feat(dylint): exempt test files from telemetry semconv lints (#453)

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>

Author: yordis

rsworkspace/crates/acp-nats/src/agent/test_support/tests.rs

@@ -50,7 +50,6 @@ fn has_request_metric_returns_false_when_empty() {
 // Builds a histogram under a counter's name to prove the lookup rejects the
 // wrong instrument kind; that mismatch is the point, so the generated
 // `build_acp_requests` (a counter) cannot stand in here.
-#[cfg_attr(dylint_lib = "trogon_lints", allow(telemetry_metric_construction))]
 fn has_request_metric_returns_false_for_histogram_metric() {
     let (provider, exporter) = test_provider();
     let meter = provider.meter("test");
@@ -105,7 +104,6 @@ fn has_error_metric_rejects_wrong_reason() {
 // Builds a histogram under a counter's name to prove the lookup rejects the
 // wrong instrument kind; that mismatch is the point, so the generated
 // `build_acp_errors` (a counter) cannot stand in here.
-#[cfg_attr(dylint_lib = "trogon_lints", allow(telemetry_metric_construction))]
 fn has_error_metric_returns_false_for_histogram_metric() {
     let (provider, exporter) = test_provider();
     let meter = provider.meter("test");

rsworkspace/crates/trogon-telemetry/src/log/tests.rs

@@ -44,7 +44,6 @@ fn platform_log_dir_returns_path_ending_with_service_name() {
 #[test]
 // Exercises the export pipeline with a throwaway resource attribute that has no
 // semantic-convention counterpart.
-#[cfg_attr(dylint_lib = "trogon_lints", allow(telemetry_key_value_literal))]
 fn init_provider_lifecycle() {
     let resource = opentelemetry_sdk::Resource::builder()
         .with_service_name("test-log")

rsworkspace/crates/trogon-telemetry/src/metric/tests.rs

@@ -5,7 +5,6 @@ use opentelemetry_sdk::Resource;
 #[test]
 // Exercises the export pipeline with a throwaway resource attribute that has no
 // semantic-convention counterpart.
-#[cfg_attr(dylint_lib = "trogon_lints", allow(telemetry_key_value_literal))]
 fn init_provider_returns_valid_provider() {
     let resource = Resource::builder()
         .with_service_name("test-metric")

rsworkspace/crates/trogon-telemetry/src/trace/tests.rs

@@ -5,7 +5,6 @@ use opentelemetry_sdk::Resource;
 #[test]
 // Exercises the export pipeline with a throwaway resource attribute that has no
 // semantic-convention counterpart.
-#[cfg_attr(dylint_lib = "trogon_lints", allow(telemetry_key_value_literal))]
 fn init_provider_returns_valid_provider() {
     let resource = Resource::builder()
         .with_service_name("test-trace")

rsworkspace/dylints/trogon_lints/examples/telemetry_key_value_literal_tests.rs

@@ -0,0 +1,14 @@
+//! UI fixture proving `telemetry_key_value_literal` is suppressed in test files.
+//! The example is named `*_tests.rs`, so the same inline `KeyValue::new` string
+//! key that fires in `telemetry_key_value_literal.rs` produces no diagnostic
+//! here. Absent a `.stderr`, the harness asserts zero diagnostics.
+
+use opentelemetry::KeyValue;
+
+fn inline_key() -> KeyValue {
+    KeyValue::new("messaging.system", "nats")
+}
+
+fn main() {
+    let _ = inline_key();
+}

rsworkspace/dylints/trogon_lints/examples/telemetry_metric_construction_tests.rs

@@ -0,0 +1,20 @@
+//! UI fixture proving `telemetry_metric_construction` is suppressed in test
+//! files. The example is named `*_tests.rs`, so opening an instrument builder
+//! inline, which is denied in `telemetry_metric_construction.rs`, produces no
+//! diagnostic here. Absent a `.stderr`, the harness asserts zero diagnostics.
+
+use opentelemetry::metrics::{Counter, Meter};
+
+const ACP_REQUESTS: &str = "acp.requests";
+
+fn inline_build(meter: &Meter) -> Counter<u64> {
+    meter
+        .u64_counter(ACP_REQUESTS)
+        .with_description("Total number of ACP requests")
+        .build()
+}
+
+fn main() {
+    let meter = opentelemetry::global::meter("fixture");
+    let _ = inline_build(&meter);
+}

rsworkspace/dylints/trogon_lints/src/telemetry_key_value_literal.rs

@@ -5,7 +5,7 @@ use rustc_lint::LateContext;
 use rustc_middle::ty;
 
 use crate::TELEMETRY_KEY_VALUE_LITERAL;
-use crate::telemetry_literal::string_literal_span;
+use crate::telemetry_literal::{in_test_file, string_literal_span};
 
 #[derive(Default)]
 pub(crate) struct TelemetryKeyValueLiteral;
@@ -24,6 +24,9 @@ impl TelemetryKeyValueLiteral {
         if !callee_is_key_value_new(cx, callee) {
             return;
         }
+        if in_test_file(cx, key_span) {
+            return;
+        }
 
         span_lint_and_then(
             cx,

rsworkspace/dylints/trogon_lints/src/telemetry_literal.rs

@@ -2,6 +2,7 @@ use rustc_ast::LitKind;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty;
+use rustc_span::{FileName, Span};
 
 /// Every `opentelemetry` `Meter` method that opens an instrument builder, keyed
 /// by the instrument name as its first argument. Shared by the metric lints.
@@ -34,6 +35,24 @@ pub(crate) fn string_literal_span(expr: &Expr<'_>) -> Option<rustc_span::Span> {
     }
 }
 
+/// Whether `span` originates in a test file, i.e. one whose stem is `tests` or
+/// ends in `_tests` (`tests.rs`, `parse_tests.rs`). Telemetry call sites in
+/// tests exercise the instruments directly rather than routing through the
+/// generated `trogon_semconv` constants, so the semconv lints exempt them.
+pub(crate) fn in_test_file(cx: &LateContext<'_>, span: Span) -> bool {
+    let file = cx.tcx.sess.source_map().lookup_char_pos(span.lo()).file;
+    let FileName::Real(real) = &file.name else {
+        return false;
+    };
+    let Some(stem) = real
+        .local_path()
+        .and_then(|path| path.file_stem()?.to_str().map(str::to_owned))
+    else {
+        return false;
+    };
+    stem == "tests" || stem.ends_with("_tests")
+}
+
 /// Whether the adjusted type of `receiver`, with references peeled, is the ADT
 /// `krate::...::ty_name`. Telemetry types are identified by their owning crate
 /// and name rather than a full def-path, mirroring how the checked crates avoid

rsworkspace/dylints/trogon_lints/src/telemetry_metric_construction.rs

@@ -4,7 +4,7 @@ use rustc_hir::{Expr, ExprKind};
 use rustc_lint::LateContext;
 
 use crate::TELEMETRY_METRIC_CONSTRUCTION;
-use crate::telemetry_literal::{INSTRUMENT_BUILDERS, receiver_is_type};
+use crate::telemetry_literal::{INSTRUMENT_BUILDERS, in_test_file, receiver_is_type};
 
 #[derive(Default)]
 pub(crate) struct TelemetryMetricConstruction;
@@ -27,6 +27,9 @@ impl TelemetryMetricConstruction {
         if !receiver_is_type(cx, receiver, "opentelemetry", "Meter") {
             return;
         }
+        if in_test_file(cx, expr.span) {
+            return;
+        }
 
         span_lint_and_then(
             cx,