nushell/crates/nu-engine/src/eval.rs
Sophia June Turner 2ffe30ecf0
Respect non-zero exit code in subexpressions and blocks (#8984)
# Description

This PR changes the way we handled non-zero exit codes to be and early
exit between `foo; bar`. If `foo` in the example has a non-zero exit
code, `bar` wouldn't be run.

This also affects subexpressions.
2023-12-05 14:42:55 +08:00

1148 lines
40 KiB
Rust

use crate::{current_dir_str, get_full_help};
use nu_path::expand_path_with;
use nu_protocol::{
ast::{
Argument, Assignment, Block, Call, Expr, Expression, PathMember, PipelineElement,
Redirection,
},
engine::{Closure, EngineState, Stack},
eval_base::Eval,
DeclId, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData, ShellError, Span,
Spanned, Type, Value, VarId, ENV_VARIABLE_ID,
};
use std::collections::HashMap;
use std::thread::{self, JoinHandle};
pub fn eval_call(
engine_state: &EngineState,
caller_stack: &mut Stack,
call: &Call,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
if nu_utils::ctrl_c::was_pressed(&engine_state.ctrlc) {
return Ok(Value::nothing(call.head).into_pipeline_data());
}
let decl = engine_state.get_decl(call.decl_id);
if !decl.is_known_external() && call.named_iter().any(|(flag, _, _)| flag.item == "help") {
let mut signature = engine_state.get_signature(decl);
signature.usage = decl.usage().to_string();
signature.extra_usage = decl.extra_usage().to_string();
let full_help = get_full_help(
&signature,
&decl.examples(),
engine_state,
caller_stack,
decl.is_parser_keyword(),
);
Ok(Value::string(full_help, call.head).into_pipeline_data())
} else if let Some(block_id) = decl.get_block_id() {
let block = engine_state.get_block(block_id);
let mut callee_stack = caller_stack.gather_captures(engine_state, &block.captures);
for (param_idx, param) in decl
.signature()
.required_positional
.iter()
.chain(decl.signature().optional_positional.iter())
.enumerate()
{
let var_id = param
.var_id
.expect("internal error: all custom parameters must have var_ids");
if let Some(arg) = call.positional_nth(param_idx) {
let result = eval_expression(engine_state, caller_stack, arg)?;
callee_stack.add_var(var_id, result);
} else if let Some(value) = &param.default_value {
callee_stack.add_var(var_id, value.to_owned());
} else {
callee_stack.add_var(var_id, Value::nothing(call.head));
}
}
if let Some(rest_positional) = decl.signature().rest_positional {
let mut rest_items = vec![];
for arg in call.positional_iter().skip(
decl.signature().required_positional.len()
+ decl.signature().optional_positional.len(),
) {
let result = eval_expression(engine_state, caller_stack, arg)?;
rest_items.push(result);
}
let span = if let Some(rest_item) = rest_items.first() {
rest_item.span()
} else {
call.head
};
callee_stack.add_var(
rest_positional
.var_id
.expect("Internal error: rest positional parameter lacks var_id"),
Value::list(rest_items, span),
)
}
for named in decl.signature().named {
if let Some(var_id) = named.var_id {
let mut found = false;
for call_named in call.named_iter() {
if let (Some(spanned), Some(short)) = (&call_named.1, named.short) {
if spanned.item == short.to_string() {
if let Some(arg) = &call_named.2 {
let result = eval_expression(engine_state, caller_stack, arg)?;
callee_stack.add_var(var_id, result);
} else if let Some(value) = &named.default_value {
callee_stack.add_var(var_id, value.to_owned());
} else {
callee_stack.add_var(var_id, Value::bool(true, call.head))
}
found = true;
}
} else if call_named.0.item == named.long {
if let Some(arg) = &call_named.2 {
let result = eval_expression(engine_state, caller_stack, arg)?;
callee_stack.add_var(var_id, result);
} else if let Some(value) = &named.default_value {
callee_stack.add_var(var_id, value.to_owned());
} else {
callee_stack.add_var(var_id, Value::bool(true, call.head))
}
found = true;
}
}
if !found {
if named.arg.is_none() {
callee_stack.add_var(var_id, Value::bool(false, call.head))
} else if let Some(value) = named.default_value {
callee_stack.add_var(var_id, value);
} else {
callee_stack.add_var(var_id, Value::nothing(call.head))
}
}
}
}
let result = eval_block_with_early_return(
engine_state,
&mut callee_stack,
block,
input,
call.redirect_stdout,
call.redirect_stderr,
);
if block.redirect_env {
redirect_env(engine_state, caller_stack, &callee_stack);
}
result
} else {
// We pass caller_stack here with the knowledge that internal commands
// are going to be specifically looking for global state in the stack
// rather than any local state.
