Move contract annotations into one datadog.contract package

.agents/skills/perf-review/references/checks.md

@@ -25,8 +25,8 @@ Format: **pattern** — *expensive when (the interprocedural condition to trace)
 5. **Polymorphic dispatch on a hot path** — *a hot call site becomes polymorphic enough to defeat the runtime's inlining/devirtualization (real for JIT runtimes — JVM/.NET/V8; AOT/interpreted differ)* — **flag-as-measure** ("may defeat devirtualization; verify on the target runtime") — SEV-2/3 — fix: keep hot call sites mono/bi-morphic; specialize.
 6. **FFI / native-boundary crossing on a hot path** *(central to the shared-core effort)* — *a native crossing per-span/per-item (not batched), or transporting strings/objects rather than primitives/IDs* — flag-with-confidence (boundary cost is mechanism-determined; runtime-specific pinning → addendum) — SEV-1/2 (SEV-1 if it blocks/pins under concurrency) — fix: batch (one per flush, not per item); transport interned IDs not strings; keep crossings off the hot/concurrency path.
 7. **Escape / allocation-elision defeated** *(Java/Go/.NET/V8 all have a version)* — *a refactor makes a previously-local object escape (stored, returned, captured by a closure, passed to a virtual/non-inlined call) → silent heap allocation on a hot path* — **flag-as-measure** ("may now escape and allocate; verify with an allocation profiler") — SEV-2/3 — fix: keep it local; avoid the escaping store/capture.
-8. **`@NoEscape` field-storage violation** — *a field (instance or static, directly or as a generic type argument) declared with an `@NoEscape`-annotated type (`datadog.trace.api.function.NoEscape`), **or** initialized directly from a call to an `@NoEscape`-annotated method — with no comment at the declaration justifying the retention*. The type form marks a concrete type (e.g. `SubSequence`); the method form exists for a return value whose concrete type can't itself carry the annotation (an anonymous class or lambda implementing a JDK interface). The annotation's own javadoc carries a self-contained "Checker contract" section (trigger / not-a-trigger / violation example / compliant example, both forms) written so this can be checked from the diff alone, with no other context needed. The underlying rule is "should", not "must" (RFC-2119 sense): a trigger is a presumptive finding, not an automatic failure — compliant if the declaration carries either a `// Retained on purpose: <reason>`-style comment, or `@SuppressPerfContract(value = NoEscape.class, reason = "...")` (`datadog.perfcontract.SuppressPerfContract` — the generic exemption mechanism shared by every perf-contract marker, not `@NoEscape`-specific), or a named canned-exception annotation itself meta-annotated `@SuppressPerfContract` with `NoEscape.class` among its `value` (e.g. a hypothetical `@Borrowed`) — treat the meta-annotation's own `reason` as satisfying the requirement. Don't flag a `SuppressPerfContract`/canned-exception use as non-compliant just for being terse; that mirrors the annotation's own Checker contract. **flag-with-confidence** — SEV-2/3 (SEV-1 if the annotated type/method shares backing storage with something large, per its own javadoc). Current wearers: `SubSequence`, `Maybe` (type form; see J7 below for `SubSequence`'s specific retention-vs-transient discriminator). **No lint enforces this yet — the AI reviewer is the only check, so this stays here (not under deterministic-lint candidates below) until a checker lands and it can migrate down.**
-9. **`@StaticLifetime` field-lifetime violation** — *a field annotated `@StaticLifetime` (`datadog.perfcontract.StaticLifetime`), **or** an unannotated field whose declared type is listed in the contract's `@ImpliedFor` (`datadog.perfcontract.ImpliedFor`; read the types from the `@ImpliedFor` on `StaticLifetime` itself, subtypes included), that is neither `static final` nor a `final` instance field declared on a class annotated `@Singleton` (`datadog.perfcontract.Singleton`)*. Declaration-scan only, same shape as the `@NoEscape` field-storage check above — it does not attempt to prove a field is actually reused enough to be worth caching, and it does not catch an unannotated per-instance cache of a non-implied type; it only guards fields that opt in or whose type implies the contract. A deliberate per-instance holder of an implied type is compliant with `@SuppressPerfContract(value = StaticLifetime.class, reason = "...")