chore(ci): Prepare 1.2.3 (#2037)

## Summary

Release-prep PR for **ADP 1.2.3** on `releases/1.2.x`. Bumps the version and bundles four fixes. Because 1.2.x is on Rust 1.96.0 (same as `main`), the `fetch_update` fix could be cherry-picked directly rather than needing the `#[allow(deprecated)]` workaround used on 1.1.0.

1. **Honor `site` when `dd_url` equals the default-derived URL** — corresponds to #2028 (`7ec65f2`). The Core Agent's config stream sends `dd_url` at its schema default (`https://app.datadoghq.com`) for every configuration, even when the operator only set `site`, so ADP routed all traffic to the US1 intake and `site` was effectively ignored (#1965). A `dd_url` equal to the default-derived URL is now filtered to `None` at deserialization, letting `site` determine the endpoint. `set_dd_url` bypasses serde and is unaffected. Adapted to the 1.2.x code (no `configured_primary_endpoint`), so the change is confined to the `dd_url` deserializer plus tests.

2. **Unblock the nightly `generate-api-docs` build** — cherry-pick of #2007 (`917e05f`). Newer nightly toolchains deprecate `Atomic*::fetch_update`; under `#![deny(warnings)]`, `cargo +nightly doc` turns that into a hard error. Since 1.2.x uses the 1.96.0 toolchain (where `try_update` is stable), the three call sites switch to `try_update`, matching `main`. (The `fixed_size.rs` hunk from the original commit was dropped — that method doesn't exist on 1.2.x and has no `fetch_update` to fix.)

3. **Update `anyhow`** — cherry-pick of #1945 (`bc51393`). Bumps `anyhow` 1.0.102 → 1.0.103 in `Cargo.lock` to unblock `check deny`. (The `2a7be76` hash is the gh-pages docs artifact for that PR; `bc51393` is the source commit.)

4. **Bump `crossbeam-epoch` to 0.9.20** — fresh fix for RUSTSEC-2026-0204. `crossbeam-epoch 0.9.18` (an invalid pointer dereference in the `fmt::Pointer` impl for `Atomic`/`Shared`) fails `check-deny`. This is a repo-wide issue; the equivalent fix for `main` is #2038. Applied directly here (semver-compatible, lockfile-only bump) rather than cherry-picked, since it landed on the release branches in parallel with the main PR.

Plus a `chore(dev): Bump ADP to 1.2.3` commit updating `bin/agent-data-plane/Cargo.toml` and the lockfile.

## Test plan

- New unit tests for the `dd_url`/`site` resolution (default filtered → `None`; explicit override wins; `set_dd_url` never filtered; end-to-end `build_primary_endpoint` for both cases).
- `make check-deny` passes with the crossbeam-epoch bump.
- `cargo check` passes for the affected crates on the pinned `1.96.0` toolchain, including the `try_update` call sites.

Fixes #1965.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: webern <matt.briggs@datadoghq.com>
Co-authored-by: jesse.szwedko <jesse.szwedko@datadoghq.com>

Author: jszwedko

.github/workflows/docs.yml

@@ -33,10 +33,12 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install -y protobuf-compiler
-      - name: Set up Rust Nightly
-        uses: actions-rust-lang/setup-rust-toolchain@46268bd060767258de96ed93c1251119784f2ab6 # v1.16
+      # `make generate-api-docs` installs and pins the nightly toolchain it needs (see
+      # RUST_NIGHTLY_VERSION in the Makefile); this step just provides rustup/cargo.
+      - name: Set up Rust
+        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1.17
         with:
-          toolchain: nightly
+          toolchain: stable
           cache: false
           rustflags: ""
       - name: Generate API documentation

Cargo.lock

@@ -37,6 +37,11 @@ MACOS_TEST_AGENT_INSTALL_DIR ?= /tmp/saluki-dda/datadog-agent
 export GO_BUILD_IMAGE ?= golang:1.23-bullseye
 export GO_APP_IMAGE ?= ubuntu:24.04
 
+# Pinned nightly toolchain shared by the Miri tests and API-doc generation, both of which rely on
+# nightly-only features. Keeping it in one variable ensures the two stay in lockstep; bump here to
+# move both at once.
+export RUST_NIGHTLY_VERSION ?= nightly-2026-07-05
+
 # Tool configuration.
 export AUTOINSTALL ?= true
 export CARGO_BIN_DIR := $(shell echo "${HOME}/.cargo/bin")
@@ -486,10 +491,10 @@ check-all: ## Check everything
 check-all: check-fmt check-clippy check-docs check-deny check-licenses check-unused-deps generate-api-docs check-features
 
