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new lint: zombie_processes

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y21 2023-09-10 16:14:20 +02:00
parent 603d5a19c9
commit e8ac4ea418
14 changed files with 642 additions and 3 deletions
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1
CHANGELOG.md
View file

@ -6048,6 +6048,7 @@ Released 2018-09-13
[`zero_repeat_side_effects`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_repeat_side_effects
[`zero_sized_map_values`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_sized_map_values
[`zero_width_space`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_width_space
[`zombie_processes`]: https://rust-lang.github.io/rust-clippy/master/index.html#zombie_processes
[`zst_offset`]: https://rust-lang.github.io/rust-clippy/master/index.html#zst_offset
<!-- end autogenerated links to lint list -->
<!-- begin autogenerated links to configuration documentation -->

3
clippy_dev/src/serve.rs
View file

@ -29,7 +29,7 @@ pub fn run(port: u16, lint: Option<String>) -> ! {
}
if let Some(url) = url.take() {
thread::spawn(move || {
Command::new(PYTHON)
let mut child = Command::new(PYTHON)
.arg("-m")
.arg("http.server")
.arg(port.to_string())
@ -40,6 +40,7 @@ pub fn run(port: u16, lint: Option<String>) -> ! {
thread::sleep(Duration::from_millis(500));
// Launch browser after first export.py has completed and http.server is up
let _result = opener::open(url);
child.wait().unwrap();
});
}
thread::sleep(Duration::from_millis(1000));

1
clippy_lints/src/declared_lints.rs
View file

@ -768,4 +768,5 @@ pub static LINTS: &[&crate::LintInfo] = &[
crate::zero_div_zero::ZERO_DIVIDED_BY_ZERO_INFO,
crate::zero_repeat_side_effects::ZERO_REPEAT_SIDE_EFFECTS_INFO,
crate::zero_sized_map_values::ZERO_SIZED_MAP_VALUES_INFO,
crate::zombie_processes::ZOMBIE_PROCESSES_INFO,
];

2
clippy_lints/src/lib.rs
View file

@ -386,6 +386,7 @@ mod write;
mod zero_div_zero;
mod zero_repeat_side_effects;
mod zero_sized_map_values;
mod zombie_processes;
// end lints modules, do not remove this comment, it’s used in `update_lints`
use clippy_config::{get_configuration_metadata, Conf};
@ -933,5 +934,6 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
store.register_late_pass(|_| Box::new(set_contains_or_insert::SetContainsOrInsert));
store.register_early_pass(|| Box::new(byte_char_slices::ByteCharSlice));
store.register_early_pass(|| Box::new(cfg_not_test::CfgNotTest));
store.register_late_pass(|_| Box::new(zombie_processes::ZombieProcesses));
// add lints here, do not remove this comment, it's used in `new_lint`
}