decl.run(engine_state, caller_stack, call, input)
}
}
/// Redirect the environment from callee to the caller.
pub fn redirect_env(engine_state: &EngineState, caller_stack: &mut Stack, callee_stack: &Stack) {
// Grab all environment variables from the callee
let caller_env_vars = caller_stack.get_env_var_names(engine_state);
// remove env vars that are present in the caller but not in the callee
// (the callee hid them)
for var in caller_env_vars.iter() {
if !callee_stack.has_env_var(engine_state, var) {
caller_stack.remove_env_var(engine_state, var);
}
}
// add new env vars from callee to caller
for (var, value) in callee_stack.get_stack_env_vars() {
caller_stack.add_env_var(var, value);
}
}
enum RedirectTarget {
Piped(bool, bool),
CombinedPipe,
}
#[allow(clippy::too_many_arguments)]
fn eval_external(
engine_state: &EngineState,
stack: &mut Stack,
head: &Expression,
args: &[Expression],
input: PipelineData,
redirect_target: RedirectTarget,
is_subexpression: bool,
) -> Result<PipelineData, ShellError> {
let decl_id = engine_state
.find_decl("run-external".as_bytes(), &[])
.ok_or(ShellError::ExternalNotSupported { span: head.span })?;
let command = engine_state.get_decl(decl_id);
let mut call = Call::new(head.span);
call.add_positional(head.clone());
for arg in args {
call.add_positional(arg.clone())
}
match redirect_target {
RedirectTarget::Piped(redirect_stdout, redirect_stderr) => {
if redirect_stdout {
call.add_named((
Spanned {
item: "redirect-stdout".into(),
span: head.span,
},
None,
None,
))
}
if redirect_stderr {
call.add_named((
Spanned {
item: "redirect-stderr".into(),
span: head.span,
},
None,
None,
))
}
}
RedirectTarget::CombinedPipe => call.add_named((
Spanned {
item: "redirect-combine".into(),
span: head.span,
},
None,
None,
)),
}
if is_subexpression {
call.add_named((
Spanned {
item: "trim-end-newline".into(),
span: head.span,
},
None,
None,
))
}
command.run(engine_state, stack, &call, input)
}
pub fn eval_expression(
engine_state: &EngineState,
stack: &mut Stack,
expr: &Expression,
) -> Result<Value, ShellError> {
<EvalRuntime as Eval>::eval(engine_state, stack, expr)
}
/// Checks the expression to see if it's a internal or external call. If so, passes the input
/// into the call and gets out the result
/// Otherwise, invokes the expression
///
/// It returns PipelineData with a boolean flag, indicating if the external failed to run.
/// The boolean flag **may only be true** for external calls, for internal calls, it always to be false.
pub fn eval_expression_with_input(
engine_state: &EngineState,
stack: &mut Stack,
expr: &Expression,
mut input: PipelineData,
redirect_stdout: bool,
redirect_stderr: bool,
) -> Result<(PipelineData, bool), ShellError> {
match expr {
Expression {
expr: Expr::Call(call),
..
} => {
if !redirect_stdout || redirect_stderr {
// we're doing something different than the defaults
let mut call = call.clone();
call.redirect_stdout = redirect_stdout;
call.redirect_stderr = redirect_stderr;
input = eval_call(engine_state, stack, &call, input)?;
} else {
input = eval_call(engine_state, stack, call, input)?;
}
}
Expression {
expr: Expr::ExternalCall(head, args, is_subexpression),
..
} => {
input = eval_external(
engine_state,
stack,
head,
args,
input,
RedirectTarget::Piped(redirect_stdout, redirect_stderr),
*is_subexpression,
)?;
}
Expression {
expr: Expr::Subexpression(block_id),
..
} => {
let block = engine_state.get_block(*block_id);
// FIXME: protect this collect with ctrl-c
input = eval_subexpression(engine_state, stack, block, input)?;
}
elem @ Expression {
expr: Expr::FullCellPath(full_cell_path),
..
