Ues strip_prefix for cleaner code

rust-lang · Sep 6, 2023 · 1c6e57e · 1c6e57e
1 parent 84544d4
commit 1c6e57e
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Showing 5 changed files with 18 additions and 15 deletions.
diff --git a/crates/cargo-test-support/src/publish.rs b/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()

diff --git a/src/bin/cargo/main.rs b/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() },
                 );
             }

diff --git a/src/cargo/core/resolver/encode.rs b/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"))?;

diff --git a/src/cargo/util/config/de.rs b/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"`

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