334
clippy_lints/src/zombie_processes.rs Normal file
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@ -0,0 +1,334 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::{fn_def_id, get_enclosing_block, match_any_def_paths, match_def_path, path_to_local_id, paths};
use rustc_ast::Mutability;
use rustc_errors::Applicability;
use rustc_hir::intravisit::{walk_block, walk_expr, walk_local, Visitor};
use rustc_hir::{Expr, ExprKind, HirId, LetStmt, Node, PatKind, Stmt, StmtKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::declare_lint_pass;
use rustc_span::sym;
use std::ops::ControlFlow;
use ControlFlow::{Break, Continue};
declare_clippy_lint! {
/// ### What it does
/// Looks for code that spawns a process but never calls `wait()` on the child.
///
/// ### Why is this bad?
/// As explained in the [standard library documentation](https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning),
/// calling `wait()` is necessary on Unix platforms to properly release all OS resources associated with the process.
/// Not doing so will effectively leak process IDs and/or other limited global resources,
/// which can eventually lead to resource exhaustion, so it's recommended to call `wait()` in long-running applications.
/// Such processes are called "zombie processes".
///
/// ### Example
/// ```rust
/// use std::process::Command;
///
/// let _child = Command::new("ls").spawn().expect("failed to execute child");
/// ```
/// Use instead:
/// ```rust
/// use std::process::Command;
///
/// let mut child = Command::new("ls").spawn().expect("failed to execute child");
/// child.wait().expect("failed to wait on child");
/// ```
#[clippy::version = "1.74.0"]
pub ZOMBIE_PROCESSES,
suspicious,
"not waiting on a spawned child process"
}
declare_lint_pass!(ZombieProcesses => [ZOMBIE_PROCESSES]);
impl<'tcx> LateLintPass<'tcx> for ZombieProcesses {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
if let ExprKind::Call(..) | ExprKind::MethodCall(..) = expr.kind
&& let Some(child_adt) = cx.typeck_results().expr_ty(expr).ty_adt_def()
&& match_def_path(cx, child_adt.did(), &paths::CHILD)
{
match cx.tcx.parent_hir_node(expr.hir_id) {
Node::LetStmt(local)
if let PatKind::Binding(_, local_id, ..) = local.pat.kind
&& let Some(enclosing_block) = get_enclosing_block(cx, expr.hir_id) =>
{
let mut vis = WaitFinder::WalkUpTo(cx, local_id);
// If it does have a `wait()` call, we're done. Don't lint.
if let Break(BreakReason::WaitFound) = walk_block(&mut vis, enclosing_block) {
return;
}
// Don't emit a suggestion since the binding is used later
check(cx, expr, false);
},
Node::LetStmt(&LetStmt { pat, .. }) if let PatKind::Wild = pat.kind => {
// `let _ = child;`, also dropped immediately without `wait()`ing
check(cx, expr, true);
},
Node::Stmt(&Stmt {
kind: StmtKind::Semi(_),
..
}) => {
// Immediately dropped. E.g. `std::process::Command::new("echo").spawn().unwrap();`
check(cx, expr, true);
},
_ => {},
}
}
}
}
enum BreakReason {
WaitFound,
EarlyReturn,
}
/// A visitor responsible for finding a `wait()` call on a local variable.
///
/// Conditional `wait()` calls are assumed to not call wait:
/// ```ignore
/// let mut c = Command::new("").spawn().unwrap();
/// if true {
/// c.wait();
/// }
/// ```
///
/// Note that this visitor does NOT explicitly look for `wait()` calls directly, but rather does the
/// inverse -- checking if all uses of the local are either:
/// - a field access (`child.{stderr,stdin,stdout}`)
/// - calling `id` or `kill`
/// - no use at all (e.g. `let _x = child;`)
/// - taking a shared reference (`&`), `wait()` can't go through that
///
/// None of these are sufficient to prevent zombie processes.
/// Doing it like this means more FNs, but FNs are better than FPs.
///
/// `return` expressions, conditional or not, short-circuit the visitor because
/// if a `wait()` call hadn't been found at that point, it might never reach one at a later point:
/// ```ignore
/// let mut c = Command::new("").spawn().unwrap();
/// if true {
/// return; // Break(BreakReason::EarlyReturn)
/// }
/// c.wait(); // this might not be reachable
/// ```
enum WaitFinder<'a, 'tcx> {
WalkUpTo(&'a LateContext<'tcx>, HirId),
Found(&'a LateContext<'tcx>, HirId),
}
impl<'a, 'tcx> Visitor<'tcx> for WaitFinder<'a, 'tcx> {
type Result = ControlFlow<BreakReason>;
fn visit_local(&mut self, l: &'tcx LetStmt<'tcx>) -> Self::Result {
if let Self::WalkUpTo(cx, local_id) = *self
&& let PatKind::Binding(_, pat_id, ..) = l.pat.kind
&& local_id == pat_id
{
*self = Self::Found(cx, local_id);
}
walk_local(self, l)
}
fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) -> Self::Result {
let Self::Found(cx, local_id) = *self else {
return walk_expr(self, ex);
};
if path_to_local_id(ex, local_id) {
match cx.tcx.parent_hir_node(ex.hir_id) {
Node::Stmt(Stmt {
kind: StmtKind::Semi(_),
..
}) => {},
Node::Expr(expr) if let ExprKind::Field(..) = expr.kind => {},
Node::Expr(expr) if let ExprKind::AddrOf(_, Mutability::Not, _) = expr.kind => {},
Node::Expr(expr)
if let Some(fn_did) = fn_def_id(cx, expr)
&& match_any_def_paths(cx, fn_did, &[&paths::CHILD_ID, &paths::CHILD_KILL]).is_some() => {},