} => match &full_cell_path.head {
Expression {
expr: Expr::Subexpression(block_id),
span,
..
} => {
let block = engine_state.get_block(*block_id);
// FIXME: protect this collect with ctrl-c
input = eval_subexpression(engine_state, stack, block, input)?;
let value = input.into_value(*span);
input = value
.follow_cell_path(&full_cell_path.tail, false)?
.into_pipeline_data()
}
_ => {
input = eval_expression(engine_state, stack, elem)?.into_pipeline_data();
}
},
elem => {
input = eval_expression(engine_state, stack, elem)?.into_pipeline_data();
}
};
Ok(might_consume_external_result(input))
}
// Try to catch and detect if external command runs to failed.
fn might_consume_external_result(input: PipelineData) -> (PipelineData, bool) {
input.is_external_failed()
}
fn eval_element_with_input(
engine_state: &EngineState,
stack: &mut Stack,
element: &PipelineElement,
mut input: PipelineData,
redirect_stdout: bool,
redirect_stderr: bool,
stderr_writer_jobs: &mut Vec<DataSaveJob>,
) -> Result<(PipelineData, bool), ShellError> {
match element {
PipelineElement::Expression(_, expr) => eval_expression_with_input(
engine_state,
stack,
expr,
input,
redirect_stdout,
redirect_stderr,
),
PipelineElement::Redirection(span, redirection, expr, is_append_mode) => {
match &expr.expr {
Expr::String(_)
| Expr::FullCellPath(_)
| Expr::StringInterpolation(_)
| Expr::Filepath(_) => {
let exit_code = match &mut input {
PipelineData::ExternalStream { exit_code, .. } => exit_code.take(),
_ => None,
};
// when nushell get Stderr Redirection, we want to take `stdout` part of `input`
// so this stdout stream can be handled by next command.
let (input, out_stream) = match (redirection, input) {
(
Redirection::Stderr,
PipelineData::ExternalStream {
stdout,
stderr,
exit_code,
span,
metadata,
trim_end_newline,
},
) => (
PipelineData::ExternalStream {
stdout: stderr,
stderr: None,
exit_code,
span,
metadata,
trim_end_newline,
},
Some(stdout),
),
(_, input) => (input, None),
};
if let Some(save_command) = engine_state.find_decl(b"save", &[]) {
let save_call = gen_save_call(
save_command,
(*span, expr.clone(), *is_append_mode),
None,
);
match out_stream {
None => {
eval_call(engine_state, stack, &save_call, input).map(|_| {
// save is internal command, normally it exists with non-ExternalStream
// but here in redirection context, we make it returns ExternalStream
// So nu handles exit_code correctly
//
// Also, we don't want to run remaining commands if this command exits with non-zero
// exit code, so we need to consume and check exit_code too
might_consume_external_result(PipelineData::ExternalStream {
stdout: None,
stderr: None,
exit_code,
span: *span,
metadata: None,
trim_end_newline: false,
})
})
}
Some(out_stream) => {
// delegate to a different thread
// so nushell won't hang if external command generates both too much
// stderr and stdout message
let stderr_stack = stack.clone();
let engine_state_clone = engine_state.clone();
stderr_writer_jobs.push(DataSaveJob::spawn(
engine_state_clone,
stderr_stack,
save_call,
input,
));
Ok(might_consume_external_result(
PipelineData::ExternalStream {
stdout: out_stream,
stderr: None,
exit_code,
span: *span,
metadata: None,
trim_end_newline: false,
},
))
}
}
} else {
Err(ShellError::CommandNotFound { span: *span })
}
}
_ => Err(ShellError::CommandNotFound { span: *span }),
}
}
PipelineElement::SeparateRedirection {
out: (out_span, out_expr, out_append_mode),
err: (err_span, err_expr, err_append_mode),
} => match (&out_expr.expr, &err_expr.expr) {
(
Expr::String(_)
| Expr::FullCellPath(_)
| Expr::StringInterpolation(_)
| Expr::Filepath(_),
Expr::String(_)
| Expr::FullCellPath(_)
| Expr::StringInterpolation(_)
| Expr::Filepath(_),
) => {
if let Some(save_command) = engine_state.find_decl(b"save", &[]) {
let exit_code = match &mut input {
PipelineData::ExternalStream { exit_code, .. } => exit_code.take(),
_ => None,
};
let save_call = gen_save_call(
save_command,
(*out_span, out_expr.clone(), *out_append_mode),
Some((*err_span, err_expr.clone(), *err_append_mode)),
);
eval_call(engine_state, stack, &save_call, input).map(|_| {
// save is internal command, normally it exists with non-ExternalStream
// but here in redirection context, we make it returns ExternalStream
// So nu handles exit_code correctly
might_consume_external_result(PipelineData::ExternalStream {
stdout: None,
stderr: None,
exit_code,
span: *out_span,
metadata: None,
trim_end_newline: false,
})
})
} else {
Err(ShellError::CommandNotFound { span: *out_span })
}
}
(_out_other, err_other) => {
if let Expr::String(_) = err_other {
Err(ShellError::CommandNotFound { span: *out_span })
} else {
Err(ShellError::CommandNotFound { span: *err_span })
}
}
},
PipelineElement::SameTargetRedirection {
cmd: (cmd_span, cmd_exp),
redirection: (redirect_span, redirect_exp, is_append_mode),
} => {
// general idea: eval cmd and call save command to redirect stdout to result.
