Update CI pipeline to only run checks step on version bump PRs (sol…

…ana-labs#29243)

* Add logic to buildkite pipeline so version bump PRs don't run the full CI

ci/buildkite-pipeline.sh

@@ -311,6 +311,29 @@ pull_or_push_steps() {
     wait_step
   fi
 
+  # Version bump PRs are an edge case that can skip most of the CI steps
+  if affects .toml$ && affects .lock$ && ! affects_other_than .toml$ .lock$; then
+    optional_old_version_number=$(git diff "$BUILDKITE_PULL_REQUEST_BASE_BRANCH"..HEAD validator/Cargo.toml | \
+      grep -e "^-version" | sed  's/-version = "\(.*\)"/\1/')
+    echo "optional_old_version_number: ->$optional_old_version_number<-"
+    new_version_number=$(grep -e  "^version = " validator/Cargo.toml | sed 's/version = "\(.*\)"/\1/')
+    echo "new_version_number: ->$new_version_number<-"
+
+    # Every line in a version bump diff will match one of these patterns. Since we're using grep -v the output is the
+    # lines that don't match. Any diff that produces output here is not a version bump.
+    # | cat is a no-op. If this pull request is a version bump then grep will output no lines and have an exit code of 1.
+    # Piping the output to cat prevents that non-zero exit code from exiting this script
+    diff_other_than_version_bump=$(git diff "$BUILDKITE_PULL_REQUEST_BASE_BRANCH"..HEAD | \
+      grep -vE "^ |^@@ |^--- |^\+\+\+ |^index |^diff |^-( \")?solana.*$optional_old_version_number|^\+( \")?solana.*$new_version_number|^-version|^\+version"|cat)
+    echo "diff_other_than_version_bump: ->$diff_other_than_version_bump<-"
+
+    if [ -z "$diff_other_than_version_bump" ]; then
+      echo "Diff only contains version bump."
+      command_step checks ". ci/rust-version.sh; ci/docker-run.sh \$\$rust_nightly_docker_image ci/test-checks.sh" 20
+      exit 0
+    fi
+  fi
+
   # Run the full test suite by default, skipping only if modifications are local
   # to some particular areas of the tree
   if affects_other_than ^.buildkite ^.mergify .md$ ^docs/ ^web3.js/ ^explorer/ ^.gitbook; then