// Conservatively assume that all other kinds of nodes call `.wait()` somehow.
_ => return Break(BreakReason::WaitFound),
}
} else {
match ex.kind {
ExprKind::Ret(..) => return Break(BreakReason::EarlyReturn),
ExprKind::If(cond, then, None) => {
walk_expr(self, cond)?;
// A `wait()` call in an if expression with no else is not enough:
//
// let c = spawn();
// if true {
// c.wait();
// }
//
// This might not call wait(). However, early returns are propagated,
// because they might lead to a later wait() not being called.
if let Break(BreakReason::EarlyReturn) = walk_expr(self, then) {
return Break(BreakReason::EarlyReturn);
}
return Continue(());
},
ExprKind::If(cond, then, Some(else_)) => {
walk_expr(self, cond)?;
#[expect(clippy::unnested_or_patterns)]
match (walk_expr(self, then), walk_expr(self, else_)) {
(Continue(()), Continue(()))
// `wait()` in one branch but nothing in the other does not count
| (Continue(()), Break(BreakReason::WaitFound))
| (Break(BreakReason::WaitFound), Continue(())) => {},
// `wait()` in both branches is ok
(Break(BreakReason::WaitFound), Break(BreakReason::WaitFound)) => {
return Break(BreakReason::WaitFound);
},
// Propagate early returns in either branch
(Break(BreakReason::EarlyReturn), _) | (_, Break(BreakReason::EarlyReturn)) => {
return Break(BreakReason::EarlyReturn);
},
}
return Continue(());
},
_ => {},
}
}
walk_expr(self, ex)
}
}
/// This function has shared logic between the different kinds of nodes that can trigger the lint.
///
/// In particular, `let <binding> = <expr that spawns child>;` requires some custom additional logic
/// such as checking that the binding is not used in certain ways, which isn't necessary for
/// `let _ = <expr that spawns child>;`.
///
/// This checks if the program doesn't unconditionally exit after the spawn expression.
fn check<'tcx>(cx: &LateContext<'tcx>, spawn_expr: &'tcx Expr<'tcx>, emit_suggestion: bool) {
let Some(block) = get_enclosing_block(cx, spawn_expr.hir_id) else {
return;
};
let mut vis = ExitPointFinder {
cx,
state: ExitPointState::WalkUpTo(spawn_expr.hir_id),
};
if let Break(ExitCallFound) = vis.visit_block(block) {
// Visitor found an unconditional `exit()` call, so don't lint.
return;
}
span_lint_and_then(
cx,
ZOMBIE_PROCESSES,
spawn_expr.span,
"spawned process is never `wait()`ed on",
|diag| {
if emit_suggestion {
diag.span_suggestion(
spawn_expr.span.shrink_to_hi(),
"try",
".wait()",
Applicability::MaybeIncorrect,
);
} else {
diag.note("consider calling `.wait()`");
}
diag.note("not doing so might leave behind zombie processes")
.note("see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning");
},
);
}
/// Checks if the given expression exits the process.
fn is_exit_expression(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
fn_def_id(cx, expr).is_some_and(|fn_did| {
cx.tcx.is_diagnostic_item(sym::process_exit, fn_did) || match_def_path(cx, fn_did, &paths::ABORT)
})
}
#[derive(Debug)]
enum ExitPointState {
/// Still walking up to the expression that initiated the visitor.
WalkUpTo(HirId),
/// We're inside of a control flow construct (e.g. `if`, `match`, `loop`)
/// Within this, we shouldn't accept any `exit()` calls in here, but we can leave all of these
/// constructs later and still continue looking for an `exit()` call afterwards. Example:
/// ```ignore
/// Command::new("").spawn().unwrap();
///
/// if true { // depth=1
/// if true { // depth=2
/// match () { // depth=3
/// () => loop { // depth=4
///
/// std::process::exit();
/// ^^^^^^^^^^^^^^^^^^^^^ conditional exit call, ignored
///
/// } // depth=3
/// } // depth=2
/// } // depth=1
/// } // depth=0
///
/// std::process::exit();
/// ^^^^^^^^^^^^^^^^^^^^^ this exit call is accepted because we're now unconditionally calling it
/// ```
/// We can only get into this state from `NoExit`.
InControlFlow { depth: u32 },
/// No exit call found yet, but looking for one.
NoExit,
}
fn expr_enters_control_flow(expr: &Expr<'_>) -> bool {
matches!(expr.kind, ExprKind::If(..) | ExprKind::Match(..) | ExprKind::Loop(..))
}
struct ExitPointFinder<'a, 'tcx> {
state: ExitPointState,
cx: &'a LateContext<'tcx>,
}
struct ExitCallFound;
impl<'a, 'tcx> Visitor<'tcx> for ExitPointFinder<'a, 'tcx> {
type Result = ControlFlow<ExitCallFound>;
fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) -> Self::Result {
match self.state {
ExitPointState::WalkUpTo(id) if expr.hir_id == id => {
self.state = ExitPointState::NoExit;
walk_expr(self, expr)
},
ExitPointState::NoExit if expr_enters_control_flow(expr) => {
self.state = ExitPointState::InControlFlow { depth: 1 };
walk_expr(self, expr)?;
if let ExitPointState::InControlFlow { .. } = self.state {
self.state = ExitPointState::NoExit;
}
Continue(())
},
ExitPointState::NoExit if is_exit_expression(self.cx, expr) => Break(ExitCallFound),
ExitPointState::InControlFlow { ref mut depth } if expr_enters_control_flow(expr) => {
*depth += 1;
walk_expr(self, expr)?;
match self.state {
ExitPointState::InControlFlow { depth: 1 } => self.state = ExitPointState::NoExit,
ExitPointState::InControlFlow { ref mut depth } => *depth -= 1,
_ => {},
}
Continue(())
},
_ => Continue(()),
}
}
}