input = match &cmd_exp.expr {
Expr::ExternalCall(head, args, is_subexpression) => {
// if cmd's expression is ExternalStream, then invoke run-external with
// special --redirect-combine flag.
eval_external(
engine_state,
stack,
head,
args,
input,
RedirectTarget::CombinedPipe,
*is_subexpression,
)?
}
_ => {
// we need to redirect output, so the result can be saved and pass to `save` command.
eval_element_with_input(
engine_state,
stack,
&PipelineElement::Expression(*cmd_span, cmd_exp.clone()),
input,
true,
redirect_stderr,
stderr_writer_jobs,
)
.map(|x| x.0)?
}
};
eval_element_with_input(
engine_state,
stack,
&PipelineElement::Redirection(
*redirect_span,
Redirection::Stdout,
redirect_exp.clone(),
*is_append_mode,
),
input,
redirect_stdout,
redirect_stderr,
stderr_writer_jobs,
)
}
PipelineElement::And(_, expr) => eval_expression_with_input(
engine_state,
stack,
expr,
input,
redirect_stdout,
redirect_stderr,
),
PipelineElement::Or(_, expr) => eval_expression_with_input(
engine_state,
stack,
expr,
input,
redirect_stdout,
redirect_stderr,
),
}
}
pub fn eval_block_with_early_return(
engine_state: &EngineState,
stack: &mut Stack,
block: &Block,
input: PipelineData,
redirect_stdout: bool,
redirect_stderr: bool,
) -> Result<PipelineData, ShellError> {
match eval_block(
engine_state,
stack,
block,
input,
redirect_stdout,
redirect_stderr,
) {
Err(ShellError::Return(_, value)) => Ok(PipelineData::Value(*value, None)),
x => x,
}
}
pub fn eval_block(
engine_state: &EngineState,
stack: &mut Stack,
block: &Block,
mut input: PipelineData,
mut redirect_stdout: bool,
mut redirect_stderr: bool,
) -> Result<PipelineData, ShellError> {
// if Block contains recursion, make sure we don't recurse too deeply (to avoid stack overflow)
if let Some(recursive) = block.recursive {
// picked 50 arbitrarily, should work on all architectures
const RECURSION_LIMIT: u64 = 50;
if recursive {
if *stack.recursion_count >= RECURSION_LIMIT {
stack.recursion_count = Box::new(0);
return Err(ShellError::RecursionLimitReached {
recursion_limit: RECURSION_LIMIT,
span: block.span,
});
}
*stack.recursion_count += 1;
}
}
let num_pipelines = block.len();
for (pipeline_idx, pipeline) in block.pipelines.iter().enumerate() {
let mut stderr_writer_jobs = vec![];
let elements = &pipeline.elements;
let elements_length = elements.len();
for (idx, element) in elements.iter().enumerate() {
if !redirect_stderr && idx < elements_length - 1 {
let next_element = &elements[idx + 1];
if matches!(
next_element,
PipelineElement::Redirection(_, Redirection::Stderr, _, _)
| PipelineElement::Redirection(_, Redirection::StdoutAndStderr, _, _)
| PipelineElement::SeparateRedirection { .. }
) {
redirect_stderr = true;
}
}
if !redirect_stdout && idx < elements_length - 1 {
let next_element = &elements[idx + 1];
match next_element {
// is next element a stdout relative redirection?
