ci: cut PR CI time with a prebuilt image, ccache, and no QML cachegen (#22)

CI took about 5 min 10 s per PR on vm-201: 1.5 min of `pacman -Syu` and 3.5 min of build, half of it qmlcachegen compiling QML the tests never load. Now it takes **1 min 49 s with a cold ccache and 26 s with a warm one**.

- CI runs in a prebuilt Arch image with the build deps (`git.trivk.dev/tri/qtpotato-ci:latest`). `ci-image.yml` rebuilds it weekly, when its Dockerfile changes, or on demand. It builds on the runner's own Docker daemon, so vm-201 has the new image right away, since the runner does not re-pull tags it already has.
- CI configures with `QT_QML_NO_CACHEGEN=ON` and no debug info. Release and AUR builds keep both.
- ccache, kept between runs with `actions/cache`.
- Docs-only changes (`README.md`, `LICENSES/`) skip CI.

Pushing the image to the registry needed two workarounds. Gitea's Actions token cannot push container images, so it uses the `PACKAGE_TOKEN` secret from #21. Cloudflare rejects request bodies over 100 MB and `docker push` sends each layer in one request, so `regctl` (pinned by sha256) pushes the layers in 50 MB chunks.

Giving vm-201 more vCPUs is left out; it is an infra change.

Refs #20

Proof: on this PR, CI run 328 (cold ccache) took 1 min 49 s and run 332 (warm, 41/44 hits) took 26 s, both 8/8 tests. Image run 333 pushed the image, and the registry digest matches the runner's local image. A local build with the CI flags takes 74 steps instead of 154.

Reviewed with sol-loop: 3 rounds with gpt-6.1-sol. Sol verdict: approved

Created with Claude Opus 5.5 in Claude Code (T3 Code).
Reviewed-on: #22
Co-authored-by: Tri Vo Khac <git@trivk.dev>

.gitea/ci-image/Dockerfile

@@ -0,0 +1,7 @@
+# Arch Linux with QtPotato's build dependencies, so CI skips the pacman step.
+# Built and pushed by .gitea/workflows/ci-image.yml.
+FROM archlinux:latest
+RUN pacman -Syu --noconfirm --needed git nodejs base-devel cmake ninja ccache extra-cmake-modules \
+        qt6-base qt6-declarative kirigami ki18n kcoreaddons kcrash kconfig \
+        mpvqt qcoro qtkeychain-qt6 ffmpeg \
+    && rm -rf /var/cache/pacman/pkg/*

.gitea/workflows/arch-package.yml

@@ -0,0 +1,58 @@
+name: Arch package
+
+# Builds the qtpotato package from a release tag and publishes it to this Gitea's Arch
+# registry, so users can install it with pacman until it is on the AUR.
+on:
+  push:
+    tags: ['v*']
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: Release tag to package, e.g. v0.1.0
+        required: true
+
+permissions:
+  contents: read
+
+jobs:
+  package:
+    # Arch Linux only ships x86_64 images, so pick an amd64 runner.
+    runs-on: amd64
+    container: archlinux:latest
+    env:
+      TAG: ${{ inputs.tag || github.ref_name }}
+    steps:
+      - name: Install dependencies
+        run: |
+          pacman -Syu --noconfirm --needed git nodejs base-devel cmake ninja extra-cmake-modules \
+              qt6-base qt6-declarative kirigami ki18n kcoreaddons kcrash kconfig \
+              mpvqt qcoro qtkeychain-qt6 ffmpeg hicolor-icon-theme
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.tag || github.ref }}
+      - name: Build
+        run: |
+          version="${TAG#v}"
+          dir=/tmp/pkg
+          mkdir -p "$dir"
+          git config --global --add safe.directory "$PWD"
+          git archive --format=tar --prefix="qtpotato-$version/" HEAD | gzip -n > "$dir/qtpotato-$version.tar.gz"
+          sum="$(sha256sum "$dir/qtpotato-$version.tar.gz" | cut -d' ' -f1)"
+          sed -e "s/^pkgver=.*/pkgver=$version/" -e "s/^pkgrel=.*/pkgrel=1/" \
+              -e 's/^source=.*/source=("$pkgname-$pkgver.tar.gz")/' \
+              -e "s/^sha256sums=.*/sha256sums=('$sum')/" \
+              packaging/aur/qtpotato/PKGBUILD > "$dir/PKGBUILD"
+          # makepkg refuses to run as root.
+          useradd -m builder
+          chown -R builder "$dir"
+          su builder -c "cd $dir && makepkg --noconfirm"
+      - name: Publish
+        env:
+          # The package registry rejects the job token, so this is a personal access token
+          # with the write:package scope.
+          TOKEN: ${{ secrets.PACKAGE_TOKEN }}
+        run: |
+          for f in /tmp/pkg/qtpotato-[0-9]*.pkg.tar.zst; do
+              curl -fsS -X PUT -H "Authorization: token $TOKEN" --upload-file "$f" \
+                  "$GITHUB_SERVER_URL/api/packages/${GITHUB_REPOSITORY%%/*}/arch/qtpotato"
+          done