4
clippy_utils/src/paths.rs
View file

@ -4,6 +4,7 @@
//! Whenever possible, please consider diagnostic items over hardcoded paths.
//! See <https://github.com/rust-lang/rust-clippy/issues/5393> for more information.
pub const ABORT: [&str; 3] = ["std", "process", "abort"];
pub const APPLICABILITY: [&str; 2] = ["rustc_lint_defs", "Applicability"];
pub const APPLICABILITY_VALUES: [[&str; 3]; 4] = [
["rustc_lint_defs", "Applicability", "Unspecified"],
@ -23,6 +24,9 @@ pub const CORE_RESULT_OK_METHOD: [&str; 4] = ["core", "result", "Result", "ok"];
pub const CSTRING_AS_C_STR: [&str; 5] = ["alloc", "ffi", "c_str", "CString", "as_c_str"];
pub const EARLY_CONTEXT: [&str; 2] = ["rustc_lint", "EarlyContext"];
pub const EARLY_LINT_PASS: [&str; 3] = ["rustc_lint", "passes", "EarlyLintPass"];
pub const CHILD: [&str; 3] = ["std", "process", "Child"];
pub const CHILD_ID: [&str; 4] = ["std", "process", "Child", "id"];
pub const CHILD_KILL: [&str; 4] = ["std", "process", "Child", "kill"];
pub const F32_EPSILON: [&str; 4] = ["core", "f32", "<impl f32>", "EPSILON"];
pub const F64_EPSILON: [&str; 4] = ["core", "f64", "<impl f64>", "EPSILON"];
pub const FILE_OPTIONS: [&str; 4] = ["std", "fs", "File", "options"];

1
tests/ui/suspicious_command_arg_space.fixed
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@ -1,3 +1,4 @@
#![allow(clippy::zombie_processes)]
fn main() {
// Things it should warn about:
std::process::Command::new("echo").args(["-n", "hello"]).spawn().unwrap();

1
tests/ui/suspicious_command_arg_space.rs
View file

@ -1,3 +1,4 @@
#![allow(clippy::zombie_processes)]
fn main() {
// Things it should warn about:
std::process::Command::new("echo").arg("-n hello").spawn().unwrap();