PipelineElement::Redirection(_, Redirection::Stdout, _, _)
| PipelineElement::Redirection(_, Redirection::StdoutAndStderr, _, _)
| PipelineElement::SeparateRedirection { .. }
| PipelineElement::Expression(..) => redirect_stdout = true,
PipelineElement::Redirection(_, Redirection::Stderr, _, _) => {
// a stderr redirection, but we still need to check for the next 2nd
// element, to handle for the following case:
// cat a.txt err> /dev/null | lines
//
// we only need to check the next 2nd element because we already make sure
// that we don't have duplicate err> like this:
// cat a.txt err> /dev/null err> /tmp/a
if idx < elements_length - 2 {
let next_2nd_element = &elements[idx + 2];
if matches!(next_2nd_element, PipelineElement::Expression(..)) {
redirect_stdout = true
}
}
}
_ => {}
}
}
// if eval internal command failed, it can just make early return with `Err(ShellError)`.
let eval_result = eval_element_with_input(
engine_state,
stack,
element,
input,
redirect_stdout,
redirect_stderr,
&mut stderr_writer_jobs,
);
match (eval_result, redirect_stderr) {
(Err(error), true) => {
input = PipelineData::Value(
Value::error(
error,
Span::unknown(), // FIXME: where does this span come from?
),
None,
)
}
(output, _) => {
let output = output?;
input = output.0;
// external command may runs to failed
// make early return so remaining commands will not be executed.
// don't return `Err(ShellError)`, so nushell wouldn't show extra error message.
if output.1 {
return Ok(input);
}
}
}
}
// `eval_element_with_input` may creates some threads
// to write stderr message to a file, here we need to wait and make sure that it's
// finished.
for h in stderr_writer_jobs {
let _ = h.join();
}
if pipeline_idx < (num_pipelines) - 1 {
match input {
PipelineData::Value(Value::Nothing { .. }, ..) => {}
PipelineData::ExternalStream {
ref mut exit_code, ..
} => {
let exit_code = exit_code.take();
input.drain()?;
if let Some(exit_code) = exit_code {
let mut v: Vec<_> = exit_code.collect();
if let Some(v) = v.pop() {
let break_loop = !matches!(v.as_i64(), Ok(0));
stack.add_env_var("LAST_EXIT_CODE".into(), v);
if break_loop {
input = PipelineData::empty();
break;
}
}
}
}
_ => input.drain()?,
}
input = PipelineData::empty()
}
}
Ok(input)
}
pub fn eval_subexpression(
engine_state: &EngineState,
stack: &mut Stack,
block: &Block,
input: PipelineData,
) -> Result<PipelineData, ShellError> {
eval_block(engine_state, stack, block, input, true, false)
}
pub fn eval_variable(
engine_state: &EngineState,
stack: &Stack,
var_id: VarId,
span: Span,
) -> Result<Value, ShellError> {
match var_id {
// $nu
nu_protocol::NU_VARIABLE_ID => {
if let Some(val) = engine_state.get_constant(var_id) {
Ok(val.clone())
} else {
Err(ShellError::VariableNotFoundAtRuntime { span })
}
}
// $env
ENV_VARIABLE_ID => {
let env_vars = stack.get_env_vars(engine_state);
let env_columns = env_vars.keys();
let env_values = env_vars.values();
let mut pairs = env_columns
.map(|x| x.to_string())
.zip(env_values.cloned())
.collect::<Vec<(String, Value)>>();
pairs.sort_by(|a, b| a.0.cmp(&b.0));
Ok(Value::record(pairs.into_iter().collect(), span))
}
var_id => stack.get_var(var_id, span),
}
}
fn gen_save_call(
save_decl_id: DeclId,
out_info: (Span, Expression, bool),
err_info: Option<(Span, Expression, bool)>,
) -> Call {
let (out_span, out_expr, out_append_mode) = out_info;
let mut call = Call {
decl_id: save_decl_id,
head: out_span,
arguments: vec![],
redirect_stdout: false,
redirect_stderr: false,
parser_info: HashMap::new(),
};
let mut args = vec![
Argument::Positional(out_expr),
Argument::Named((
Spanned {
item: "raw".into(),
span: out_span,
},
None,
None,
)),
Argument::Named((
Spanned {
item: "force".into(),
span: out_span,
},
None,
None,
)),
];
if out_append_mode {
call.set_parser_info(
"out-append".to_string(),
Expression {
expr: Expr::Bool(true),
span: out_span,
ty: Type::Bool,
custom_completion: None,
},
);
}
if let Some((err_span, err_expr, err_append_mode)) = err_info {
args.push(Argument::Named((
Spanned {
item: "stderr".into(),
span: err_span,
},
None,
Some(err_expr),
)));
if err_append_mode {
call.set_parser_info(
"err-append".to_string(),
Expression {
expr: Expr::Bool(true),
span: err_span,
ty: Type::Bool,
custom_completion: None,
},
);
}
}
call.arguments.append(&mut args);
call
}
/// A job which saves `PipelineData` to a file in a child thread.
