Use c"lit" for CStrings without unwrap

Author: kornelski

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -148,7 +148,7 @@ fn prepare_lto(
     // __llvm_profile_counter_bias is pulled in at link time by an undefined reference to
     // __llvm_profile_runtime, therefore we won't know until link time if this symbol
     // should have default visibility.
-    symbols_below_threshold.push(CString::new("__llvm_profile_counter_bias").unwrap());
+    symbols_below_threshold.push(c"__llvm_profile_counter_bias".to_owned());
     Ok((symbols_below_threshold, upstream_modules))
 }
 

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -509,7 +509,7 @@ fn get_pgo_sample_use_path(config: &ModuleConfig) -> Option<CString> {
 }
 
 fn get_instr_profile_output_path(config: &ModuleConfig) -> Option<CString> {
-    config.instrument_coverage.then(|| CString::new("default_%m_%p.profraw").unwrap())
+    config.instrument_coverage.then(|| c"default_%m_%p.profraw".to_owned())
 }
 
 pub(crate) unsafe fn llvm_optimize(

compiler/rustc_error_codes/src/error_codes/E0060.md

@@ -23,16 +23,11 @@ simply calling `printf()` is invalid. But the following uses are allowed:
 # extern "C" { fn printf(_: *const c_char, ...) -> c_int; }
 # fn main() {
 unsafe {
-    use std::ffi::CString;
+    printf(c"test\n");
 
-    let fmt = CString::new("test\n").unwrap();
-    printf(fmt.as_ptr());
+    printf(c"number = %d\n", 3);
 