.gitea/workflows/ci-image.yml

@@ -0,0 +1,40 @@
+name: CI image
+
+# Builds the Arch image that ci.yml runs in, with the build dependencies preinstalled.
+# Rebuilt weekly to pick up Arch updates.
+on:
+  push:
+    branches: [main]
+    paths: ['.gitea/ci-image/**', '.gitea/workflows/ci-image.yml']
+  schedule:
+    - cron: '0 3 * * 1'
+  workflow_dispatch:
+
+jobs:
+  image:
+    # The build runs on the runner's own Docker daemon, so the amd64 runner has the new
+    # image locally right away. It does not re-pull tags it already has.
+    runs-on: amd64
+    env:
+      IMAGE: git.trivk.dev/tri/qtpotato-ci:latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Build
+        # No layer cache, so each rebuild picks up the week's Arch updates.
+        run: docker build --pull --no-cache -t "$IMAGE" .gitea/ci-image
+      - name: Push
+        # Gitea's Actions token cannot push to the container registry, so this uses an
+        # access token with the write:package scope. Cloudflare rejects request bodies over
+        # 100 MB and docker push sends each layer in one request, so regctl pushes the
+        # layers in 50 MB chunks instead.
+        env:
+          TOKEN: ${{ secrets.PACKAGE_TOKEN }}
+        run: |
+          curl -fsSL -o /usr/local/bin/regctl \
+              https://github.com/regclient/regclient/releases/download/v0.11.7/regctl-linux-amd64
+          echo "3737fbbdd791e04e7a831640b681f3397a376498e80e2ad9b1b2d27296f239bc  /usr/local/bin/regctl" | sha256sum -c
+          chmod +x /usr/local/bin/regctl
+          echo "$TOKEN" | regctl registry login git.trivk.dev -u "${{ github.repository_owner }}" --pass-stdin
+          regctl registry set git.trivk.dev --blob-chunk 52428800 --blob-max 52428800
+          docker save "$IMAGE" -o "$RUNNER_TEMP/image.tar"
+          regctl image import "$IMAGE" "$RUNNER_TEMP/image.tar"

