From ffe20f35af8b17a4888d4b13bce886eb80b3f5af Mon Sep 17 00:00:00 2001
From: ChrisRackauckas-Claude <accounts@chrisrackauckas.com>
Date: Thu, 4 Jun 2026 10:53:25 -0400
Subject: [PATCH] ci: add centralized sublibrary downgrade CI

Adds a caller workflow invoking the centralized
SciML/.github sublibrary-downgrade.yml@v1 reusable workflow, which
auto-discovers each lib/* package and runs downgrade-compat +
buildpkg + runtest against it.

Co-Authored-By: Chris Rackauckas <accounts@chrisrackauckas.com>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 .github/workflows/DowngradeSublibraries.yml | 23 +++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 .github/workflows/DowngradeSublibraries.yml

diff --git a/.github/workflows/DowngradeSublibraries.yml b/.github/workflows/DowngradeSublibraries.yml
new file mode 100644
index 0000000..f1f97cd
--- /dev/null
+++ b/.github/workflows/DowngradeSublibraries.yml
@@ -0,0 +1,23 @@
+name: Downgrade Sublibraries
+on:
+  pull_request:
+    branches:
+      - master
+    paths-ignore:
+      - 'docs/**'
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - 'docs/**'
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/master' }}
+jobs:
+  downgrade-sublibraries:
+    uses: "SciML/.github/.github/workflows/sublibrary-downgrade.yml@v1"
+    secrets: "inherit"
+    with:
+      julia-version: "lts"
+      skip: "Pkg,TOML,Statistics,LinearAlgebra,SparseArrays,InteractiveUtils,Random,Test,Markdown"
+      allow-reresolve: true