Make errors emit first

TODO.md

@@ -25,11 +25,11 @@
 - [x] Modules and imports
 - [x] Exports
 - [x] Source
+- [x] Error shortcircuit (stopping on first error). Revised: errors emit first, but can be seen by commands.
 - [ ] Input/output types
 - [ ] Support for `$in`
 - [ ] Value serialization
 - [ ] Handling rows with missing columns during a cell path
-- [ ] Error shortcircuit (stopping on first error)
 - [ ] ctrl-c support
 - [ ] operator overflow
 - [ ] finish operator type-checking

crates/nu-command/src/viewers/table.rs

@@ -1,6 +1,6 @@
 use nu_protocol::ast::{Call, PathMember};
 use nu_protocol::engine::{Command, EvaluationContext};
-use nu_protocol::{Signature, Span, Value};
+use nu_protocol::{ShellError, Signature, Span, Value};
 use nu_table::StyledString;
 use std::collections::HashMap;
 use terminal_size::{Height, Width};
@@ -35,7 +35,7 @@ impl Command for Table {
 
         match input {
             Value::List { vals, .. } => {
-                let table = convert_to_table(vals);
+                let table = convert_to_table(vals)?;
 
                 if let Some(table) = table {
                     let result = nu_table::draw_table(&table, term_width, &HashMap::new());
@@ -49,7 +49,7 @@ impl Command for Table {
                 }
             }
             Value::Stream { stream, .. } => {
-                let table = convert_to_table(stream);
+                let table = convert_to_table(stream)?;
 
                 if let Some(table) = table {
                     let result = nu_table::draw_table(&table, term_width, &HashMap::new());
@@ -96,7 +96,9 @@ impl Command for Table {
     }
 }
 
-fn convert_to_table(iter: impl IntoIterator<Item = Value>) -> Option<nu_table::Table> {
+fn convert_to_table(
+    iter: impl IntoIterator<Item = Value>,
+) -> Result<Option<nu_table::Table>, ShellError> {
     let mut iter = iter.into_iter().peekable();
 
     if let Some(first) = iter.peek() {
@@ -109,6 +111,9 @@ fn convert_to_table(iter: impl IntoIterator<Item = Value>) -> Option<nu_table::T
         let mut data = vec![];
 
         for (row_num, item) in iter.enumerate() {
+            if let Value::Error { error } = item {
+                return Err(error);
+            }
             let mut row = vec![row_num.to_string()];
 
             if headers.is_empty() {
@@ -135,7 +140,7 @@ fn convert_to_table(iter: impl IntoIterator<Item = Value>) -> Option<nu_table::T
             data.push(row);
         }
 
-        Some(nu_table::Table {
+        Ok(Some(nu_table::Table {
             headers: headers
                 .into_iter()
                 .map(|x| StyledString {
@@ -165,8 +170,8 @@ fn convert_to_table(iter: impl IntoIterator<Item = Value>) -> Option<nu_table::T
                 })
                 .collect(),
             theme: nu_table::Theme::rounded(),
-        })
+        }))
     } else {
-        None
+        Ok(None)
     }
 }

src/main.rs

@@ -148,7 +148,14 @@ fn main() -> Result<()> {
                     };
 
                     match eval_block(&state, &block, Value::nothing()) {
-                        Ok(value) => print_value(value, &state)?,
+                        Ok(value) => {
+                            if let Err(err) = print_value(value, &state) {
+                                let engine_state = engine_state.borrow();
+                                let working_set = StateWorkingSet::new(&*engine_state);
+
+                                report_error(&working_set, &err);
+                            }
+                        }
                         Err(err) => {
                             let engine_state = engine_state.borrow();
                             let working_set = StateWorkingSet::new(&*engine_state);