 .PHONY: generate-api-docs
-generate-api-docs: check-rust-build-tools
+generate-api-docs: check-rust-build-tools ensure-rust-nightly
 generate-api-docs: ## Check that API documentation builds without errors
 	@echo "[*] Checking API documentation build..."
-	@RUSTDOCFLAGS="--enable-index-page -Zunstable-options" cargo +nightly doc --no-deps -Zrustdoc-map --lib
+	@RUSTDOCFLAGS="--enable-index-page -Zunstable-options" cargo +$(RUST_NIGHTLY_VERSION) doc --no-deps -Zrustdoc-map --lib
 
 .PHONY: check-clippy
 check-clippy: check-rust-build-tools
@@ -567,7 +572,7 @@ test-docs: ## Runs all doctests
 test-miri: check-rust-build-tools ensure-rust-miri
 test-miri: ## Runs all Miri-specific unit tests
 	@echo "[*] Running Miri-specific unit tests..."
-	cargo +nightly-2025-06-16 miri test -p stringtheory
+	cargo +$(RUST_NIGHTLY_VERSION) miri test -p stringtheory
 
 .PHONY: test-loom
 test-loom: check-rust-build-tools
@@ -725,15 +730,20 @@ provision-macos-test-env: ## Installs the pinned Datadog Agent ($(MACOS_TEST_AGE
 .PHONY: test-integration-macos-ci
 test-integration-macos-ci: build-panoramic build-adp-host provision-macos-test-env test-integration-macos-run ## CI entry point: builds binaries, ensures Agent + cert are provisioned, then runs the `mac`-runtime integration tests
 
-.PHONY: ensure-rust-miri
-ensure-rust-miri:
+.PHONY: ensure-rust-nightly
+ensure-rust-nightly:
 ifeq ($(shell command -v rustup >/dev/null || echo not-found), not-found)
-	$(error "Rustup must be present to install nightly toolchain/Miri component: https://www.rust-lang.org/tools/install")
+	$(error "Rustup must be present to install the nightly toolchain: https://www.rust-lang.org/tools/install")
 endif
-	@echo "[*] Installing/updating nightly Rust (2025-06-16) and Miri component..."
-	@rustup toolchain install nightly-2025-06-16 --component miri
+	@echo "[*] Installing/updating nightly Rust ($(RUST_NIGHTLY_VERSION))..."
+	@rustup toolchain install $(RUST_NIGHTLY_VERSION) --profile minimal
+
+.PHONY: ensure-rust-miri
+ensure-rust-miri: ensure-rust-nightly
+	@echo "[*] Installing/updating Miri component..."
+	@rustup component add miri --toolchain $(RUST_NIGHTLY_VERSION)
 	@echo "[*] Ensuring Miri is setup..."
-	@cargo +nightly-2025-06-16 miri setup
+	@cargo +$(RUST_NIGHTLY_VERSION) miri setup
 
 ##@ Antithesis
 

Makefile

@@ -1,6 +1,6 @@
 [package]
 name = "agent-data-plane"
-version = "1.2.2"
+version = "1.2.3"
 edition = { workspace = true }
 license = { workspace = true }
 repository = { workspace = true }

bin/agent-data-plane/Cargo.toml

@@ -21,10 +21,31 @@ static DD_URL_REGEX: LazyLock<Regex> =
 
 pub const DEFAULT_SITE: &str = "datadoghq.com";
 
+/// The primary endpoint URL that is constructed when both `site` and `dd_url` are at their defaults.
+///
+/// The Core Agent sends `dd_url` at this value even when the operator only configured `site`.
+/// A `dd_url` equal to this constant carries no override intent and must not shadow `site`.
+const DEFAULT_PRIMARY_ENDPOINT: &str = "https://app.datadoghq.com";
+
 fn default_site() -> String {
     DEFAULT_SITE.to_owned()
 }
 
+/// Deserializes an optional `dd_url`, treating the schema-default URL as absent.
+///
+/// The Core Agent always sends `dd_url` at its schema default (`https://app.datadoghq.com`) even
+/// when the operator only configured `site`. Filtering here, at deserialization, ensures that a
+/// value equal to the default is treated as `None`, allowing `site` to determine the endpoint. This
+/// only affects the serde path; programmatic callers such as `set_dd_url` bypass serde and are
+/// unaffected.
+fn deserialize_dd_url<'de, D>(deserializer: D) -> Result<Option<String>, D::Error>
+where
+    D: serde::Deserializer<'de>,
+{
+    let val = Option::<String>::deserialize(deserializer)?;
+    Ok(val.filter(|url| url.as_str() != DEFAULT_PRIMARY_ENDPOINT))
+}
+
 /// Error type for invalid endpoints.
 #[derive(Debug, Snafu)]
 #[snafu(context(suffix(false)))]
@@ -147,7 +168,7 @@ pub struct EndpointConfiguration {
     /// which are both useful when proxying traffic to an intermediate destination before forwarding to Datadog.
     ///
     /// Defaults to unset.
-    #[serde(default, alias = "url")]
+    #[serde(default, alias = "url", deserialize_with = "deserialize_dd_url")]
     dd_url: Option<String>,
 