.gitea/workflows/ci.yml

@@ -0,0 +1,42 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+    paths-ignore: ['README.md', 'LICENSES/**']
+  pull_request:
+    paths-ignore: ['README.md', 'LICENSES/**']
+
+jobs:
+  build:
+    # Arch Linux only ships x86_64 images, so pick an amd64 runner.
+    runs-on: amd64
+    # Arch with the build dependencies preinstalled; see ci-image.yml.
+    container: git.trivk.dev/tri/qtpotato-ci:latest
+    env:
+      CCACHE_DIR: ${{ github.workspace }}/.ccache
+      # Keep hits across weekly image rebuilds when the compiler did not change.
+      CCACHE_COMPILERCHECK: content
+      CCACHE_MAXSIZE: 500M
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/cache@v4
+        with:
+          path: .ccache
+          key: ccache-${{ github.sha }}
+          restore-keys: ccache-
+      - name: Configure
+        # The tests do not load QML, so skip QML cachegen and debug info: they take over
+        # half of the build. Release and AUR builds keep both.
+        run: |
+          cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_FLAGS_DEBUG=-O0 \
+              -DQT_QML_NO_CACHEGEN=ON -DCMAKE_CXX_COMPILER_LAUNCHER=ccache -DBUILD_TESTING=ON
+      - name: Build
+        run: |
+          ccache -z
+          cmake --build build
+          ccache -s
+      - name: Test
+        env:
+          QT_QPA_PLATFORM: offscreen
+        run: ctest --test-dir build --output-on-failure

.gitea/workflows/release.yml

@@ -0,0 +1,42 @@
+name: Release
+
+on:
+  push:
+    tags: ['v*']
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    # Arch Linux only ships x86_64 images, so pick an amd64 runner.
+    runs-on: amd64
+    container: archlinux:latest
+    steps:
+      - name: Install dependencies
+        run: |
+          pacman -Syu --noconfirm --needed git nodejs curl jq
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      - name: Source tarball
+        run: |
+          git config --global --add safe.directory "$PWD"
+          version="${GITHUB_REF_NAME#v}"
+          mkdir -p dist
+          git archive --format=tar --prefix="qtpotato-$version/" "$GITHUB_REF_NAME" \
+              | gzip -n > "dist/qtpotato-$version.tar.gz"
+      - name: Publish release
+        env:
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          cd dist
+          sha256sum -- * > SHA256SUMS
+          api="$GITHUB_SERVER_URL/api/v1/repos/$GITHUB_REPOSITORY"
+          id=$(jq -n --arg tag "$GITHUB_REF_NAME" '{tag_name: $tag, name: ("QtPotato " + ($tag | ltrimstr("v")))}' \
+              | curl -fsS -X POST -H "Authorization: token $TOKEN" -H 'Content-Type: application/json' \
+                  --data @- "$api/releases" | jq -r .id)
+          for f in *; do
+              curl -fsS -X POST -H "Authorization: token $TOKEN" \
+                  -F "attachment=@$f" "$api/releases/$id/assets?name=$f" > /dev/null
+          done

README.md

@@ -24,6 +24,42 @@ translate a whole subtitle track with any OpenAI-compatible API and show the res
   auto-hiding controls.
 - Follows your Plasma style, colours and icons.
 
+## Installing on Arch Linux
+
+### From the pacman repository
+
+Every release is built and published to this Gitea's package registry. Import the signing key
+once:
+
+```sh
+curl -O https://git.trivk.dev/api/packages/tri/arch/repository.key
+sudo pacman-key --add repository.key
+sudo pacman-key --lsign-key 9C48725295A5F54A6A491CF86B273DD49890E8A7
+```
+
+Then add the repository to `/etc/pacman.conf` and install:
+
+```ini
+[qtpotato]
+SigLevel = Required
+Server = https://git.trivk.dev/api/packages/tri/arch/$repo/$arch
+```
+
+```sh
+sudo pacman -Syu qtpotato
+```
+
+The package is built against Arch's current Qt and KDE Frameworks. If it breaks after a system
+update before a new release is out, build it from source as below.
+
+### From the PKGBUILD
+
+```sh
+git clone https://git.trivk.dev/tri/QtPotato.git
+cd QtPotato/packaging/aur/qtpotato   # or qtpotato-git for the latest main
+makepkg -si
+```
+
 ## Building
 
