user0/rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Auto merge of #6367 - justjosias:6348-print-stderr, r=ebroto

Browse source 
Add lint print_stderr

Resolves #6348
Almost identical to print_stdout, this lint applies to the `eprintln!` and `eprint!` macros rather than `println!` and `print!`.

changelog: Add new lint [`print_stderr`]. [`println_empty_string`] and [`print_with_newline`] now apply to `eprint!()` and `eprintln!()` respectively.
This commit is contained in:
bors 2020-12-08 22:22:49 +00:00
commit b02b0c737a
10 changed files with 294 additions and 38 deletions
Download patch file Download diff file Expand all files Collapse all files

2
clippy_lints/src/lib.rs
View file

@ -936,6 +936,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
&wildcard_imports::WILDCARD_IMPORTS,
&write::PRINTLN_EMPTY_STRING,
&write::PRINT_LITERAL,
&write::PRINT_STDERR,
&write::PRINT_STDOUT,
&write::PRINT_WITH_NEWLINE,
&write::USE_DEBUG,
@ -1250,6 +1251,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
LintId::of(&types::RC_BUFFER),
LintId::of(&unwrap_in_result::UNWRAP_IN_RESULT),
LintId::of(&verbose_file_reads::VERBOSE_FILE_READS),
LintId::of(&write::PRINT_STDERR),
LintId::of(&write::PRINT_STDOUT),
LintId::of(&write::USE_DEBUG),
]);

107
clippy_lints/src/write.rs
View file

@ -75,6 +75,24 @@ declare_clippy_lint! {
"printing on stdout"
}
declare_clippy_lint! {
/// **What it does:** Checks for printing on *stderr*. The purpose of this lint
/// is to catch debugging remnants.
///
/// **Why is this bad?** People often print on *stderr* while debugging an
/// application and might forget to remove those prints afterward.
///
/// **Known problems:** Only catches `eprint!` and `eprintln!` calls.
///
/// **Example:**
/// ```rust
/// eprintln!("Hello world!");
/// ```
pub PRINT_STDERR,
restriction,
"printing on stderr"
}
declare_clippy_lint! {
/// **What it does:** Checks for use of `Debug` formatting. The purpose of this
/// lint is to catch debugging remnants.
@ -201,6 +219,7 @@ impl_lint_pass!(Write => [
PRINT_WITH_NEWLINE,
PRINTLN_EMPTY_STRING,
PRINT_STDOUT,
PRINT_STDERR,
USE_DEBUG,
PRINT_LITERAL,
WRITE_WITH_NEWLINE,
@ -243,47 +262,22 @@ impl EarlyLintPass for Write {
.map_or(false, |crate_name| crate_name == "build_script_build")
}
if mac.path == sym!(println) {
if !is_build_script(cx) {
span_lint(cx, PRINT_STDOUT, mac.span(), "use of `println!`");
}
if let (Some(fmt_str), _) = self.check_tts(cx, mac.args.inner_tokens(), false) {
if fmt_str.symbol == Symbol::intern("") {
span_lint_and_sugg(
cx,
PRINTLN_EMPTY_STRING,
mac.span(),
"using `println!(\"\")`",
"replace it with",
"println!()".to_string(),
Applicability::MachineApplicable,
);
}
}
} else if mac.path == sym!(print) {
if mac.path == sym!(print) {
if !is_build_script(cx) {
span_lint(cx, PRINT_STDOUT, mac.span(), "use of `print!`");
}
if let (Some(fmt_str), _) = self.check_tts(cx, mac.args.inner_tokens(), false) {
if check_newlines(&fmt_str) {
span_lint_and_then(
cx,
PRINT_WITH_NEWLINE,
mac.span(),
"using `print!()` with a format string that ends in a single newline",
|err| {
err.multipart_suggestion(
"use `println!` instead",
vec![
(mac.path.span, String::from("println")),
(newline_span(&fmt_str), String::new()),
],
Applicability::MachineApplicable,
);
},
);
}
self.lint_print_with_newline(cx, mac);
} else if mac.path == sym!(println) {
if !is_build_script(cx) {
span_lint(cx, PRINT_STDOUT, mac.span(), "use of `println!`");
}
self.lint_println_empty_string(cx, mac);
} else if mac.path == sym!(eprint) {
span_lint(cx, PRINT_STDERR, mac.span(), "use of `eprint!`");
self.lint_print_with_newline(cx, mac);
} else if mac.path == sym!(eprintln) {
span_lint(cx, PRINT_STDERR, mac.span(), "use of `eprintln!`");
self.lint_println_empty_string(cx, mac);
} else if mac.path == sym!(write) {
if let (Some(fmt_str), _) = self.check_tts(cx, mac.args.inner_tokens(), true) {
if check_newlines(&fmt_str) {
@ -487,6 +481,45 @@ impl Write {
}
}
}
fn lint_println_empty_string(&self, cx: &EarlyContext<'_>, mac: &MacCall) {
if let (Some(fmt_str), _) = self.check_tts(cx, mac.args.inner_tokens(), false) {
if fmt_str.symbol == Symbol::intern("") {
let name = mac.path.segments[0].ident.name;
span_lint_and_sugg(
cx,
PRINTLN_EMPTY_STRING,
mac.span(),
&format!("using `{}!(\"\")`", name),
"replace it with",
format!("{}!()", name),
Applicability::MachineApplicable,
);
}
}
}
fn lint_print_with_newline(&self, cx: &EarlyContext<'_>, mac: &MacCall) {
if let (Some(fmt_str), _) = self.check_tts(cx, mac.args.inner_tokens(), false) {
if check_newlines(&fmt_str) {
let name = mac.path.segments[0].ident.name;
let suggested = format!("{}ln", name);
span_lint_and_then(
cx,
PRINT_WITH_NEWLINE,
mac.span(),
&format!("using `{}!()` with a format string that ends in a single newline", name),
|err| {
err.multipart_suggestion(
&format!("use `{}!` instead", suggested),
vec![(mac.path.span, suggested), (newline_span(&fmt_str), String::new())],
Applicability::MachineApplicable,
);
},
);
}
}
}
}
/// Checks if the format string contains a single newline that terminates it.