Add CircleCI semver-compatibility check job for release branches

.circleci/config.yml

@@ -727,6 +727,22 @@ jobs:
       - clear_environment:
           cache_key: v4.2.0-rust-1.88.0-cargo-audit-cache
 
+  check-cargo-semver-checks:
+    executor: rust-docker
+    resource_class: << pipeline.parameters.twoxlarge >>
+    steps:
+      - checkout:
+          method: full
+      - setup_environment:
+          cache_key: v4.2.0-rust-1.88.0-cargo-semver-checks-cache
+      - run:
+          name: Check for semver violations
+          no_output_timeout: 15m
+          command: |
+            bash ./.circleci/semver-checks.sh
+      - clear_environment:
+          cache_key: v4.2.0-rust-1.88.0-cargo-semver-checks-cache
+
   check-clippy:
     executor: rust-docker
     resource_class: << pipeline.parameters.medium >>
@@ -850,6 +866,14 @@ workflows:
                 - testnet
                 - mainnet
                 - staging
+      - check-cargo-semver-checks:
+          filters:
+            branches:
+              only:
+                - canary
+                - testnet
+                - mainnet
+                - staging
 
   snarkos-workflow:
     jobs:

.circleci/semver-checks.sh

@@ -0,0 +1,13 @@
+#! /bin/bash
+
+set -x
+
+BASELINE_REV=5233959ad4 # UPDATE ME ON NECESSARY BREAKING CHANGES
+
+# Ensure that the command is installed.
+cargo install cargo-semver-checks@0.43.0 --locked
+
+# Ensure we can find the baseline revision
+git fetch --unshallow || true
+
+cargo semver-checks --workspace --default-features --baseline-rev $BASELINE_REV