`. `@Singleton`, applied to a class, is a trusted, unverified declaration (v1 posture — the same stance the other perf-contract markers take toward `static final` itself) that the class has exactly one process-wide instance; declaring it satisfies `@StaticLifetime` for that class's `final` instance fields. **flag-with-confidence** — SEV-2/3, motivated by a real production defect (a per-request-constructed cache that never actually amortized anything — see the annotation's own javadoc for the full trigger/accepted-form table). Refines the "per-call cache / expensive-object creation that should be static/once" deterministic-lint candidate below by giving that pattern's opted-in subset an explicit annotation and trigger; the unannotated general case is still that line's job. **No lint enforces this yet — the AI reviewer is the only check, so this stays here (not under deterministic-lint candidates below) until a checker lands and it can migrate down.**
+8. **`@NoEscape` field-storage violation** — *a field (instance or static, directly or as a generic type argument) declared with an `@NoEscape`-annotated type (`datadog.trace.api.function.NoEscape`), **or** initialized directly from a call to an `@NoEscape`-annotated method — with no comment at the declaration justifying the retention*. The type form marks a concrete type (e.g. `SubSequence`); the method form exists for a return value whose concrete type can't itself carry the annotation (an anonymous class or lambda implementing a JDK interface). The annotation's own javadoc carries a self-contained "Checker contract" section (trigger / not-a-trigger / violation example / compliant example, both forms) written so this can be checked from the diff alone, with no other context needed. The underlying rule is "should", not "must" (RFC-2119 sense): a trigger is a presumptive finding, not an automatic failure — compliant if the declaration carries either a `// Retained on purpose: <reason>`-style comment, or `@SuppressPerfContract(value = NoEscape.class, reason = "...")` (`datadog.contract.SuppressPerfContract` — the generic exemption mechanism shared by every perf-contract marker, not `@NoEscape`-specific), or a named canned-exception annotation itself meta-annotated `@SuppressPerfContract` with `NoEscape.class` among its `value` (e.g. a hypothetical `@Borrowed`) — treat the meta-annotation's own `reason` as satisfying the requirement. Don't flag a `SuppressPerfContract`/canned-exception use as non-compliant just for being terse; that mirrors the annotation's own Checker contract. **flag-with-confidence** — SEV-2/3 (SEV-1 if the annotated type/method shares backing storage with something large, per its own javadoc). Current wearers: `SubSequence`, `Maybe` (type form; see J7 below for `SubSequence`'s specific retention-vs-transient discriminator). **No lint enforces this yet — the AI reviewer is the only check, so this stays here (not under deterministic-lint candidates below) until a checker lands and it can migrate down.**
+9. **`@StaticLifetime` field-lifetime violation** — *a field annotated `@StaticLifetime` (`datadog.contract.StaticLifetime`), **or** an unannotated field whose declared type is listed in the contract's `@ImpliedFor` (`datadog.contract.ImpliedFor`; read the types from the `@ImpliedFor` on `StaticLifetime` itself, subtypes included), that is neither `static final` nor a `final` instance field declared on a class annotated `@Singleton` (`datadog.contract.Singleton`)*. Declaration-scan only, same shape as the `@NoEscape` field-storage check above — it does not attempt to prove a field is actually reused enough to be worth caching, and it does not catch an unannotated per-instance cache of a non-implied type; it only guards fields that opt in or whose type implies the contract. A deliberate per-instance holder of an implied type is compliant with `@SuppressPerfContract(value = StaticLifetime.class, reason = "...")`. `@Singleton`, applied to a class, is a trusted, unverified declaration (v1 posture — the same stance the other perf-contract markers take toward `static final` itself) that the class has exactly one process-wide instance; declaring it satisfies `@StaticLifetime` for that class's `final` instance fields. **flag-with-confidence** — SEV-2/3, motivated by a real production defect (a per-request-constructed cache that never actually amortized anything — see the annotation's own javadoc for the full trigger/accepted-form table). Refines the "per-call cache / expensive-object creation that should be static/once" deterministic-lint candidate below by giving that pattern's opted-in subset an explicit annotation and trigger; the unannotated general case is still that line's job. **No lint enforces this yet — the AI reviewer is the only check, so this stays here (not under deterministic-lint candidates below) until a checker lands and it can migrate down.**
 
