[ML] Make Appex QA/PyTorch tests version-aware on release branches

.buildkite/pipelines/derive_qa_stack_env.sh

@@ -0,0 +1,86 @@
+#!/bin/bash
+# Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+# or more contributor license agreements. Licensed under the Elastic License
+# 2.0 and the following additional limitation. Functionality enabled by the
+# files subject to the Elastic License 2.0 may only be used in production when
+# invoked by an Elasticsearch process with a license key installed that permits
+# use of machine learning features. You may not use this file except in
+# compliance with the Elastic License 2.0 and the foregoing additional
+# limitation.
+
+# Derive STACK_VERSION and ES_BRANCH for the Appex QA / PyTorch downstream
+# trigger (appex-qa-stateful-custom-ml-cpp-build-testing, generated by
+# elastic/qaf-tests). Without these the downstream falls back to its defaults
+# (ES_BRANCH=main, STACK_VERSION=<current main SNAPSHOT>) and then tries to
+# download an artifact named ml-cpp-<main-version>-SNAPSHOT-... from the parent
+# build. On a release-branch / backport build the parent produced
+# ml-cpp-<release-version>-SNAPSHOT-... instead, so the download misses
+# ("No artifacts found") and the QA build fails spuriously.
+#
+# This is meant to be SOURCED by the run_*_tests.yml.sh generators. Those
+# scripts pipe their stdout straight into `buildkite-agent pipeline upload`, so
+# this helper MUST NOT print anything to stdout — all diagnostics go to stderr.
+# Any values already present in the environment (e.g. from PR comment vars
+# GITHUB_PR_COMMENT_VAR_BRANCH / _VERSION) are respected and never overwritten.
+
+# STACK_VERSION: the ml-cpp product version for this build. gradle.properties'
+# elasticsearchVersion is exactly the artifact version (e.g. 9.5.0 on the 9.5
+# branch, 9.6.0 on main); qaf-tests strips/re-appends -SNAPSHOT itself.
+if [[ -z "${STACK_VERSION:-}" && -f gradle.properties ]]; then
+    _ml_cpp_version=$(sed -n 's/^elasticsearchVersion=//p' gradle.properties | tr -d '[:space:]')
+    if [[ -n "${_ml_cpp_version}" ]]; then
+        STACK_VERSION="${_ml_cpp_version}"
+    fi
+fi
+
+# ES_BRANCH: the Elasticsearch branch qaf-tests should build the custom
+# distribution from. It is "main" for the current development line and the
+# "<major>.<minor>" release branch otherwise. We decide by comparing this
+# build's version to ml-cpp main's version (fetched the same way the downstream
+# fetches ml-cpp/main assets), so there is no hard-coded "current dev minor" to
+# keep updating at feature freeze.
+if [[ -z "${ES_BRANCH:-}" && -n "${STACK_VERSION:-}" ]]; then
+    _main_version=$(python3 - <<'PY' 2>/dev/null
+import re, sys, urllib.request
+try:
+    with urllib.request.urlopen(
+        "https://raw.githubusercontent.com/elastic/ml-cpp/main/gradle.properties",
+        timeout=15,
+    ) as response:
+        text = response.read().decode("utf-8", "replace")
+    match = re.search(r"^elasticsearchVersion=(.+)$", text, re.M)
+    sys.stdout.write(match.group(1).strip() if match else "")
+except Exception:
+    sys.stdout.write("")
+PY
+)
+    _version_no_snapshot="${STACK_VERSION%-SNAPSHOT}"
+    _main_no_snapshot="${_main_version%-SNAPSHOT}"
+    if [[ -n "${_main_no_snapshot}" && "${_version_no_snapshot}" == "${_main_no_snapshot}" ]]; then
+        ES_BRANCH="main"
+    else
+        # major.minor of this build's version, e.g. 9.5.0 -> 9.5.
+        ES_BRANCH=$(printf '%s' "${_version_no_snapshot}" | awk -F. 'NF>=2 {print $1"."$2}')
+        if [[ -z "${_main_no_snapshot}" ]]; then
+            # Could not determine main's version (e.g. transient network issue).
+            # Fall back to the branch name: only treat recognised release-line
+            # branches as releases, otherwise preserve the historical default of
+            # main so ordinary PRs are unaffected.
+            _norm_branch="${BUILDKITE_BRANCH#elastic+}"
+            case "${_norm_branch}" in
+                backport/*|[0-9]*.[0-9]*|ci/ml-cpp-version-bump-*|ci/ml-cpp-minor-freeze-main-*)
+                    : # keep the derived major.minor
+                    ;;
+                *)
+                    ES_BRANCH="main"
+                    ;;
+            esac
+        fi
+        if [[ -z "${ES_BRANCH}" ]]; then
+            ES_BRANCH="main"
+        fi
+    fi
+fi
+
+export STACK_VERSION ES_BRANCH
+echo "derive_qa_stack_env: STACK_VERSION='${STACK_VERSION:-}' ES_BRANCH='${ES_BRANCH:-}'" >&2

.buildkite/pipelines/run_pytorch_tests.yml.sh

@@ -10,6 +10,13 @@
 
 SAFE_MESSAGE=$(printf '%s' "${BUILDKITE_MESSAGE}" | head -1 | sed -e 's/\\/\\\\/g' -e 's/"/\\"/g')
 
+# Derive STACK_VERSION / ES_BRANCH so release-branch and backport builds test
+# against the matching stack version and ES branch instead of the qaf-tests
+# defaults (main / current-dev SNAPSHOT). Silent on stdout by contract.
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+# shellcheck source=/dev/null
+source "${SCRIPT_DIR}/derive_qa_stack_env.sh"
+
 cat <<EOL
 steps:
   - label: "Trigger Appex PyTorch Tests :test_tube:"
@@ -28,3 +35,15 @@ steps:
       env:
         QAF_TESTS_TO_RUN: "pytorch_tests"
 EOL
+
+if [ "${ES_BRANCH}" != "" ]; then
+cat <<EOL
+        ES_BRANCH: "${ES_BRANCH}"
+EOL
+fi
+
+if [ "${STACK_VERSION}" != "" ]; then
+cat <<EOL
+        STACK_VERSION: "${STACK_VERSION}"
+EOL
+fi

.buildkite/pipelines/run_qa_tests.yml.sh

@@ -10,6 +10,14 @@
 
 SAFE_MESSAGE=$(printf '%s' "${BUILDKITE_MESSAGE}" | head -1 | sed -e 's/\\/\\\\/g' -e 's/"/\\"/g')
 
+# Derive STACK_VERSION / ES_BRANCH so release-branch and backport builds test
+# against the matching stack version and ES branch instead of the qaf-tests
+# defaults (main / current-dev SNAPSHOT). Any values already set (e.g. from PR
+# comment vars) are preserved. Silent on stdout by contract.
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+# shellcheck source=/dev/null
+source "${SCRIPT_DIR}/derive_qa_stack_env.sh"
+
 cat <<EOL
 steps:
   - label: "Trigger Appex QA Tests :test_tube:"