Ues strip_prefix for cleaner code

crates/cargo-platform/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cargo-platform"
-version = "0.1.4"
+version = "0.1.5"
 edition.workspace = true
 license.workspace = true
 homepage = "https://github.com/rust-lang/cargo"

crates/cargo-platform/examples/matches.rs

@@ -35,8 +35,8 @@ fn get_target() -> String {
  .expect("rustc failed to run");
  let stdout = String::from_utf8(output.stdout).unwrap();
  for line in stdout.lines() {
- if line.starts_with("host: ") {
- return String::from(&line[6..]);
+ if let Some(line) = line.strip_prefix("host: ") {
+ return String::from(line);
  }
  }
  panic!("Failed to find host: {}", stdout);

crates/cargo-platform/src/lib.rs

@@ -126,8 +126,7 @@ impl FromStr for Platform {
  type Err = ParseError;
 
  fn from_str(s: &str) -> Result<Platform, ParseError> {
- if s.starts_with("cfg(") && s.ends_with(')') {
- let s = &s[4..s.len() - 1];
+ if let Some(s) = s.strip_prefix("cfg(").and_then(|s| s.strip_suffix(')')) {
  s.parse().map(Platform::Cfg)
  } else {
  Platform::validate_named_platform(s)?;

crates/cargo-test-support/src/publish.rs

@@ -131,8 +131,11 @@ pub fn validate_crate_contents(
  (name, contents)
  })
  .collect();
- assert!(expected_crate_name.ends_with(".crate"));
- let base_crate_name = Path::new(&expected_crate_name[..expected_crate_name.len() - 6]);
+ let base_crate_name = Path::new(
+ expected_crate_name
+ .strip_suffix(".crate")
+ .expect("must end with .crate"),
+ );
  let actual_files: HashSet<PathBuf> = files.keys().cloned().collect();
  let expected_files: HashSet<PathBuf> = expected_files
  .iter()

src/bin/cargo/main.rs

@@ -106,17 +106,18 @@ fn list_commands(config: &Config) -> BTreeMap<String, CommandInfo> {
  };
  for entry in entries.filter_map(|e| e.ok()) {
  let path = entry.path();
- let filename = match path.file_name().and_then(|s| s.to_str()) {
- Some(filename) => filename,
- _ => continue,
+ let Some(filename) = path.file_name().and_then(|s| s.to_str()) else {
+ continue;
  };
- if !filename.starts_with(prefix) || !filename.ends_with(suffix) {
+ let Some(name) = filename
+ .strip_prefix(prefix)
+ .and_then(|s| s.strip_suffix(suffix))
+ else {
  continue;
- }
+ };
  if is_executable(entry.path()) {
- let end = filename.len() - suffix.len();
  commands.insert(
- filename[prefix.len()..end].to_string(),
+ name.to_string(),
  CommandInfo::External { path: path.clone() },
  );
  }

src/cargo/core/resolver/encode.rs

@@ -338,7 +338,7 @@ impl EncodableResolve {
  let mut to_remove = Vec::new();
  for (k, v) in metadata.iter().filter(|p| p.0.starts_with(prefix)) {
  to_remove.push(k.to_string());
- let k = &k[prefix.len()..];
+ let k = k.strip_prefix(prefix).unwrap();
  let enc_id: EncodablePackageId = k
  .parse()
  .with_context(|| internal("invalid encoding of checksum in lockfile"))?;
@@ -601,8 +601,8 @@ impl FromStr for EncodablePackageId {
  let version = s.next();
  let source_id = match s.next() {
  Some(s) => {
- if s.starts_with('(') && s.ends_with(')') {
- Some(SourceId::from_url(&s[1..s.len() - 1])?)
+ if let Some(s) = s.strip_prefix('(').and_then(|s| s.strip_suffix(')')) {
+ Some(SourceId::from_url(s)?)
  } else {
  anyhow::bail!("invalid serialized PackageId")
  }

src/cargo/util/config/de.rs

@@ -216,9 +216,8 @@ impl<'config> ConfigMapAccess<'config> {
  // `CARGO_PROFILE_DEV_PACKAGE_`
  let env_prefix = format!("{}_", de.key.as_env_key());
  for env_key in de.config.env_keys() {
- if env_key.starts_with(&env_prefix) {
- // `CARGO_PROFILE_DEV_PACKAGE_bar_OPT_LEVEL = 3`
- let rest = &env_key[env_prefix.len()..];
+ // `CARGO_PROFILE_DEV_PACKAGE_bar_OPT_LEVEL = 3`
+ if let Some(rest) = env_key.strip_prefix(&env_prefix) {
  // `rest = bar_OPT_LEVEL`
  let part = rest.splitn(2, '_').next().unwrap();
  // `part = "bar"`

src/cargo/util/rustc.rs

@@ -63,8 +63,7 @@ impl Rustc {
  let extract = |field: &str| -> CargoResult<&str> {
  verbose_version
  .lines()
- .find(|l| l.starts_with(field))
- .map(|l| &l[field.len()..])
+ .find_map(|l| l.strip_prefix(field))
  .ok_or_else(|| {
  anyhow::format_err!(
  "`rustc -vV` didn't have a line for `{}`, got:\n{}",

tests/testsuite/install.rs

@@ -2292,9 +2292,9 @@ fn failed_install_retains_temp_directory() {
  .unwrap();
 
  // Find the path in the output.
- let start = stderr.find("found at `").unwrap() + 10;
- let end = stderr[start..].find('.').unwrap() - 1;
- let path = Path::new(&stderr[start..(end + start)]);
+ let stderr = stderr.split_once("found at `").unwrap().1;
+ let end = stderr.find('.').unwrap() - 1;
+ let path = Path::new(&stderr[..end]);
  assert!(path.exists());
  assert!(path.join("release/deps").exists());
 }

tests/testsuite/lto.rs

@@ -453,10 +453,8 @@ fn verify_lto(output: &Output, krate: &str, krate_info: &str, expected_lto: Lto)
  krate, krate_info, line, line2, stderr
  );
  }
- let actual_lto = if let Some(index) = line.find("-C lto=") {
- let s = &line[index..];
- let end = s.find(' ').unwrap();
- let mode = &line[index..index + end];
+ let actual_lto = if let Some((_, line)) = line.split_once("-C lto=") {
+ let mode = line.splitn(2, ' ').next().unwrap();
  if mode == "off" {
  Lto::Off
  } else {

tests/testsuite/ssh.rs

@@ -184,10 +184,9 @@ fn known_host_works() {
  // Validate the fingerprint while we're here.
  let fingerprint = stderr
  .lines()
- .find(|line| line.starts_with(" The ECDSA key fingerprint"))
+ .find_map(|line| line.strip_prefix(" The ECDSA key fingerprint is: "))
  .unwrap()
  .trim();
- let fingerprint = &fingerprint[30..];
  let finger_out = sshd.exec(&["ssh-keygen", "-l", "-f", "/etc/ssh/ssh_host_ecdsa_key.pub"]);
  let gen_finger = std::str::from_utf8(&finger_out.stdout).unwrap();
  // <key-size> <fingerprint> <comments…>