From b4be7cfa391c54a0f23e24f0646651a3999b206f Mon Sep 17 00:00:00 2001
From: Luke Street <luke@street.dev>
Date: Thu, 14 Aug 2025 19:05:46 -0600
Subject: [PATCH] Add build cache to CI workflow

NOTE: This requires an update to your build container. See
https://github.com/encounter/dtk-template-build/commit/e132563a5a88c58b933022f435cfd5a784d7069b

This normalizes file modtimes with git-restore-mtime, and caches
the build directory. Subsequent runs will only rebuild the files
that have changed.
---
 .github.example/workflows/build.yml | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/.github.example/workflows/build.yml b/.github.example/workflows/build.yml
index e713413..8593298 100644
--- a/.github.example/workflows/build.yml
+++ b/.github.example/workflows/build.yml
@@ -22,15 +22,30 @@ jobs:
     - name: Checkout
       uses: actions/checkout@v4
       with:
+        fetch-depth: 0
         submodules: recursive
 
     # Set Git config
     - name: Git config
       run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
 
+    # Normalize file mod times
+    - name: Restore timestamps
+      run: uv run https://raw.githubusercontent.com/MestreLion/git-tools/refs/tags/v2022.12/git-restore-mtime
+
     # Copy the original files to the workspace
     - name: Prepare
-      run: cp -R /orig .
+      run: cp -a /orig .
+
+    # Restore cached files
+    - name: Cache build
+      uses: actions/cache@v4
+      with:
+        path: |
+          build
+          .ninja_deps
+          .ninja_log
+        key: ${{ runner.os }}-${{ matrix.version }}
 
     # Build the project
     - name: Build