 ### Dependencies

autotests/playlistmodeltest.cpp

@@ -33,6 +33,12 @@ private:
     }
 
 private Q_SLOTS:
+    void initTestCase()
+    {
+        // The C locale's collation is case-sensitive, so the sort order would depend on $LANG.
+        QLocale::setDefault(QLocale(QLocale::English, QLocale::UnitedStates));
+    }
+
     void sortsEpisodesNaturallyAndSkipsOtherFiles()
     {
         QTemporaryDir dir;

packaging/aur/qtpotato-git/.SRCINFO

@@ -0,0 +1,31 @@
+pkgbase = qtpotato-git
+	pkgdesc = KDE video player built on mpv that translates subtitles with an LLM (development version)
+	pkgver = 0.1.0
+	pkgrel = 1
+	url = https://git.trivk.dev/tri/QtPotato
+	arch = x86_64
+	license = GPL-3.0-or-later
+	makedepends = git
+	makedepends = cmake
+	makedepends = ninja
+	makedepends = extra-cmake-modules
+	depends = qt6-base
+	depends = qt6-declarative
+	depends = kirigami
+	depends = ki18n
+	depends = kcoreaddons
+	depends = kcrash
+	depends = kconfig
+	depends = mpvqt
+	depends = qcoro
+	depends = qtkeychain-qt6
+	depends = ffmpeg
+	depends = hicolor-icon-theme
+	optdepends = qqc2-desktop-style: Plasma look for the interface
+	optdepends = plasma-integration: Plasma file dialogs, colours and icons
+	provides = qtpotato=0.1.0
+	conflicts = qtpotato
+	source = qtpotato::git+https://git.trivk.dev/tri/QtPotato.git
+	sha256sums = SKIP
+
+pkgname = qtpotato-git

packaging/aur/qtpotato-git/PKGBUILD

@@ -0,0 +1,44 @@
+# Maintainer: Tri Vo Khac
+
+pkgname=qtpotato-git
+_pkgname=qtpotato
+pkgver=0.1.0
+pkgrel=1
+pkgdesc='KDE video player built on mpv that translates subtitles with an LLM (development version)'
+arch=('x86_64')
+url='https://git.trivk.dev/tri/QtPotato'
+license=('GPL-3.0-or-later')
+depends=('qt6-base' 'qt6-declarative' 'kirigami' 'ki18n' 'kcoreaddons' 'kcrash' 'kconfig'
+         'mpvqt' 'qcoro' 'qtkeychain-qt6' 'ffmpeg' 'hicolor-icon-theme')
+makedepends=('git' 'cmake' 'ninja' 'extra-cmake-modules')
+optdepends=('qqc2-desktop-style: Plasma look for the interface'
+            'plasma-integration: Plasma file dialogs, colours and icons')
+provides=("$_pkgname=$pkgver")
+conflicts=("$_pkgname")
+source=("$_pkgname::git+$url.git")
+sha256sums=('SKIP')
+
+pkgver() {
+  cd "$_pkgname"
+  if git describe --tags --long >/dev/null 2>&1; then
+    git describe --tags --long --abbrev=7 | sed 's/^v//;s/\([^-]*-g\)/r\1/;s/-/./g'
+  else
+    printf 'r%s.%s' "$(git rev-list --count HEAD)" "$(git rev-parse --short=7 HEAD)"
+  fi
+}
+
+build() {
+  cmake -B build -S "$_pkgname" -G Ninja \
+    -DCMAKE_BUILD_TYPE=None \
+    -DCMAKE_INSTALL_PREFIX=/usr \
+    -DBUILD_TESTING=ON
+  cmake --build build
+}
+
+check() {
+  QT_QPA_PLATFORM=offscreen ctest --test-dir build --output-on-failure
+}
+
+package() {
+  DESTDIR="$pkgdir" cmake --install build
+}

