"#);
     assert_eq!(actual.out, "3");
 }