-    let fmt = CString::new("number = %d\n").unwrap();
-    printf(fmt.as_ptr(), 3);
-
-    let fmt = CString::new("%d, %d\n").unwrap();
-    printf(fmt.as_ptr(), 10, 5);
+    printf(c"%d, %d\n", 10, 5);
 }
 # }
 ```

library/alloc/src/ffi/c_str.rs

@@ -384,7 +384,7 @@ impl CString {
     ///     fn some_extern_function(s: *mut c_char);
     /// }
     ///
-    /// let c_string = CString::new("Hello!").expect("CString::new failed");
+    /// let c_string = CString::from(c"Hello!");
     /// let raw = c_string.into_raw();
     /// unsafe {
     ///     some_extern_function(raw);
@@ -429,7 +429,7 @@ impl CString {
     /// ```
     /// use std::ffi::CString;
     ///
-    /// let c_string = CString::new("foo").expect("CString::new failed");
+    /// let c_string = CString::from(c"foo");
     ///
     /// let ptr = c_string.into_raw();
     ///
@@ -487,7 +487,7 @@ impl CString {
     /// ```
     /// use std::ffi::CString;
     ///
-    /// let c_string = CString::new("foo").expect("CString::new failed");
+    /// let c_string = CString::from(c"foo");
     /// let bytes = c_string.into_bytes();
     /// assert_eq!(bytes, vec![b'f', b'o', b'o']);
     /// ```
@@ -508,7 +508,7 @@ impl CString {
     /// ```
     /// use std::ffi::CString;
     ///
-    /// let c_string = CString::new("foo").expect("CString::new failed");
+    /// let c_string = CString::from(c"foo");
     /// let bytes = c_string.into_bytes_with_nul();
     /// assert_eq!(bytes, vec![b'f', b'o', b'o', b'\0']);
     /// ```
@@ -530,7 +530,7 @@ impl CString {
     /// ```
     /// use std::ffi::CString;
     ///
-    /// let c_string = CString::new("foo").expect("CString::new failed");
+    /// let c_string = CString::from(c"foo");
     /// let bytes = c_string.as_bytes();
     /// assert_eq!(bytes, &[b'f', b'o', b'o']);
     /// ```
@@ -550,7 +550,7 @@ impl CString {
     /// ```
     /// use std::ffi::CString;
     ///
-    /// let c_string = CString::new("foo").expect("CString::new failed");
+    /// let c_string = CString::from(c"foo");
     /// let bytes = c_string.as_bytes_with_nul();
     /// assert_eq!(bytes, &[b'f', b'o', b'o', b'\0']);
     /// ```
@@ -568,7 +568,7 @@ impl CString {
     /// ```
     /// use std::ffi::{CString, CStr};
     ///
-    /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed");
+    /// let c_string = CString::from(c"foo");
     /// let cstr = c_string.as_c_str();
     /// assert_eq!(cstr,
     ///            CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed"));
@@ -586,12 +586,9 @@ impl CString {
     /// # Examples
     ///
     /// ```
-    /// use std::ffi::{CString, CStr};
-    ///
-    /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed");
+    /// let c_string = c"foo".to_owned();
     /// let boxed = c_string.into_boxed_c_str();
-    /// assert_eq!(&*boxed,
-    ///            CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed"));
+    /// assert_eq!(boxed.to_bytes_with_nul(), b"foo\0");
     /// ```
     #[must_use = "`self` will be dropped if the result is not used"]
     #[stable(feature = "into_boxed_c_str", since = "1.20.0")]
@@ -658,7 +655,7 @@ impl CString {
     /// assert_eq!(
     ///     CString::from_vec_with_nul(b"abc\0".to_vec())
     ///         .expect("CString::from_vec_with_nul failed"),
-    ///     CString::new(b"abc".to_vec()).expect("CString::new failed")
+    ///     c"abc".to_owned()
     /// );
     /// ```
     ///
@@ -1168,11 +1165,12 @@ impl CStr {
     /// # Examples
     ///
     /// ```
-    /// use std::ffi::CString;
+    /// use std::ffi::{CStr, CString};
     ///
-    /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed");
-    /// let boxed = c_string.into_boxed_c_str();
-    /// assert_eq!(boxed.into_c_string(), CString::new("foo").expect("CString::new failed"));
+    /// let boxed: Box<CStr> = Box::from(c"foo");
+    /// let c_string: CString = c"foo".to_owned();
+    ///
+    /// assert_eq!(boxed.into_c_string(), c_string);
     /// ```
     #[rustc_allow_incoherent_impl]
     #[must_use = "`self` will be dropped if the result is not used"]

library/alloc/src/ffi/c_str/tests.rs

@@ -159,7 +159,7 @@ fn boxed_default() {
 
 #[test]
 fn test_c_str_clone_into() {
-    let mut c_string = CString::new("lorem").unwrap();
+    let mut c_string = c"lorem".to_owned();
     let c_ptr = c_string.as_ptr();
     let c_str = CStr::from_bytes_with_nul(b"ipsum\0").unwrap();
     c_str.clone_into(&mut c_string);

library/alloc/src/rc/tests.rs

@@ -349,9 +349,9 @@ fn test_unsized() {
 #[test]
 fn test_maybe_thin_unsized() {
     // If/when custom thin DSTs exist, this test should be updated to use one
-    use std::ffi::{CStr, CString};
+    use std::ffi::CStr;
 
-    let x: Rc<CStr> = Rc::from(CString::new("swordfish").unwrap().into_boxed_c_str());
+    let x: Rc<CStr> = Rc::from(c"swordfish");
     assert_eq!(format!("{x:?}"), "\"swordfish\"");
     let y: Weak<CStr> = Rc::downgrade(&x);
     drop(x);

library/alloc/src/sync/tests.rs

@@ -412,9 +412,9 @@ fn test_unsized() {