     /// Enables sending data to multiple endpoints and/or with multiple API keys via dual shipping.
@@ -846,4 +867,63 @@ mod tests {
             .expect("error calculating override API endpoint");
         assert_eq!(expected_endpoint, resolved.endpoint().to_string());
     }
+
+    #[test]
+    fn deserialize_dd_url_filters_default_value() {
+        // The default dd_url (what the Agent sends when operator only configured site) should
+        // deserialize to None so that site takes precedence.
+        let config_str = r#"{"api_key": "test-key", "dd_url": "https://app.datadoghq.com"}"#;
+        let config: EndpointConfiguration = serde_json::from_str(config_str).expect("deserialization should succeed");
+        assert_eq!(None, config.dd_url);
+    }
+
+    #[test]
+    fn deserialize_dd_url_preserves_explicit_override() {
+        // A dd_url that differs from the default should deserialize as-is.
+        let config_str = r#"{"api_key": "test-key", "dd_url": "https://proxy.internal.example.com:3128"}"#;
+        let config: EndpointConfiguration = serde_json::from_str(config_str).expect("deserialization should succeed");
+        assert_eq!(
+            Some("https://proxy.internal.example.com:3128".to_string()),
+            config.dd_url
+        );
+    }
+
+    #[test]
+    fn set_dd_url_is_not_filtered() {
+        // Programmatic calls to set_dd_url bypass serde and are never filtered, even if set to the default value.
+        // This is important for MRF and other override paths that may explicitly set the default URL.
+        let config_str = r#"{"api_key": "test-key", "site": "datadoghq.eu"}"#;
+        let mut config: EndpointConfiguration =
+            serde_json::from_str(config_str).expect("deserialization should succeed");
+        config.set_dd_url("https://app.datadoghq.com".to_string());
+        assert_eq!(Some("https://app.datadoghq.com".to_string()), config.dd_url);
+    }
+
+    #[test]
+    fn site_takes_precedence_when_dd_url_is_default() {
+        // When dd_url is at its default (sent by Agent with source="default"), site should determine the endpoint.
+        // This is tested through deserialization so the default-filtering occurs.
+        let config_str = r#"{"api_key": "test-key", "site": "datadoghq.eu", "dd_url": "https://app.datadoghq.com"}"#;
+        let config: EndpointConfiguration = serde_json::from_str(config_str).expect("deserialization should succeed");
+
+        let resolved = config
+            .build_primary_endpoint(None)
+            .expect("error building primary endpoint");
+        // The site path applies a version prefix, so assert the host resolves to the eu site rather than the
+        // default US1 intake.
+        let host = resolved.endpoint().host_str().unwrap();
+        assert!(host.ends_with("datadoghq.eu"), "expected eu site, got {host}");
+    }
+
+    #[test]
+    fn explicit_dd_url_overrides_site() {
+        // A dd_url that diverges from the default should take precedence over site.
+        let config_str = r#"{"api_key": "test-key", "site": "datadoghq.eu", "dd_url": "https://dogpound.io/"}"#;
+        let config: EndpointConfiguration = serde_json::from_str(config_str).expect("deserialization should succeed");
+
+        let resolved = config
+            .build_primary_endpoint(None)
+            .expect("error building primary endpoint");
+        assert_eq!("dogpound.io", resolved.endpoint().host_str().unwrap());
+    }
 }

lib/saluki-components/src/common/datadog/endpoints.rs

@@ -122,7 +122,7 @@ where
                     // decrease the error count.
                     let _ = self
                         .error_count
-                        .fetch_update(AcqRel, Relaxed, |count| Some(count.saturating_sub(factor)));
+                        .try_update(AcqRel, Relaxed, |count| Some(count.saturating_sub(factor)));
                 }
                 None => {
                     debug!("Resetting error count to zero after successful response.");

lib/saluki-io/src/net/util/retry/policy/rolling_exponential.rs

@@ -45,7 +45,7 @@ impl GaugeStorage {
 impl GaugeFn for GaugeStorage {
     fn increment(&self, value: f64) {
         self.current
-            .fetch_update(SeqCst, SeqCst, |v| {
+            .try_update(SeqCst, SeqCst, |v| {
                 let new = f64::from_bits(v) + value;
                 Some(new.to_bits())
             })
@@ -54,7 +54,7 @@ impl GaugeFn for GaugeStorage {
 
     fn decrement(&self, value: f64) {
         self.current
-            .fetch_update(SeqCst, SeqCst, |v| {
+            .try_update(SeqCst, SeqCst, |v| {
                 let new = f64::from_bits(v) - value;
                 Some(new.to_bits())
             })