Rust 1.73.0 clippy updates

buildpacks/ruby/src/layers/metrics_agent_install.rs

@@ -201,7 +201,7 @@ fn write_execd_script(
 }
 
 fn install_agentmon(dir: &Path) -> Result<PathBuf, MetricsAgentInstallError> {
-    let agentmon = download_untar(DOWNLOAD_URL, dir).map(|_| dir.join("agentmon"))?;
+    let agentmon = download_untar(DOWNLOAD_URL, dir).map(|()| dir.join("agentmon"))?;
 
     chmod_plus_x(&agentmon).map_err(MetricsAgentInstallError::PermissionError)?;
     Ok(agentmon)

buildpacks/ruby/src/layers/ruby_install_layer.rs

@@ -132,7 +132,7 @@ fn download_url(stack: &StackId, version: impl std::fmt::Display) -> Result<Url,
     let mut url = Url::parse(base).map_err(RubyInstallError::UrlParseError)?;
 
     url.path_segments_mut()
-        .map_err(|_| RubyInstallError::InvalidBaseUrl(String::from(base)))?
+        .map_err(|()| RubyInstallError::InvalidBaseUrl(String::from(base)))?
         .push(stack)
         .push(&filename);
     Ok(url)

commons/src/output/build_log.rs

@@ -240,7 +240,7 @@ where
         formatted.push('\n');
 
         match crate::output::warn_later::try_push(formatted) {
-            Ok(_) => {}
+            Ok(()) => {}
             Err(error) => {
                 eprintln!("[Buildpack Warning]: Cannot use the delayed warning feature due to error: {error}");
                 self.log_warning_shared(s);

commons/src/output/fmt.rs

@@ -1,5 +1,6 @@
 use crate::output::util::LinesWithEndings;
 use const_format::formatcp;
+use std::fmt::Write;
 
 /// Helpers for formatting and colorizing your output
 
@@ -119,17 +120,18 @@ pub(crate) fn prefix_indent(prefix: impl AsRef<str>, contents: impl AsRef<str>)
     let prefix = prefix.as_ref();
     let contents = contents.as_ref();
     let non_whitespace_re = regex::Regex::new("\\S").expect("Clippy");
-    let clean_prefix = strip_control_codes(prefix.clone());
+    let clean_prefix = strip_control_codes(prefix);
 
     let indent_str = non_whitespace_re.replace_all(&clean_prefix, " "); // Preserve whitespace characters like tab and space, replace all characters with spaces
     let lines = LinesWithEndings::from(contents).collect::<Vec<_>>();
 
     if let Some((first, rest)) = lines.split_first() {
         format!(
             "{prefix}{first}{}",
-            rest.iter()
-                .map(|line| format!("{indent_str}{line}"))
-                .collect::<String>()
+            rest.iter().fold(String::new(), |mut output, line| {
+                let _ = write!(output, "{indent_str}{line}");
+                output
+            })
         )
     } else {
         prefix.to_string()

commons/src/output/util.rs

@@ -155,6 +155,7 @@ pub(crate) fn strip_trailing_whitespace(s: impl AsRef<str>) -> String {
 #[cfg(test)]
 mod test {
     use super::*;
+    use std::fmt::Write;
 
     #[test]
     fn test_trailing_whitespace() {
@@ -167,15 +168,18 @@ mod test {
 
     #[test]
     fn test_lines_with_endings() {
-        let actual = LinesWithEndings::from("foo\nbar")
-            .map(|line| format!("z{line}"))
-            .collect::<String>();
+        let actual = LinesWithEndings::from("foo\nbar").fold(String::new(), |mut output, line| {
+            let _ = write!(output, "z{line}");
+            output
+        });
 
         assert_eq!("zfoo\nzbar", actual);
 
-        let actual = LinesWithEndings::from("foo\nbar\n")
-            .map(|line| format!("z{line}"))
-            .collect::<String>();
+        let actual =
+            LinesWithEndings::from("foo\nbar\n").fold(String::new(), |mut output, line| {
+                let _ = write!(output, "z{line}");
+                output
+            });
 
         assert_eq!("zfoo\nzbar\n", actual);
     }