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

Cargo.toml

@@ -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

@@ -7,6 +7,9 @@ publish = false
 
 [lints.clippy]
 unwrap-used = "deny"
+string_slice = "warn"
+await_holding_lock = "warn"
+let_underscore_must_use = "warn"
 
 [[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

@@ -235,8 +235,9 @@ 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 +321,7 @@ impl SyslogMessage {
     fn encode(&self, rfc: &SyslogRFC) -> String {
         let mut result = String::with_capacity(256);
 
-        let _ = write!(result, "{}", self.pri.encode());
+        write!(result, "{}", self.pri.encode()).ok();
 
         if *rfc == SyslogRFC::Rfc5424 {
             result.push_str(SYSLOG_V1);
@@ -329,7 +330,7 @@ impl SyslogMessage {
 
         match rfc {
             SyslogRFC::Rfc3164 => {
-                let _ = write!(result, "{} ", self.timestamp.format("%b %e %H:%M:%S"));
+                write!(result, "{} ", self.timestamp.format("%b %e %H:%M:%S")).ok();
             }
             SyslogRFC::Rfc5424 => {
                 result.push_str(
@@ -435,12 +436,12 @@ impl StructuredData {
             self.elements
                 .iter()
                 .fold(String::new(), |mut acc, (sd_id, sd_params)| {
-                    let _ = write!(acc, "[{sd_id}");
+                    write!(acc, "[{sd_id}").ok();
                     for (key, value) in sd_params {
                         let esc_val = escape_sd_value(value);
-                        let _ = write!(acc, " {key}=\"{esc_val}\"");
+                        write!(acc, " {key}=\"{esc_val}\"").ok();
                     }
-                    let _ = write!(acc, "]");
+                    write!(acc, "]").ok();
                     acc
                 })
         }

lib/dnsmsg-parser/Cargo.toml

@@ -8,6 +8,9 @@ license = "MIT"
 
 [lints.clippy]
 unwrap-used = "forbid"
+string_slice = "warn"
+await_holding_lock = "warn"
+let_underscore_must_use = "warn"
 
 [dependencies]
 data-encoding = "2.10"

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"] }

lib/file-source/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"] }

lib/k8s-e2e-tests/Cargo.toml

@@ -7,6 +7,9 @@ description = "End-to-end tests of Vector in the Kubernetes environment"
 publish = false
 license = "MPL-2.0"
 
+[lints]
+workspace = true
+
 [dependencies]
 futures.workspace = true
 k8s-openapi = { version = "0.27.0", default-features = false, features = ["v1_31"] }

lib/k8s-test-framework/Cargo.toml

@@ -7,6 +7,9 @@ description = "Kubernetes Test Framework used to test Vector in Kubernetes"
 publish = false
 license = "MPL-2.0"
 
+[lints]
+workspace = true
+
 [dependencies]
 k8s-openapi = { version = "0.27.0", default-features = false, features = ["v1_31"] }
 serde_json.workspace = true

lib/loki-logproto/Cargo.toml

@@ -7,6 +7,9 @@ publish = false
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[lints]
+workspace = true
+
 [dependencies]
 prost.workspace = true
 prost-types.workspace = true

lib/opentelemetry-proto/Cargo.toml

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

lib/prometheus-parser/Cargo.toml

@@ -8,6 +8,9 @@ license = "MPL-2.0"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[lints]
+workspace = true
+
 [dependencies]
 indexmap.workspace = true
 nom.workspace = true

lib/prometheus-parser/src/lib.rs

@@ -157,6 +157,10 @@ impl GroupKind {
         prefix_len: usize,
         metric: Metric,
     ) -> Result<Option<Metric>, ParserError> {
+        #[expect(
+            clippy::string_slice,
+            reason = "prefix_len is always self.name.len(), a valid UTF-8 boundary"
+        )]
         let suffix = &metric.name[prefix_len..];
         let mut key = GroupKey {
             timestamp: metric.timestamp,
@@ -328,15 +332,23 @@ struct MetricGroupSet(IndexMap<String, GroupKind>);
 
 impl MetricGroupSet {
     fn get_group<'a>(&'a mut self, name: &str) -> (usize, &'a String, &'a mut GroupKind) {
-        let len = name.len();
         let name = if self.0.contains_key(name) {
             name
-        } else if name.ends_with("_bucket") && self.0.contains_key(&name[..len - 7]) {
-            &name[..len - 7]
-        } else if name.ends_with("_sum") && self.0.contains_key(&name[..len - 4]) {
-            &name[..len - 4]
-        } else if name.ends_with("_count") && self.0.contains_key(&name[..len - 6]) {
-            &name[..len - 6]
+        } else if let Some(base) = name
+            .strip_suffix("_bucket")
+            .filter(|b| self.0.contains_key(*b))
+        {
+            base
+        } else if let Some(base) = name
+            .strip_suffix("_sum")
+            .filter(|b| self.0.contains_key(*b))
+        {
+            base
+        } else if let Some(base) = name
+            .strip_suffix("_count")
+            .filter(|b| self.0.contains_key(*b))
+        {
+            base
         } else {
             self.0
                 .insert(name.into(), GroupKind::new(MetricKind::Untyped));

lib/tracing-limit/Cargo.toml

@@ -8,6 +8,9 @@ license = "MPL-2.0"
 
 [lints.clippy]
 unwrap-used = "forbid"
+string_slice = "warn"
+await_holding_lock = "warn"
+let_underscore_must_use = "warn"
 
