chore(clippy): add workspace lints string_slice, await_holding_lock, let_underscore_must_use (#25669)

Co-authored-by: Thomas <thomas.schneider@datadoghq.com>

Author: pront

Cargo.toml

@@ -12,7 +12,7 @@ default-run = "vector"
 autobenches = false # our benchmarks are not runnable on their own either way
 # Minimum supported rust version
 # See docs/DEVELOPING.md for policy
-rust-version = "1.92"
+rust-version = "1.95"
 
 [[bin]]
 name = "vector"
@@ -47,8 +47,8 @@ lto = "fat"
 [profile.bench]
 debug = true
 
-[lints.rust]
-unexpected_cfgs = { level = "warn", check-cfg = ['cfg(tokio_unstable)'] }
+[lints]
+workspace = true
 
 [package.metadata.deb]
 name = "vector"
@@ -136,6 +136,15 @@ members = [
   "vdev",
 ]
 
+[workspace.lints.rust]
+# 'cfg(tokio_unstable)' used in vector; 'cfg(ddsketch_extended)' used in vector-core
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(tokio_unstable)', 'cfg(ddsketch_extended)'] }
+
+[workspace.lints.clippy]
+string_slice = "warn"
+await_holding_lock = "warn"
+let_underscore_must_use = "warn"
+
 [workspace.dependencies]
 antithesis-instrumentation = { version = "0.1", default-features = false, features = [] }
 antithesis_sdk = { version = "0.2", default-features = false, features = [] }

lib/codecs/Cargo.toml

@@ -5,8 +5,8 @@ authors = ["Vector Contributors <vector@datadoghq.com>"]
 edition = "2024"
 publish = false
 
-[lints.clippy]
-unwrap-used = "deny"
+[lints]
+workspace = true
 
 [[bin]]
 name = "generate-avro-fixtures"

lib/codecs/src/encoding/format/parquet.rs

@@ -1,3 +1,6 @@
+// Derivative's Debug impl generates 'let _ = field.fmt(f)' which triggers this lint.
+#![allow(clippy::let_underscore_must_use)]
+
 //! Parquet batch format codec for batched event encoding
 //!
 //! Provides Apache Parquet format encoding with schema file support and auto-inference.

lib/codecs/src/encoding/format/syslog.rs

@@ -4,7 +4,6 @@ use lookup::lookup_v2::ConfigTargetPath;
 use serde_json;
 use std::borrow::Cow;
 use std::collections::BTreeMap;
-use std::fmt::Write;
 use std::str::FromStr;
 use strum::{EnumString, FromRepr, VariantNames};
 use tokio_util::codec::Encoder;
@@ -235,8 +234,9 @@ where
         None => Cow::Borrowed(s), // All valid, zero allocation
         Some((first_invalid_idx, _)) => {
             let mut result = String::with_capacity(s.len());
-            result.push_str(&s[..first_invalid_idx]); // Copy valid prefix
-            for c in s[first_invalid_idx..].chars() {
+            let (valid_prefix, remainder) = s.split_at(first_invalid_idx);
+            result.push_str(valid_prefix);
+            for c in remainder.chars() {
                 result.push(if is_valid(c) { c } else { '_' });
             }
 
@@ -320,7 +320,7 @@ impl SyslogMessage {
     fn encode(&self, rfc: &SyslogRFC) -> String {
         let mut result = String::with_capacity(256);
 
-        let _ = write!(result, "{}", self.pri.encode());
+        result.push_str(&self.pri.encode().to_string());
 
         if *rfc == SyslogRFC::Rfc5424 {
             result.push_str(SYSLOG_V1);
@@ -329,7 +329,7 @@ impl SyslogMessage {
 
         match rfc {
             SyslogRFC::Rfc3164 => {
-                let _ = write!(result, "{} ", self.timestamp.format("%b %e %H:%M:%S"));
+                result.push_str(&format!("{} ", self.timestamp.format("%b %e %H:%M:%S")));
             }
             SyslogRFC::Rfc5424 => {
                 result.push_str(
@@ -435,12 +435,12 @@ impl StructuredData {
             self.elements
                 .iter()
                 .fold(String::new(), |mut acc, (sd_id, sd_params)| {
-                    let _ = write!(acc, "[{sd_id}");
+                    acc.push_str(&format!("[{sd_id}"));
                     for (key, value) in sd_params {
                         let esc_val = escape_sd_value(value);
-                        let _ = write!(acc, " {key}=\"{esc_val}\"");
+                        acc.push_str(&format!(" {key}=\"{esc_val}\""));
                     }
-                    let _ = write!(acc, "]");
+                    acc.push(']');
                     acc
                 })
         }

lib/codecs/src/lib.rs

@@ -3,6 +3,7 @@
 
 #![deny(missing_docs)]
 #![deny(warnings)]
+#![deny(clippy::unwrap_used)]
 
 mod common;
 mod decoder_framed_read;

lib/dnsmsg-parser/Cargo.toml

@@ -6,8 +6,8 @@ edition = "2024"
 publish = false
 license = "MIT"
 
-[lints.clippy]
-unwrap-used = "forbid"
+[lints]
+workspace = true
 
 [dependencies]
 data-encoding = "2.10"

lib/dnsmsg-parser/src/lib.rs

@@ -1,4 +1,5 @@
 #![deny(warnings)]
+#![deny(clippy::unwrap_used)]
 #![warn(
     missing_debug_implementations,
     rust_2018_idioms,

lib/docs-renderer/Cargo.toml

@@ -5,6 +5,9 @@ authors = ["Vector Contributors <vector@datadoghq.com>"]
 edition = "2024"
 publish = false
 
+[lints]
+workspace = true
+
 [dependencies]
 anyhow.workspace = true
 serde.workspace = true

lib/fakedata/Cargo.toml

@@ -6,6 +6,9 @@ edition = "2024"
 publish = false
 license = "MPL-2.0"
 
+[lints]
+workspace = true
+
 [dependencies]
 chrono.workspace = true
 rand.workspace = true

lib/file-source-common/Cargo.toml

@@ -6,6 +6,9 @@ edition = "2024"
 publish = false
 license = "MIT"
 
+[lints]
+workspace = true
+
 [target.'cfg(windows)'.dependencies]
 libc.workspace = true
 winapi = { version = "0.3", features = ["winioctl"] }