 #[test]
 fn test_maybe_thin_unsized() {
     // If/when custom thin DSTs exist, this test should be updated to use one
-    use std::ffi::{CStr, CString};
+    use std::ffi::CStr;
 
-    let x: Arc<CStr> = Arc::from(CString::new("swordfish").unwrap().into_boxed_c_str());
+    let x: Arc<CStr> = Arc::from(c"swordfish");
     assert_eq!(format!("{x:?}"), "\"swordfish\"");
     let y: Weak<CStr> = Arc::downgrade(&x);
     drop(x);

library/std/src/sys/pal/unix/process/process_common.rs

@@ -393,7 +393,7 @@ impl Command {
 fn os2c(s: &OsStr, saw_nul: &mut bool) -> CString {
     CString::new(s.as_bytes()).unwrap_or_else(|_e| {
         *saw_nul = true;
-        CString::new("<string-with-nul>").unwrap()
+        c"<string-with-nul>".to_owned()
     })
 }
 

src/tools/miri/tests/pass-dep/libc/libc-fs-symlink.rs

@@ -47,9 +47,8 @@ fn test_readlink() {
     assert_eq!(res, small_buf.len() as isize);
 
     // Test that we report a proper error for a missing path.
-    let bad_path = CString::new("MIRI_MISSING_FILE_NAME").unwrap();
     let res = unsafe {
-        libc::readlink(bad_path.as_ptr(), small_buf.as_mut_ptr().cast(), small_buf.len())
+        libc::readlink(c"MIRI_MISSING_FILE_NAME".as_ptr(), small_buf.as_mut_ptr().cast(), small_buf.len())
     };
     assert_eq!(res, -1);
     assert_eq!(Error::last_os_error().kind(), ErrorKind::NotFound);

src/tools/miri/tests/pass-dep/libc/libc-fs-with-isolation.rs

@@ -2,7 +2,6 @@
 //@compile-flags: -Zmiri-isolation-error=warn-nobacktrace
 //@normalize-stderr-test: "(stat(x)?)" -> "$$STAT"
 
-use std::ffi::CString;
 use std::fs;
 use std::io::{Error, ErrorKind};
 
@@ -13,10 +12,9 @@ fn main() {
     }
 
     // test `readlink`
-    let symlink_c_str = CString::new("foo.txt").unwrap();
     let mut buf = vec![0; "foo_link.txt".len() + 1];
     unsafe {
-        assert_eq!(libc::readlink(symlink_c_str.as_ptr(), buf.as_mut_ptr(), buf.len()), -1);
+        assert_eq!(libc::readlink(c"foo.txt".as_ptr(), buf.as_mut_ptr(), buf.len()), -1);
         assert_eq!(Error::last_os_error().raw_os_error(), Some(libc::EACCES));
     }
 

src/tools/miri/tests/pass-dep/libc/libc-mem.rs

@@ -55,12 +55,12 @@ fn test_memcpy() {
 }
 
 fn test_strcpy() {
-    use std::ffi::{CStr, CString};
+    use std::ffi::CStr;
 
     // case: src_size equals dest_size
     unsafe {
-        let src = CString::new("rust").unwrap();
-        let size = src.as_bytes_with_nul().len();
+        let src = c"rust";
+        let size = src.to_bytes_with_nul().len();
         let dest = libc::malloc(size);
         libc::strcpy(dest as *mut libc::c_char, src.as_ptr());
         assert_eq!(CStr::from_ptr(dest as *const libc::c_char), src.as_ref());
@@ -69,8 +69,8 @@ fn test_strcpy() {
 
     // case: src_size is less than dest_size
     unsafe {
-        let src = CString::new("rust").unwrap();
-        let size = src.as_bytes_with_nul().len();
+        let src = c"rust";
+        let size = src.to_bytes_with_nul().len();
         let dest = libc::malloc(size + 1);
         libc::strcpy(dest as *mut libc::c_char, src.as_ptr());
         assert_eq!(CStr::from_ptr(dest as *const libc::c_char), src.as_ref());

src/tools/rust-analyzer/crates/profile/src/memory_usage.rs

@@ -69,8 +69,7 @@ fn memusage_linux() -> MemoryUsage {
 
     let mut mallinfo2 = MALLINFO2.load(Ordering::Relaxed);
     if mallinfo2 == 1 {
-        let cstr = CStr::from_bytes_with_nul(b"mallinfo2\0").unwrap();
-        mallinfo2 = unsafe { libc::dlsym(libc::RTLD_DEFAULT, cstr.as_ptr()) } as usize;
+        mallinfo2 = unsafe { libc::dlsym(libc::RTLD_DEFAULT, c"mallinfo2".as_ptr()) } as usize;
         // NB: races don't matter here, since they'll always store the same value
         MALLINFO2.store(mallinfo2, Ordering::Relaxed);
     }

tests/run-make/libtest-thread-limit/rmake.rs

@@ -38,7 +38,7 @@ fn main() {
     // If the process ID is 0, this is the child process responsible for running the test
     // program.
     if pid == 0 {
-        let test = CString::new("test").unwrap();
+        let test = c"test";
         // The argv array should be terminated with a NULL pointer.
         let argv = [test.as_ptr(), std::ptr::null()];
         // rlim_cur is soft limit, rlim_max is hard limit.

tests/ui/process/env-funky-keys.rs

@@ -1,4 +1,5 @@
 //@ run-pass
+//@ edition: 2021
 // Ignore this test on Android, because it segfaults there.
 
 //@ ignore-android
@@ -32,10 +33,9 @@ fn main() {
                                        .unwrap()
                                        .as_os_str()
                                        .as_bytes()).unwrap();
-    let new_env_var = CString::new("FOOBAR").unwrap();
     let filename: *const c_char = current_exe.as_ptr();
     let argv: &[*const c_char] = &[filename, filename, ptr::null()];
-    let envp: &[*const c_char] = &[new_env_var.as_ptr(), ptr::null()];
+    let envp: &[*const c_char] = &[c"FOOBAR".as_ptr(), ptr::null()];
     unsafe {
         execve(filename, &argv[0], &envp[0]);
     }