 [dependencies]
 tracing-core = { version = "0.1", default-features = false }

lib/vector-api-client/Cargo.toml

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

lib/vector-buffers/Cargo.toml

@@ -5,8 +5,8 @@ authors = ["Vector Contributors <vector@datadoghq.com>"]
 edition = "2024"
 publish = false
 
-[lints.rust]
-unexpected_cfgs = { level = "warn", check-cfg = ['cfg(tokio_unstable)'] }
+[lints]
+workspace = true
 
 [dependencies]
 async-recursion = "1.1.1"

lib/vector-buffers/src/topology/channel/sender.rs

@@ -1,3 +1,6 @@
+// Derivative's Debug impl generates 'let _ = field.fmt(f)' which triggers this lint.
+#![allow(clippy::let_underscore_must_use)]
+
 use std::{sync::Arc, time::Instant};
 
 use async_recursion::async_recursion;

lib/vector-common-macros/Cargo.toml

@@ -4,6 +4,9 @@ version = "0.1.0"
 edition = "2024"
 license = "MPL-2.0"
 
+[lints]
+workspace = true
+
 [lib]
 proc-macro = true
 

lib/vector-common/Cargo.toml

@@ -6,6 +6,9 @@ edition = "2024"
 publish = false
 license = "MPL-2.0"
 
+[lints]
+workspace = true
+
 [features]
 default = [
   "btreemap",

lib/vector-common/src/event_test_util.rs

@@ -73,9 +73,9 @@ pub fn record_internal_event(event: &str) {
     // Remove leading '&'
     let event = event.strip_prefix('&').unwrap_or(event);
     // Remove trailing '{fields…}'
-    let event = event.find('{').map_or(event, |par| &event[..par]);
+    let event = event.split_once('{').map_or(event, |(before, _)| before);
     // Remove trailing '::from…'
-    let event = event.find(':').map_or(event, |colon| &event[..colon]);
+    let event = event.split_once(':').map_or(event, |(before, _)| before);
 
     EVENTS_RECORDED.with(|er| er.borrow_mut().insert(event.trim().into()));
 }

lib/vector-config-common/Cargo.toml

@@ -4,6 +4,9 @@ version = "0.1.0"
 edition = "2024"
 license = "MPL-2.0"
 
+[lints]
+workspace = true
+
 [dependencies]
 convert_case.workspace = true
 darling.workspace = true

lib/vector-config-common/src/schema/generator.rs

@@ -117,12 +117,9 @@ impl SchemaGenerator {
                 ..
             }) => {
                 let definitions_path = &self.settings().definitions_path;
-                if schema_ref.starts_with(definitions_path) {
-                    let name = &schema_ref[definitions_path.len()..];
-                    self.definitions.get(name)
-                } else {
-                    None
-                }
+                schema_ref
+                    .strip_prefix(definitions_path.as_str())
+                    .and_then(|name| self.definitions.get(name))
             }
             _ => None,
         }

lib/vector-config-macros/Cargo.toml

@@ -4,6 +4,9 @@ version = "0.1.0"
 edition = "2024"
 license = "MPL-2.0"
 
+[lints]
+workspace = true
+
 [lib]
 proc-macro = true
 

lib/vector-config/Cargo.toml

@@ -6,6 +6,9 @@ edition = "2024"
 publish = false
 license = "MPL-2.0"
 
+[lints]
+workspace = true
+
 [[test]]
 name = "integration"
 path = "tests/integration/lib.rs"

lib/vector-config/tests/integration/smoke.rs

@@ -288,7 +288,9 @@ impl TryFrom<String> for SocketListenAddr {
             Err(_) => {
                 let fd: usize = match input.as_str() {
                     "systemd" => Ok(0),
-                    s if s.starts_with("systemd#") => s[8..]
+                    s if s.starts_with("systemd#") => s
+                        .strip_prefix("systemd#")
+                        .unwrap()
                         .parse::<usize>()
                         .map_err(|_| "failed to parse usize".to_string())?
                         .checked_sub(1)

lib/vector-core/Cargo.toml

@@ -5,8 +5,8 @@ authors = ["Vector Contributors <vector@datadoghq.com>"]
 edition = "2024"
 publish = false
 
-[lints.rust]
-unexpected_cfgs = { level = "warn", check-cfg = ['cfg(ddsketch_extended)'] }
+[lints]
+workspace = true
 
 [dependencies]
 async-trait.workspace = true

lib/vector-core/src/event/util/log/all_fields.rs

@@ -259,7 +259,11 @@ mod test {
         .map(|(k, v)| (k.into(), v))
         .collect();
         // Compare without the leading `"` char so that the order is the same as the collected fields.
-        expected.sort_by(|(a, _), (b, _)| a[1..].cmp(&b[1..]));
+        expected.sort_by(|(a, _), (b, _)| {
+            a.strip_prefix('"')
+                .unwrap_or(a)
+                .cmp(b.strip_prefix('"').unwrap_or(b))
+        });
 
         assert_eq!(collected, expected);
     }

lib/vector-core/src/event/vrl_target.rs

@@ -303,7 +303,7 @@ impl Target for VrlTarget {
                                 metric.remove_tags();
                                 for (field, value) in &value {
                                     set_metric_tag_values(
-                                        field[..].into(),
+                                        field.as_str().into(),
                                         value,
                                         metric,
                                         *multi_value_tags,