diff --git a/CHANGELOG.md b/CHANGELOG.md index c7e02aaf4e18..1f2c4f310de2 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -2006,6 +2006,7 @@ Released 2018-09-13 [`possible_missing_comma`]: https://rust-lang.github.io/rust-clippy/master/index.html#possible_missing_comma [`precedence`]: https://rust-lang.github.io/rust-clippy/master/index.html#precedence [`print_literal`]: https://rust-lang.github.io/rust-clippy/master/index.html#print_literal +[`print_stderr`]: https://rust-lang.github.io/rust-clippy/master/index.html#print_stderr [`print_stdout`]: https://rust-lang.github.io/rust-clippy/master/index.html#print_stdout [`print_with_newline`]: https://rust-lang.github.io/rust-clippy/master/index.html#print_with_newline [`println_empty_string`]: https://rust-lang.github.io/rust-clippy/master/index.html#println_empty_string diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index 2b99ed570b14..0e630a352fea 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -934,6 +934,7 @@ 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, @@ -1247,6 +1248,7 @@ 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), ]); diff --git a/clippy_lints/src/write.rs b/clippy_lints/src/write.rs index ff414f748ef9..337f7a229b90 100644 --- a/clippy_lints/src/write.rs +++ b/clippy_lints/src/write.rs @@ -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. diff --git a/tests/ui/eprint_with_newline.rs b/tests/ui/eprint_with_newline.rs new file mode 100644 index 000000000000..8df32649ad94 --- /dev/null +++ b/tests/ui/eprint_with_newline.rs @@ -0,0 +1,49 @@ +#![allow(clippy::print_literal)] +#![warn(clippy::print_with_newline)] + +fn main() { + eprint!("Hello\n"); + eprint!("Hello {}\n", "world"); + eprint!("Hello {} {}\n", "world", "#2"); + eprint!("{}\n", 1265); + eprint!("\n"); + + // these are all fine + eprint!(""); + eprint!("Hello"); + eprintln!("Hello"); + eprintln!("Hello\n"); + eprintln!("Hello {}\n", "world"); + eprint!("Issue\n{}", 1265); + eprint!("{}", 1265); + eprint!("\n{}", 1275); + eprint!("\n\n"); + eprint!("like eof\n\n"); + eprint!("Hello {} {}\n\n", "world", "#2"); + eprintln!("\ndon't\nwarn\nfor\nmultiple\nnewlines\n"); // #3126 + eprintln!("\nbla\n\n"); // #3126 + + // Escaping + eprint!("\\n"); // #3514 + eprint!("\\\n"); // should fail + eprint!("\\\\n"); + + // Raw strings + eprint!(r"\n"); // #3778 + + // Literal newlines should also fail + eprint!( + " +" + ); + eprint!( + r" +" + ); + + // Don't warn on CRLF (#4208) + eprint!("\r\n"); + eprint!("foo\r\n"); + eprint!("\\r\n"); //~ ERROR + eprint!("foo\rbar\n") // ~ ERROR +} diff --git a/tests/ui/eprint_with_newline.stderr b/tests/ui/eprint_with_newline.stderr new file mode 100644 index 000000000000..31811d1d92a0 --- /dev/null +++ b/tests/ui/eprint_with_newline.stderr @@ -0,0 +1,121 @@ +error: using `eprint!()` with a format string that ends in a single newline + --> $DIR/eprint_with_newline.rs:5:5 + | +LL | eprint!("Hello/n"); + | ^^^^^^^^^^^^^^^^^^ + | + = note: `-D clippy::print-with-newline` implied by `-D warnings` +help: use `eprintln!` instead + | +LL | eprintln!("Hello"); + | ^^^^^^^^ -- + +error: using `eprint!()` with a format string that ends in a single newline + --> $DIR/eprint_with_newline.rs:6:5 + | +LL | eprint!("Hello {}/n", "world"); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: use `eprintln!` instead + | +LL | eprintln!("Hello {}", "world"); + | ^^^^^^^^ -- + +error: using `eprint!()` with a format string that ends in a single newline + --> $DIR/eprint_with_newline.rs:7:5 + | +LL | eprint!("Hello {} {}/n", "world", "#2"); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: use `eprintln!` instead + | +LL | eprintln!("Hello {} {}", "world", "#2"); + | ^^^^^^^^ -- + +error: using `eprint!()` with a format string that ends in a single newline + --> $DIR/eprint_with_newline.rs:8:5 + | +LL | eprint!("{}/n", 1265); + | ^^^^^^^^^^^^^^^^^^^^^ + | +help: use `eprintln!