 ## Deterministic-lint candidates (DON'T spend AI budget — make these real lints)
 Fixed-signature, mechanically checkable:

.github/CODEOWNERS

@@ -88,8 +88,7 @@
 /internal-api/src/*/*/datadog/trace/api/endpoint/      @DataDog/apm-java
 /internal-api/src/*/*/datadog/trace/api/env/           @DataDog/apm-java
 /internal-api/src/*/*/datadog/trace/api/function/      @DataDog/apm-java
-/internal-api/src/*/*/datadog/apicontract/             @DataDog/apm-java
-/internal-api/src/*/*/datadog/perfcontract/            @DataDog/apm-java
+/internal-api/src/*/*/datadog/contract/                @DataDog/apm-java
 /internal-api/src/*/*/datadog/trace/api/intake/        @DataDog/apm-java
 /internal-api/src/*/*/datadog/trace/api/logging/       @DataDog/apm-java
 /internal-api/src/*/*/datadog/trace/api/metrics/       @DataDog/apm-java

communication/src/main/java/datadog/communication/serialization/msgpack/MsgPackWriter.java

@@ -8,8 +8,8 @@
 import datadog.communication.serialization.StreamingBuffer;
 import datadog.communication.serialization.ValueWriter;
 import datadog.communication.serialization.WritableFormatter;
-import datadog.perfcontract.StaticLifetime;
-import datadog.perfcontract.SuppressPerfContract;
+import datadog.contract.StaticLifetime;
+import datadog.contract.SuppressPerfContract;
 import datadog.trace.bootstrap.instrumentation.api.UTF8BytesString;
 import java.nio.BufferOverflowException;
 import java.nio.ByteBuffer;

gradle/forbiddenApiFilters/instrumentation.txt

@@ -4,6 +4,6 @@
 datadog.trace.bootstrap.instrumentation.api.AgentSpan#setServiceName(java.lang.String)
 
 # TagMap.internals() skips checks the tracer core has already made; it is @Restricted to the core
-# (see datadog.apicontract.Restricted). Instrumentation uses TagMap's checked methods.
+# (see datadog.contract.Restricted). Instrumentation uses TagMap's checked methods.
 @defaultMessage TagMap.internals() is restricted to the tracer core; use TagMap's checked methods instead.
 datadog.trace.api.TagMap#internals()

internal-api/src/main/java/datadog/perfcontract/ImpliedFor.java → internal-api/src/main/java/datadog/contract/ImpliedFor.java

@@ -1,4 +1,4 @@
-package datadog.perfcontract;
+package datadog.contract;
 
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;

internal-api/src/main/java/datadog/perfcontract/PerfContract.java → internal-api/src/main/java/datadog/contract/PerfContract.java

@@ -1,4 +1,4 @@
-package datadog.perfcontract;
+package datadog.contract;
 
 import datadog.trace.api.function.NoEscape;
 import java.lang.annotation.Documented;

internal-api/src/main/java/datadog/apicontract/Restricted.java → internal-api/src/main/java/datadog/contract/Restricted.java

@@ -1,4 +1,4 @@
-package datadog.apicontract;
+package datadog.contract;
 
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;

internal-api/src/main/java/datadog/perfcontract/Singleton.java → internal-api/src/main/java/datadog/contract/Singleton.java

@@ -1,4 +1,4 @@
-package datadog.perfcontract;
+package datadog.contract;
 
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;

internal-api/src/main/java/datadog/perfcontract/StaticLifetime.java → internal-api/src/main/java/datadog/contract/StaticLifetime.java

@@ -1,4 +1,4 @@
-package datadog.perfcontract;
+package datadog.contract;
 
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;

internal-api/src/main/java/datadog/perfcontract/SuppressPerfContract.java → internal-api/src/main/java/datadog/contract/SuppressPerfContract.java

@@ -1,4 +1,4 @@
-package datadog.perfcontract;
+package datadog.contract;
 
 import java.lang.annotation.Annotation;
 import java.lang.annotation.Documented;

internal-api/src/main/java/datadog/trace/api/TagMap.java

@@ -1,6 +1,6 @@
 package datadog.trace.api;
 
-import datadog.apicontract.Restricted;
+import datadog.contract.Restricted;
 import datadog.trace.api.function.NoEscape;
 import datadog.trace.api.function.TriConsumer;
 import datadog.trace.api.internal.VisibleForTesting;

internal-api/src/main/java/datadog/trace/api/function/NoEscape.java

@@ -1,7 +1,7 @@
 package datadog.trace.api.function;
 
-import datadog.perfcontract.PerfContract;
-import datadog.perfcontract.SuppressPerfContract;
+import datadog.contract.PerfContract;
+import datadog.contract.SuppressPerfContract;
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;

internal-api/src/main/java/datadog/trace/api/function/Strategy.java

@@ -1,6 +1,6 @@
 package datadog.trace.api.function;
 
-import datadog.perfcontract.PerfContract;
+import datadog.contract.PerfContract;
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Inherited;

internal-api/src/main/java/datadog/trace/api/function/StrategyConsumer.java

@@ -1,6 +1,6 @@
 package datadog.trace.api.function;
 
-import datadog.perfcontract.PerfContract;
+import datadog.contract.PerfContract;
 import java.lang.annotation.Documented;
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Retention;