ci: make fat qt libs thin (#6281)

* ci: strip fat qt binaries

* parallelize

* cache thin qt

* print libs

* change qt install dir in the action

* move qt install logic to separate job

* lookup only

* debug: show contents of QTDIR

* enableCrossOsArchive also when saving

* check one dir up

* change install dir

* keep debugging

* try deleting cache

* force delete cache

* pass gh_token

* pass missing params

* use api

* change cache key, disable cross os archive

* move job directly to steps

* add comments

* set cache param directly

* address comments

* fixup

* Update .ci/thin_macos_qtlib.sh

* resolve qt version

* move resolution to separate script

* use single line for run:

* improve error handling in new scripts

---------

Co-authored-by: ebbit1q <ebbit1q@gmail.com>

.ci/compile.sh

@@ -156,6 +156,18 @@ function ccachestatsverbose() {
 
 # Compile
 if [[ $RUNNER_OS == macOS ]]; then
+  # QTDIR is needed for macOS since we actually only use the cached thin Qt binaries instead of the install-qt-action,
+  # which sets a few environment variables
+  if QTDIR=$(find "$GITHUB_WORKSPACE/Qt" -depth -maxdepth 2 -name macos -type d -print -quit); then
+    echo "found QTDIR at $QTDIR"
+  else
+    echo "could not find QTDIR!"
+    exit 2
+  fi
+  # the qtdir is located at Qt/[qtversion]/macos
+  # we use find to get the first subfolder with the name "macos"
+  # this works independent of the qt version as there should be only one version installed on the runner at a time
+  export QTDIR
 
   if [[ $TARGET_MACOS_VERSION ]]; then
     # CMAKE_OSX_DEPLOYMENT_TARGET is a vanilla cmake flag needed to compile to target macOS version

.ci/resolve_latest_aqt_qt_version.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+
+# This script is used to resolve the latest patch version of Qt using aqtinstall.
+# It interprets wildcards to get the latest patch version. E.g. "6.6.*" -> "6.6.3".
+
+# This script is meant to be used by the ci enironment.
+# It uses the runner's GITHUB_OUTPUT env variable.
+
+# Usage example: .ci/resolve_latest_aqt_qt_version.sh "6.6.*"
+
+qt_spec=$1
+if [[ ! $qt_spec ]]; then
+  echo "usage: $0 [version]"
+  exit 2
+fi
+
+# If version is already specific (no wildcard), use it as-is
+if [[ $qt_spec != *"*" ]]; then
+  echo "version $qt_spec is already resolved"
+  echo "version=$qt_spec" >> "$GITHUB_OUTPUT"
+  exit 0
+fi
+
+if ! hash aqt; then
+  echo "aqt could not be found, has aqtinstall been installed?"
+  exit 2
+fi
+
+# Resolve latest patch
+if ! qt_resolved=$(aqt list-qt mac desktop --spec "$qt_spec" --latest-version); then
+  exit 1
+fi
+
+echo "resolved $qt_spec to $qt_resolved"
+if [[ ! $qt_resolved ]]; then
+  echo "Error: Could not resolve Qt version for $qt_spec"
+  exit 1
+fi
+
+echo "version=$qt_resolved" >> "$GITHUB_OUTPUT"

.ci/thin_macos_qtlib.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+# The macos binaries from aqt are fat (universal), so we thin them to the target architecture to reduce the size of
+# the packages and caches using lipo.
+
+# This script is meant to be used by the ci enironment on macos runners only.
+# It uses the runner's GITHUB_WORKSPACE env variable.
+arch=$(uname -m)
+nproc=$(sysctl -n hw.ncpu)
+
+function thin() {
+  local libfile=$1
+  if [[ $(file -b --mime-type "$libfile") == application/x-mach-binary* ]]; then
+    echo "Processing $libfile"
+    lipo "$libfile" -thin "$arch" -output "$libfile"
+  fi
+  return 0
+}
+export -f thin  # export to allow use in xargs
+export arch
+set -eo pipefail
+
+echo "::group::Thinning Qt libraries to $arch using $nproc cores"
+find "$GITHUB_WORKSPACE/Qt" -type f -print0 | xargs -0 -n1 -P"$nproc" -I{} bash -c "thin '{}'"
+echo "::endgroup::"

.github/workflows/desktop-build.yml

@@ -262,7 +262,6 @@ jobs:
             qt_version: 6.6.*
             qt_arch: clang_64
             qt_modules: qtimageformats qtmultimedia qtwebsockets
-            cache_qt: false # qt caches take too much space for macOS (1.1Gi)
             cmake_generator: Ninja
             use_ccache: 1
 