` instead + | +LL | eprintln!("{}", 1265); + | ^^^^^^^^ -- + +error: using `eprint!()` with a format string that ends in a single newline + --> $DIR/eprint_with_newline.rs:9:5 + | +LL | eprint!("/n"); + | ^^^^^^^^^^^^^ + | +help: use `eprintln!` instead + | +LL | eprintln!(); + | ^^^^^^^^ -- + +error: using `eprint!()` with a format string that ends in a single newline + --> $DIR/eprint_with_newline.rs:28:5 + | +LL | eprint!("//n"); // should fail + | ^^^^^^^^^^^^^^^ + | +help: use `eprintln!` instead + | +LL | eprintln!("/"); // should fail + | ^^^^^^^^ -- + +error: using `eprint!()` with a format string that ends in a single newline + --> $DIR/eprint_with_newline.rs:35:5 + | +LL | / eprint!( +LL | | " +LL | | " +LL | | ); + | |_____^ + | +help: use `eprintln!` instead + | +LL | eprintln!( +LL | "" + | + +error: using `eprint!()` with a format string that ends in a single newline + --> $DIR/eprint_with_newline.rs:39:5 + | +LL | / eprint!( +LL | | r" +LL | | " +LL | | ); + | |_____^ + | +help: use `eprintln!` instead + | +LL | eprintln!( +LL | r"" + | + +error: using `eprint!()` with a format string that ends in a single newline + --> $DIR/eprint_with_newline.rs:47:5 + | +LL | eprint!("/r/n"); //~ ERROR + | ^^^^^^^^^^^^^^^^ + | +help: use `eprintln!` instead + | +LL | eprintln!("/r"); //~ ERROR + | ^^^^^^^^ -- + +error: using `eprint!()` with a format string that ends in a single newline + --> $DIR/eprint_with_newline.rs:48:5 + | +LL | eprint!("foo/rbar/n") // ~ ERROR + | ^^^^^^^^^^^^^^^^^^^^^ + | +help: use `eprintln!` instead + | +LL | eprintln!("foo/rbar") // ~ ERROR + | ^^^^^^^^ -- + +error: aborting due to 10 previous errors + diff --git a/tests/ui/print_stderr.rs b/tests/ui/print_stderr.rs new file mode 100644 index 000000000000..fa07e74a7be4 --- /dev/null +++ b/tests/ui/print_stderr.rs @@ -0,0 +1,8 @@ +#![warn(clippy::print_stderr)] + +fn main() { + eprintln!("Hello"); + println!("This should not do anything"); + eprint!("World"); + print!("Nor should this"); +} diff --git a/tests/ui/print_stderr.stderr b/tests/ui/print_stderr.stderr new file mode 100644 index 000000000000..5af735af6576 --- /dev/null +++ b/tests/ui/print_stderr.stderr @@ -0,0 +1,16 @@ +error: use of `eprintln!` + --> $DIR/print_stderr.rs:4:5 + | +LL | eprintln!("Hello"); + | ^^^^^^^^^^^^^^^^^^ + | + = note: `-D clippy::print-stderr` implied by `-D warnings` + +error: use of `eprint!` + --> $DIR/print_stderr.rs:6:5 + | +LL | eprint!("World"); + | ^^^^^^^^^^^^^^^^ + +error: aborting due to 2 previous errors + diff --git a/tests/ui/println_empty_string.fixed b/tests/ui/println_empty_string.fixed index 2b889b62ea99..9760680927a6 100644 --- a/tests/ui/println_empty_string.fixed +++ b/tests/ui/println_empty_string.fixed @@ -8,4 +8,11 @@ fn main() { match "a" { _ => println!(), } + + eprintln!(); + eprintln!(); + + match "a" { + _ => eprintln!(), + } } diff --git a/tests/ui/println_empty_string.rs b/tests/ui/println_empty_string.rs index 890f5f684760..80fdb3e6e210 100644 --- a/tests/ui/println_empty_string.rs +++ b/tests/ui/println_empty_string.rs @@ -8,4 +8,11 @@ fn main() { match "a" { _ => println!(""), } + + eprintln!(); + eprintln!(""); + + match "a" { + _ => eprintln!(""), + } } diff --git a/tests/ui/println_empty_string.stderr b/tests/ui/println_empty_string.stderr index 23112b881689..17fe4ea74790 100644 --- a/tests/ui/println_empty_string.stderr +++ b/tests/ui/println_empty_string.stderr @@ -12,5 +12,17 @@ error: using `println!("")` LL | _ => println!(""), | ^^^^^^^^^^^^ help: replace it with: `println!()` -error: aborting due to 2 previous errors +error: using `eprintln!("")` + --> $DIR/println_empty_string.rs:13:5 + | +LL | eprintln!(""); + | ^^^^^^^^^^^^^ help: replace it with: `eprintln!()` + +error: using `eprintln!("")` + --> $DIR/println_empty_string.rs:16:14 + | +LL | _ => eprintln!(""), + | ^^^^^^^^^^^^^ help: replace it with: `eprintln!()` + +error: aborting due to 4 previous errors