Error printing changes for watch (#5389)

* Move CliError to nu-protocol

clean up comment

* Enable printing errors instead of just returning them

* Nicer Miette error printing in watch command

crates/nu-cli/src/lib.rs

@@ -1,7 +1,6 @@
 mod commands;
 mod completions;
 mod config_files;
-mod errors;
 mod eval_file;
 mod menus;
 mod nu_highlight;
@@ -17,7 +16,6 @@ mod validation;
 pub use commands::evaluate_commands;
 pub use completions::{FileCompletion, NuCompleter};
 pub use config_files::eval_config_contents;
-pub use errors::CliError;
 pub use eval_file::evaluate_file;
 pub use menus::{DescriptionMenu, NuHelpCompleter};
 pub use nu_highlight::NuHighlight;

crates/nu-cli/src/util.rs

@@ -1,8 +1,8 @@
-use crate::CliError;
 use log::trace;
 use nu_engine::eval_block;
 use nu_parser::{escape_quote_string, lex, parse, unescape_unquote_string, Token, TokenContents};
 use nu_protocol::engine::StateWorkingSet;
+use nu_protocol::CliError;
 use nu_protocol::{
     engine::{EngineState, Stack},
     PipelineData, ShellError, Span, Value,

crates/nu-command/src/filesystem/watch.rs

@@ -6,10 +6,10 @@ use std::time::Duration;
 use notify::{DebouncedEvent, RecommendedWatcher, RecursiveMode, Watcher};
 use nu_engine::{current_dir, eval_block, CallExt};
 use nu_protocol::ast::Call;
-use nu_protocol::engine::{CaptureBlock, Command, EngineState, Stack};
+use nu_protocol::engine::{CaptureBlock, Command, EngineState, Stack, StateWorkingSet};
 use nu_protocol::{
-    Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Spanned, SyntaxShape,
-    Value,
+    format_error, Category, Example, IntoPipelineData, PipelineData, ShellError, Signature,
+    Spanned, SyntaxShape, Value,
 };
 
 // durations chosen mostly arbitrarily
@@ -219,9 +219,8 @@ impl Command for Watch {
                             val.print(engine_state, stack)?;
                         }
                         Err(err) => {
-                            // TODO: this isn't as nice as the Miette errors. Find a way to print those.
-                            // Unfortunately can't just wrap err in PipelineData, PipelineData.print() doesn't work that way
-                            eprintln!("{err:?}");
+                            let working_set = StateWorkingSet::new(engine_state);
+                            eprintln!("{}", format_error(&working_set, &err));
                         }
                     }
                 }

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

@@ -3,10 +3,10 @@ use nu_color_config::{get_color_config, style_primitive};
 use nu_engine::column::get_columns;
 use nu_engine::{env_to_string, CallExt};
 use nu_protocol::ast::{Call, PathMember};
-use nu_protocol::engine::{Command, EngineState, Stack};
+use nu_protocol::engine::{Command, EngineState, Stack, StateWorkingSet};
 use nu_protocol::{
-    Category, Config, DataSource, Example, IntoPipelineData, ListStream, PipelineData,
-    PipelineMetadata, RawStream, ShellError, Signature, Span, SyntaxShape, Value,
+    format_error, Category, Config, DataSource, Example, IntoPipelineData, ListStream,
+    PipelineData, PipelineMetadata, RawStream, ShellError, Signature, Span, SyntaxShape, Value,
 };
 use nu_table::{StyledString, TextStyle, Theme};
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -141,7 +141,14 @@ impl Command for Table {
                 }
                 .into_pipeline_data())
             }
-            PipelineData::Value(Value::Error { error }, ..) => Err(error),
+            PipelineData::Value(Value::Error { error }, ..) => {
+                let working_set = StateWorkingSet::new(engine_state);
+                Ok(Value::String {
+                    val: format_error(&working_set, &error),
+                    span: call.head,
+                }
+                .into_pipeline_data())
+            }
             PipelineData::Value(Value::CustomValue { val, span }, ..) => {
                 let base_pipeline = val.to_base_value(span)?.into_pipeline_data();
                 self.run(engine_state, stack, call, base_pipeline)

crates/nu-protocol/src/cli_error.rs

@@ -1,5 +1,5 @@
+use crate::engine::StateWorkingSet;
 use miette::{LabeledSpan, MietteHandler, ReportHandler, Severity, SourceCode};
-use nu_protocol::engine::StateWorkingSet;
 use thiserror::Error;
 
 /// This error exists so that we can defer SourceCode handling. It simply
@@ -11,6 +11,13 @@ pub struct CliError<'src>(
     pub &'src StateWorkingSet<'src>,
 );
 
+pub fn format_error(
+    working_set: &StateWorkingSet,
+    error: &(dyn miette::Diagnostic + Send + Sync + 'static),
+) -> String {
+    return format!("Error: {:?}", CliError(error, working_set));
+}
+
 impl std::fmt::Debug for CliError<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         MietteHandler::default().debug(self, f)?;

crates/nu-protocol/src/lib.rs

@@ -1,4 +1,5 @@
 pub mod ast;
+mod cli_error;
 mod config;
 pub mod engine;
 mod example;
@@ -14,6 +15,7 @@ mod ty;
 mod value;
 mod variable;
 
+pub use cli_error::*;
 pub use config::*;
 pub use engine::{ENV_VARIABLE_ID, IN_VARIABLE_ID, NU_VARIABLE_ID};
 pub use example::*;

crates/nu-protocol/src/pipeline_data.rs

@@ -455,11 +455,6 @@ impl PipelineData {
 
                 for item in table {
                     let stdout = std::io::stdout();
-
-                    if let Value::Error { error } = item {
-                        return Err(error);
-                    }
-
                     let mut out = item.into_string("\n", config);
                     out.push('\n');
 
@@ -472,11 +467,6 @@ impl PipelineData {
             None => {
                 for item in self {
                     let stdout = std::io::stdout();
-
-                    if let Value::Error { error } = item {
-                        return Err(error);
-                    }
-
                     let mut out = item.into_string("\n", config);
                     out.push('\n');