packaging/aur/qtpotato/.SRCINFO

@@ -0,0 +1,28 @@
+pkgbase = qtpotato
+	pkgdesc = KDE video player built on mpv that translates subtitles with an LLM
+	pkgver = 0.1.0
+	pkgrel = 1
+	url = https://git.trivk.dev/tri/QtPotato
+	arch = x86_64
+	license = GPL-3.0-or-later
+	makedepends = cmake
+	makedepends = ninja
+	makedepends = extra-cmake-modules
+	depends = qt6-base
+	depends = qt6-declarative
+	depends = kirigami
+	depends = ki18n
+	depends = kcoreaddons
+	depends = kcrash
+	depends = kconfig
+	depends = mpvqt
+	depends = qcoro
+	depends = qtkeychain-qt6
+	depends = ffmpeg
+	depends = hicolor-icon-theme
+	optdepends = qqc2-desktop-style: Plasma look for the interface
+	optdepends = plasma-integration: Plasma file dialogs, colours and icons
+	source = https://git.trivk.dev/tri/QtPotato/releases/download/v0.1.0/qtpotato-0.1.0.tar.gz
+	sha256sums = 8ac4cd95e04880411f16009478765f698c1ba84538c776e68a431033e10ae837
+
+pkgname = qtpotato

packaging/aur/qtpotato/PKGBUILD

@@ -0,0 +1,33 @@
+# Maintainer: Tri Vo Khac
+
+pkgname=qtpotato
+pkgver=0.1.0
+pkgrel=1
+pkgdesc='KDE video player built on mpv that translates subtitles with an LLM'
+arch=('x86_64')
+url='https://git.trivk.dev/tri/QtPotato'
+license=('GPL-3.0-or-later')
+depends=('qt6-base' 'qt6-declarative' 'kirigami' 'ki18n' 'kcoreaddons' 'kcrash' 'kconfig'
+         'mpvqt' 'qcoro' 'qtkeychain-qt6' 'ffmpeg' 'hicolor-icon-theme')
+makedepends=('cmake' 'ninja' 'extra-cmake-modules')
+optdepends=('qqc2-desktop-style: Plasma look for the interface'
+            'plasma-integration: Plasma file dialogs, colours and icons')
+source=("$url/releases/download/v$pkgver/$pkgname-$pkgver.tar.gz")
+# Filled in by update-pkgbuild.sh from the release's SHA256SUMS.
+sha256sums=('8ac4cd95e04880411f16009478765f698c1ba84538c776e68a431033e10ae837')
+
+build() {
+  cmake -B build -S "$pkgname-$pkgver" -G Ninja \
+    -DCMAKE_BUILD_TYPE=None \
+    -DCMAKE_INSTALL_PREFIX=/usr \
+    -DBUILD_TESTING=ON
+  cmake --build build
+}
+
+check() {
+  QT_QPA_PLATFORM=offscreen ctest --test-dir build --output-on-failure
+}
+
+package() {
+  DESTDIR="$pkgdir" cmake --install build
+}

packaging/aur/update-pkgbuild.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+# Point the qtpotato PKGBUILD at a published release and regenerate .SRCINFO.
+#
+# Usage: packaging/aur/update-pkgbuild.sh <version>   (e.g. 0.2.0, after the v0.2.0 release)
+set -euo pipefail
+
+version="${1#v}"
+dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+url="https://git.trivk.dev/tri/QtPotato/releases/download/v$version"
+sum="$(curl -fsSL "$url/SHA256SUMS" | awk -v f="qtpotato-$version.tar.gz" '$2 == f { print $1 }')"
+[[ -n "$sum" ]] || { echo "qtpotato-$version.tar.gz not found in $url/SHA256SUMS" >&2; exit 1; }
+
+cd "$dir/qtpotato"
+sed -i -e "s/^pkgver=.*/pkgver=$version/" -e "s/^pkgrel=.*/pkgrel=1/" \
+    -e "s/^sha256sums=.*/sha256sums=('$sum')/" PKGBUILD
+makepkg --printsrcinfo > .SRCINFO
+cd "$dir/qtpotato-git"
+makepkg --printsrcinfo > .SRCINFO