4
tests/ui/suspicious_command_arg_space.stderr
View file

@ -1,5 +1,5 @@
error: single argument that looks like it should be multiple arguments
--> tests/ui/suspicious_command_arg_space.rs:3:44
--> tests/ui/suspicious_command_arg_space.rs:4:44
|
LL | std::process::Command::new("echo").arg("-n hello").spawn().unwrap();
| ^^^^^^^^^^
@ -12,7 +12,7 @@ LL | std::process::Command::new("echo").args(["-n", "hello"]).spawn().unwrap
| ~~~~ ~~~~~~~~~~~~~~~
error: single argument that looks like it should be multiple arguments
--> tests/ui/suspicious_command_arg_space.rs:6:43
--> tests/ui/suspicious_command_arg_space.rs:7:43
|
LL | std::process::Command::new("cat").arg("--number file").spawn().unwrap();
| ^^^^^^^^^^^^^^^

138
tests/ui/zombie_processes.rs Normal file
View file

@ -0,0 +1,138 @@
#![warn(clippy::zombie_processes)]
#![allow(clippy::if_same_then_else, clippy::ifs_same_cond)]
use std::process::{Child, Command};
fn main() {
{
// Check that #[expect] works
#[expect(clippy::zombie_processes)]
let mut x = Command::new("").spawn().unwrap();
}
{
let mut x = Command::new("").spawn().unwrap();
//~^ ERROR: spawned process is never `wait()`ed on
x.kill();
x.id();
}
{
let mut x = Command::new("").spawn().unwrap();
x.wait().unwrap(); // OK
}
{
let x = Command::new("").spawn().unwrap();
x.wait_with_output().unwrap(); // OK
}
{
let mut x = Command::new("").spawn().unwrap();
x.try_wait().unwrap(); // OK
}
{
let mut x = Command::new("").spawn().unwrap();
let mut r = &mut x;
r.wait().unwrap(); // OK, not calling `.wait()` directly on `x` but through `r` -> `x`
}
{
let mut x = Command::new("").spawn().unwrap();
process_child(x); // OK, other function might call `.wait()` so assume it does
}
{
let mut x = Command::new("").spawn().unwrap();
//~^ ERROR: spawned process is never `wait()`ed on
let v = &x;
// (allow shared refs is fine because one cannot call `.wait()` through that)
}
// https://github.com/rust-lang/rust-clippy/pull/11476#issuecomment-1718456033
// Unconditionally exiting the process in various ways (should not lint)
{
let mut x = Command::new("").spawn().unwrap();
std::process::exit(0);
}
{
let mut x = Command::new("").spawn().unwrap();
std::process::abort(); // same as above, but abort instead of exit
}
{
let mut x = Command::new("").spawn().unwrap();
if true { /* nothing */ }
std::process::abort(); // still unconditionally exits
}
// Conditionally exiting
// It should assume that it might not exit and still lint
{
let mut x = Command::new("").spawn().unwrap();
//~^ ERROR: spawned process is never `wait()`ed on
if true {
std::process::exit(0);
}
}
{
let mut x = Command::new("").spawn().unwrap();
//~^ ERROR: spawned process is never `wait()`ed on
if true {
while false {}
// Calling `exit()` after leaving a while loop should still be linted.
std::process::exit(0);
}
}
{
let mut x = { Command::new("").spawn().unwrap() };
x.wait().unwrap();
}
{
struct S {
c: Child,
}
let mut s = S {
c: Command::new("").spawn().unwrap(),
};
s.c.wait().unwrap();
}
{
let mut x = Command::new("").spawn().unwrap();
//~^ ERROR: spawned process is never `wait()`ed on
if true {
return;
}
x.wait().unwrap();
}
{
let mut x = Command::new("").spawn().unwrap();
//~^ ERROR: spawned process is never `wait()`ed on
if true {
x.wait().unwrap();
}
}
{
let mut x = Command::new("").spawn().unwrap();
if true {
x.wait().unwrap();
} else if true {
x.wait().unwrap();
} else {
x.wait().unwrap();
}
}
{
let mut x = Command::new("").spawn().unwrap();
if true {
x.wait().unwrap();
return;
}
x.wait().unwrap();
}
}
fn process_child(c: Child) {
todo!()
}

