Properly evaluate dynamic blocks (nushell#3339)

crates/nu-engine/src/evaluate/block.rs

@@ -137,51 +137,35 @@ fn run_pipeline(
  }
  }
 
- match &call.head.expr {
- Expression::Block(block) => {
+ let block = run_expression_block(&call.head, ctx)?.into_vec();
+
+ if block.len() != 1 {
+ return Err(ShellError::labeled_error(
+ "Dynamic commands must start with a block",
+ "needs to be a block",
+ call.head.span,
+ ));
+ }
+
+ match &block[0].value {
+ UntaggedValue::Block(captured_block) => {
  ctx.scope.enter_scope();
- for (param, value) in block.params.positional.iter().zip(args.iter()) {
+ ctx.scope.add_vars(&captured_block.captured.entries);
+ for (param, value) in captured_block
+ .block
+ .params
+ .positional
+ .iter()
+ .zip(args.iter())
+ {
  ctx.scope.add_var(param.0.name(), value[0].clone());
  }
- let result = run_block(&block, ctx, input);
+ let result = run_block(&captured_block.block, ctx, input);
  ctx.scope.exit_scope();
 
  let result = result?;
  return Ok(result);
  }
- Expression::Variable(v, span) => {
- if let Some(value) = ctx.scope.get_var(v) {
- match &value.value {
- UntaggedValue::Block(captured_block) => {
- ctx.scope.enter_scope();
- ctx.scope.add_vars(&captured_block.captured.entries);
- for (param, value) in captured_block
- .block
- .params
- .positional
- .iter()
- .zip(args.iter())
- {
- ctx.scope.add_var(param.0.name(), value[0].clone());
- }
- let result = run_block(&captured_block.block, ctx, input);
- ctx.scope.exit_scope();
-
- let result = result?;
- return Ok(result);
- }
- _ => {
- return Err(ShellError::labeled_error("Dynamic commands must start with a block (or variable pointing to a block)", "needs to be a block", call.head.span));
- }
- }
- } else {
- return Err(ShellError::labeled_error(
- "Variable not found",
- "variable not found",
- span,
- ));
- }
- }
  _ => {
  return Err(ShellError::labeled_error("Dynamic commands must start with a block (or variable pointing to a block)", "needs to be a block", call.head.span));
  }

tests/shell/pipeline/commands/internal.rs

@@ -391,6 +391,17 @@ fn proper_shadow_set_aliases() {
  assert_eq!(actual.out, "falsetruefalse");
 }
 
+#[test]
+fn run_dynamic_blocks() {
+ let actual = nu!(
+ cwd: ".",
+ r#"
+ let block = { echo "holaaaa" }; $block
+ "#
+ );
+ assert_eq!(actual.out, "holaaaa");
+}
+
 #[cfg(feature = "which")]
 #[test]
 fn argument_invocation_reports_errors() {