struct DataSaveJob {
inner: JoinHandle<()>,
}
impl DataSaveJob {
pub fn spawn(
engine_state: EngineState,
mut stack: Stack,
save_call: Call,
input: PipelineData,
) -> Self {
Self {
inner: thread::Builder::new()
.name("stderr saver".to_string())
.spawn(move || {
let result = eval_call(&engine_state, &mut stack, &save_call, input);
if let Err(err) = result {
eprintln!("WARNING: error occurred when redirect to stderr: {:?}", err);
}
})
.expect("Failed to create thread"),
}
}
pub fn join(self) -> thread::Result<()> {
self.inner.join()
}
}
struct EvalRuntime;
impl Eval for EvalRuntime {
type State<'a> = &'a EngineState;
type MutState = Stack;
fn eval_filepath(
engine_state: Self::State<'_>,
stack: &mut Self::MutState,
path: String,
span: Span,
) -> Result<Value, ShellError> {
let cwd = current_dir_str(engine_state, stack)?;
let path = expand_path_with(path, cwd);
Ok(Value::string(path.to_string_lossy(), span))
}
fn eval_directory(
engine_state: Self::State<'_>,
stack: &mut Self::MutState,
path: String,
span: Span,
) -> Result<Value, ShellError> {
if path == "-" {
Ok(Value::string("-", span))
} else {
let cwd = current_dir_str(engine_state, stack)?;
let path = expand_path_with(path, cwd);
Ok(Value::string(path.to_string_lossy(), span))
}
}
fn eval_var(
engine_state: &EngineState,
stack: &mut Stack,
var_id: VarId,
span: Span,
) -> Result<Value, ShellError> {
eval_variable(engine_state, stack, var_id, span)
}
fn eval_call(
engine_state: &EngineState,
stack: &mut Stack,
call: &Call,
_: Span,
) -> Result<Value, ShellError> {
// FIXME: protect this collect with ctrl-c
Ok(eval_call(engine_state, stack, call, PipelineData::empty())?.into_value(call.head))
}
fn eval_external_call(
engine_state: &EngineState,
stack: &mut Stack,
head: &Expression,
args: &[Expression],
is_subexpression: bool,
_: Span,
) -> Result<Value, ShellError> {
let span = head.span;
// FIXME: protect this collect with ctrl-c
Ok(eval_external(
engine_state,
stack,
head,
args,
PipelineData::empty(),
RedirectTarget::Piped(false, false),
is_subexpression,
)?
.into_value(span))
}
fn eval_subexpression(
engine_state: &EngineState,
stack: &mut Stack,
block_id: usize,
span: Span,
) -> Result<Value, ShellError> {
let block = engine_state.get_block(block_id);
// FIXME: protect this collect with ctrl-c
Ok(eval_subexpression(engine_state, stack, block, PipelineData::empty())?.into_value(span))
}
fn regex_match(
engine_state: &EngineState,
op_span: Span,
lhs: &Value,
rhs: &Value,
invert: bool,
expr_span: Span,
) -> Result<Value, ShellError> {
lhs.regex_match(engine_state, op_span, rhs, invert, expr_span)
}
fn eval_assignment(
engine_state: &EngineState,
stack: &mut Stack,
lhs: &Expression,
rhs: &Expression,
assignment: Assignment,
op_span: Span,
_expr_span: Span,
) -> Result<Value, ShellError> {
let rhs = eval_expression(engine_state, stack, rhs)?;
let rhs = match assignment {
Assignment::Assign => rhs,
Assignment::PlusAssign => {
let lhs = eval_expression(engine_state, stack, lhs)?;
lhs.add(op_span, &rhs, op_span)?
}
Assignment::MinusAssign => {
let lhs = eval_expression(engine_state, stack, lhs)?;
lhs.sub(op_span, &rhs, op_span)?