64
tests/ui/zombie_processes.stderr Normal file
View file

@ -0,0 +1,64 @@
error: spawned process is never `wait()`ed on
--> tests/ui/zombie_processes.rs:14:21
|
LL | let mut x = Command::new("").spawn().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: consider calling `.wait()`
= note: not doing so might leave behind zombie processes
= note: see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning
= note: `-D clippy::zombie-processes` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::zombie_processes)]`
error: spawned process is never `wait()`ed on
--> tests/ui/zombie_processes.rs:41:21
|
LL | let mut x = Command::new("").spawn().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: consider calling `.wait()`
= note: not doing so might leave behind zombie processes
= note: see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning
error: spawned process is never `wait()`ed on
--> tests/ui/zombie_processes.rs:66:21
|
LL | let mut x = Command::new("").spawn().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: consider calling `.wait()`
= note: not doing so might leave behind zombie processes
= note: see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning
error: spawned process is never `wait()`ed on
--> tests/ui/zombie_processes.rs:73:21
|
LL | let mut x = Command::new("").spawn().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: consider calling `.wait()`
= note: not doing so might leave behind zombie processes
= note: see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning
error: spawned process is never `wait()`ed on
--> tests/ui/zombie_processes.rs:99:21
|
LL | let mut x = Command::new("").spawn().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: consider calling `.wait()`
= note: not doing so might leave behind zombie processes
= note: see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning
error: spawned process is never `wait()`ed on
--> tests/ui/zombie_processes.rs:108:21
|
LL | let mut x = Command::new("").spawn().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: consider calling `.wait()`
= note: not doing so might leave behind zombie processes
= note: see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning
error: aborting due to 6 previous errors

26
tests/ui/zombie_processes_fixable.fixed Normal file
View file

@ -0,0 +1,26 @@
#![warn(clippy::zombie_processes)]
#![allow(clippy::needless_return)]
use std::process::{Child, Command};
fn main() {
let _ = Command::new("").spawn().unwrap().wait();
//~^ ERROR: spawned process is never `wait()`ed on
Command::new("").spawn().unwrap().wait();
//~^ ERROR: spawned process is never `wait()`ed on
spawn_proc().wait();
//~^ ERROR: spawned process is never `wait()`ed on
spawn_proc().wait().unwrap(); // OK
}
fn not_main() {
Command::new("").spawn().unwrap().wait();
}
fn spawn_proc() -> Child {
Command::new("").spawn().unwrap()
}
fn spawn_proc_2() -> Child {
return Command::new("").spawn().unwrap();
}

26
tests/ui/zombie_processes_fixable.rs Normal file
View file

@ -0,0 +1,26 @@
#![warn(clippy::zombie_processes)]
#![allow(clippy::needless_return)]
use std::process::{Child, Command};
fn main() {
let _ = Command::new("").spawn().unwrap();
//~^ ERROR: spawned process is never `wait()`ed on
Command::new("").spawn().unwrap();
//~^ ERROR: spawned process is never `wait()`ed on
spawn_proc();
//~^ ERROR: spawned process is never `wait()`ed on
spawn_proc().wait().unwrap(); // OK
}
fn not_main() {
Command::new("").spawn().unwrap();
}
fn spawn_proc() -> Child {
Command::new("").spawn().unwrap()
}
fn spawn_proc_2() -> Child {
return Command::new("").spawn().unwrap();
}

40
tests/ui/zombie_processes_fixable.stderr Normal file
View file

@ -0,0 +1,40 @@
error: spawned process is never `wait()`ed on
--> tests/ui/zombie_processes_fixable.rs:7:13
|
LL | let _ = Command::new("").spawn().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- help: try: `.wait()`
|
= note: not doing so might leave behind zombie processes
= note: see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning
= note: `-D clippy::zombie-processes` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::zombie_processes)]`
error: spawned process is never `wait()`ed on
--> tests/ui/zombie_processes_fixable.rs:9:5
|
LL | Command::new("").spawn().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- help: try: `.wait()`
|
= note: not doing so might leave behind zombie processes
= note: see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning
error: spawned process is never `wait()`ed on
--> tests/ui/zombie_processes_fixable.rs:11:5
|
LL | spawn_proc();
| ^^^^^^^^^^^^- help: try: `.wait()`
|
= note: not doing so might leave behind zombie processes
= note: see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning
error: spawned process is never `wait()`ed on
--> tests/ui/zombie_processes_fixable.rs:17:5
|
LL | Command::new("").spawn().unwrap();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- help: try: `.wait()`
|
= note: not doing so might leave behind zombie processes
= note: see https://doc.rust-lang.org/stable/std/process/struct.Child.html#warning
error: aborting due to 4 previous errors