@@ -278,7 +277,6 @@ jobs:
             qt_version: 6.6.*
             qt_arch: clang_64
             qt_modules: qtimageformats qtmultimedia qtwebsockets
-            cache_qt: false
             cmake_generator: Ninja
             use_ccache: 1
 
@@ -294,7 +292,6 @@ jobs:
             qt_version: 6.6.*
             qt_arch: clang_64
             qt_modules: qtimageformats qtmultimedia qtwebsockets
-            cache_qt: false
             cmake_generator: Ninja
             use_ccache: 1
 
@@ -307,7 +304,6 @@ jobs:
             qt_version: 6.6.*
             qt_arch: clang_64
             qt_modules: qtimageformats qtmultimedia qtwebsockets
-            cache_qt: false
             cmake_generator: Ninja
             use_ccache: 1
 
@@ -320,7 +316,6 @@ jobs:
             artifact_name: Windows7-installer
             qt_version: 5.15.*
             qt_arch: win64_msvc2019_64
-            cache_qt: true
             cmake_generator: "Visual Studio 17 2022"
             cmake_generator_platform: x64
 
@@ -334,7 +329,6 @@ jobs:
             qt_version: 6.6.*
             qt_arch: win64_msvc2019_64
             qt_modules: qtimageformats qtmultimedia qtwebsockets
-            cache_qt: true
             cmake_generator: "Visual Studio 17 2022"
             cmake_generator_platform: x64
 
@@ -375,13 +369,57 @@ jobs:
           key: ccache-${{matrix.runner}}-${{matrix.soc}}-${{matrix.type}}-${{env.BRANCH_NAME}}
           restore-keys: ccache-${{matrix.runner}}-${{matrix.soc}}-${{matrix.type}}-
 
-      - name: Install Qt ${{matrix.qt_version}}
+      - name: Install aqtinstall
+        if: matrix.os == 'macOS'
+        run: pipx install aqtinstall
+
+      # Checking if there's a newer, uncached version of Qt available to install via aqtinstall
+      - name: Resolve latest Qt patch version
+        if: matrix.os == 'macOS'
+        id: resolve_qt_version
+        shell: bash
+        # Ouputs the version of Qt to install via aqtinstall
+        run: .ci/resolve_latest_aqt_qt_version.sh "${{matrix.qt_version}}"
+
+      - name: Restore thin Qt ${{ steps.resolve_qt_version.outputs.version }} libraries (${{ matrix.soc }} macOS)
+        if: matrix.os == 'macOS'
+        id: restore_qt
+        uses: actions/cache/restore@v4
+        with:
+          path: ${{ github.workspace }}/Qt
+          key: thin-qt-macos-${{ matrix.soc }}-${{ steps.resolve_qt_version.outputs.version }}
+
+      # Using jurplel/install-qt-action to install Qt without using brew
+      # qt build using vcpkg either just fails or takes too long to build
+      - name: Install fat Qt ${{ steps.resolve_qt_version.outputs.version }} (${{ matrix.soc }} macOS)
+        if: matrix.os == 'macOS' && steps.restore_qt.outputs.cache-hit != 'true'
+        uses: jurplel/install-qt-action@v4
+        with:
+          cache: false
+          version: ${{ steps.resolve_qt_version.outputs.version }}
+          arch: ${{matrix.qt_arch}}
+          modules: ${{matrix.qt_modules}}
+          dir: ${{github.workspace}}
+
+      - name: Thin Qt libraries (${{ matrix.soc }} macOS)
+        if: matrix.os == 'macOS' && steps.restore_qt.outputs.cache-hit != 'true'
+        run: .ci/thin_macos_qtlib.sh
+
+      - name: Cache thin Qt libraries (${{ matrix.soc }} macOS)
+        if: matrix.os == 'macOS' && steps.restore_qt.outputs.cache-hit != 'true'
+        uses: actions/cache/save@v4
+        with:
+          path: ${{ github.workspace }}/Qt
+          key: thin-qt-macos-${{ matrix.soc }}-${{ steps.resolve_qt_version.outputs.version }}
+
+      - name: Install Qt ${{matrix.qt_version}} (Windows)
+        if: matrix.os == 'Windows'
         uses: jurplel/install-qt-action@v4
         with:
           version: ${{matrix.qt_version}}
           arch: ${{matrix.qt_arch}}
           modules: ${{matrix.qt_modules}}
-          cache: ${{matrix.cache_qt}}
+          cache: true
 
       - name: Setup vcpkg cache
         id: vcpkg-cache