}
Assignment::MultiplyAssign => {
let lhs = eval_expression(engine_state, stack, lhs)?;
lhs.mul(op_span, &rhs, op_span)?
}
Assignment::DivideAssign => {
let lhs = eval_expression(engine_state, stack, lhs)?;
lhs.div(op_span, &rhs, op_span)?
}
Assignment::AppendAssign => {
let lhs = eval_expression(engine_state, stack, lhs)?;
lhs.append(op_span, &rhs, op_span)?
}
};
match &lhs.expr {
Expr::Var(var_id) | Expr::VarDecl(var_id) => {
let var_info = engine_state.get_var(*var_id);
if var_info.mutable {
stack.add_var(*var_id, rhs);
Ok(Value::nothing(lhs.span))
} else {
Err(ShellError::AssignmentRequiresMutableVar { lhs_span: lhs.span })
}
}
Expr::FullCellPath(cell_path) => {
match &cell_path.head.expr {
Expr::Var(var_id) | Expr::VarDecl(var_id) => {
// The $env variable is considered "mutable" in Nushell.
// As such, give it special treatment here.
let is_env = var_id == &ENV_VARIABLE_ID;
if is_env || engine_state.get_var(*var_id).mutable {
let mut lhs = eval_expression(engine_state, stack, &cell_path.head)?;
lhs.upsert_data_at_cell_path(&cell_path.tail, rhs)?;
if is_env {
if cell_path.tail.is_empty() {
return Err(ShellError::CannotReplaceEnv {
span: cell_path.head.span,
});
}
// The special $env treatment: for something like $env.config.history.max_size = 2000,
// get $env.config (or whichever one it is) AFTER the above mutation, and set it
// as the "config" environment variable.
let vardata =
lhs.follow_cell_path(&[cell_path.tail[0].clone()], false)?;
match &cell_path.tail[0] {
PathMember::String { val, span, .. } => {
if val == "FILE_PWD"
|| val == "CURRENT_FILE"
|| val == "PWD"
{
return Err(ShellError::AutomaticEnvVarSetManually {
envvar_name: val.to_string(),
span: *span,
});
} else {
stack.add_env_var(val.to_string(), vardata);
}
}
// In case someone really wants an integer env-var
PathMember::Int { val, .. } => {
stack.add_env_var(val.to_string(), vardata);
}
}
} else {
stack.add_var(*var_id, lhs);
}
Ok(Value::nothing(cell_path.head.span))
} else {
Err(ShellError::AssignmentRequiresMutableVar { lhs_span: lhs.span })
}
}
_ => Err(ShellError::AssignmentRequiresVar { lhs_span: lhs.span }),
}
}
_ => Err(ShellError::AssignmentRequiresVar { lhs_span: lhs.span }),
}
}
fn eval_row_condition_or_closure(
engine_state: &EngineState,
stack: &mut Stack,
block_id: usize,
span: Span,
) -> Result<Value, ShellError> {
let captures = engine_state
.get_block(block_id)
.captures
.iter()
.map(|&id| stack.get_var(id, span).map(|var| (id, var)))
.collect::<Result<_, _>>()?;
Ok(Value::closure(Closure { block_id, captures }, span))
}
fn eval_string_interpolation(
engine_state: &EngineState,
stack: &mut Stack,
exprs: &[Expression],
span: Span,
) -> Result<Value, ShellError> {
let mut parts = vec![];
for expr in exprs {
parts.push(eval_expression(engine_state, stack, expr)?);
}
let config = engine_state.get_config();
parts
.into_iter()
.into_pipeline_data(None)
.collect_string("", config)
.map(|x| Value::string(x, span))
}
fn eval_overlay(engine_state: &EngineState, span: Span) -> Result<Value, ShellError> {
let name = String::from_utf8_lossy(engine_state.get_span_contents(span)).to_string();
Ok(Value::string(name, span))
}
fn eval_glob_pattern(
engine_state: Self::State<'_>,
stack: &mut Self::MutState,
pattern: String,
span: Span,
) -> Result<Value, ShellError> {
let cwd = current_dir_str(engine_state, stack)?;
let path = expand_path_with(pattern, cwd);
Ok(Value::string(path.to_string_lossy(), span))
}
fn unreachable(expr: &Expression) -> Result<Value, ShellError> {
Ok(Value::nothing(expr.span))
}
}