feat: install mergify-cli from prebuilt release binary

Replace the Python + uv install path (`uv tool install mergify-cli`) with the
mergify-cli prebuilt binary, installed via the CLI's own `install.sh` installer.

Why delegate to install.sh rather than re-implement the download/verify:
- install.sh owns platform detection, asset naming, and SHA256SUMS
  verification, so the action doesn't duplicate that logic or have to track it
  when the asset naming changes (it already changed once between releases).
- For a pinned version we fetch install.sh from that release tag (its asset
  naming matches the binary it installs); for `latest`/empty we fetch it from
  `main` and let the installer resolve the latest release.

Details:
- Fetch install.sh (tag or main), run it with MERGIFY_VERSION +
  MERGIFY_INSTALL_DIR, add the dir to $GITHUB_PATH.
- The `mergify_cli_version` output is read back from `mergify --version` (the
  binary reports its real version), accurate for both pinned and `latest`.
- Default bumped to 2026.6.16.1, the first release with prebuilt binaries +
  install.sh under the canonical versioned asset naming.
- Renovate datasource moved pypi -> github-releases (Mergifyio/mergify-cli,
  pep440).
- CI test-install is a matrix over the target triples install.sh supports
  (linux/macos, x86_64 + aarch64).

install.sh currently supports Linux and macOS only; Windows is picked up
automatically once install.sh ships a Windows path.

BREAKING CHANGE: the `python_version` input is removed (no Python is used) and
the action no longer provisions Python/uv on PATH as a side effect.

Fixes MRGFY-7660
Change-Id: If70ad03ddf01ec196f051fef6489b68904d02b20

Author: sileht

.github/workflows/ci.yaml

@@ -61,21 +61,39 @@ jobs:
 
   test-install:
     timeout-minutes: 5
-    runs-on: ubuntu-24.04
+    # One runner per target triple install.sh supports, so every detection +
+    # extraction path is exercised: linux+macos on both x86_64 and aarch64.
+    # (Windows is added once install.sh ships a Windows path.)
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-24.04        # x86_64-unknown-linux-gnu
+          - ubuntu-24.04-arm    # aarch64-unknown-linux-gnu
+          - macos-15-intel      # x86_64-apple-darwin
+          - macos-15            # aarch64-apple-darwin
+    runs-on: ${{ matrix.os }}
+    defaults:
+      run:
+        shell: bash
     steps:
       - name: Checkout 🛎️
         uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
 
       - name: Install pinned mergify-cli
         id: pinned
         uses: ./
+        with:
+          mergify_cli_version: 2026.6.16.1
 
       - name: Assert pinned install
         env:
           VERSION: ${{ steps.pinned.outputs.mergify_cli_version }}
         run: |
-          test -n "$VERSION"
-          mergify --version
+          # Compare against the literal requested version (not the action's own
+          # readback), so a regression that installs the wrong version fails CI.
+          test "$VERSION" = "2026.6.16.1"
+          test "$(mergify --version | awk '{print $NF}')" = "2026.6.16.1"
 
       - name: Install latest mergify-cli
         id: latest
@@ -88,7 +106,7 @@ jobs:
           VERSION: ${{ steps.latest.outputs.mergify_cli_version }}
         run: |
           test -n "$VERSION"
-          mergify --version
+          test "$(mergify --version | awk '{print $NF}')" = "$VERSION"
 
   all-greens:
     if: ${{ !cancelled() }}

README.md

@@ -1,10 +1,15 @@
 # setup-cli
 
-GitHub Action to install the [Mergify CLI](https://pypi.org/project/mergify-cli/)
+GitHub Action to install the [Mergify CLI](https://github.com/Mergifyio/mergify-cli)
 (`mergify-cli`) with version pinning and Renovate autoupdate.
 
-It sets up Python, installs `uv`, then installs `mergify-cli` (pinned by default,
-`latest` supported) and exposes the resolved version as an output.
+It installs the prebuilt `mergify` binary via the mergify-cli `install.sh`
+installer, which downloads the binary from the GitHub release and verifies it
+against the release `SHA256SUMS`. For a pinned version the installer is fetched
+from that release tag; `latest` uses `main`. The action then puts the binary on
+`PATH` and exposes the installed version as an output. Pinned by default,
+`latest` supported. No Python or toolchain is required; Linux and macOS are
+supported.
 
 More information on https://mergify.com
 
@@ -35,13 +40,12 @@ Pin a specific `mergify-cli` version, or install the latest one:
 
 | Input | Type | Required | Default | Description |
 | --- | --- | --- | --- | --- |
-| `mergify_cli_version` | string | false | `2026.6.8.1` | Version of mergify-cli to install. Use `latest` to install the latest released version without pinning. |
-| `python_version` | string | false | `3.14` | Python version to set up for the install (passed to actions/setup-python). |
+| `mergify_cli_version` | string | false | `2026.6.16.1` | Version of mergify-cli to install. Use `latest` to install the latest released version without pinning. |
 
 <!-- AUTO-DOC-INPUT:END -->
 
 ## Outputs
 
 | Output | Description |
 | --- | --- |
-| `mergify_cli_version` | The `mergify-cli` version that was installed. Resolved from the installed package metadata, so it reflects the real version even when `latest` or an empty input was requested. |
+| `mergify_cli_version` | The `mergify-cli` version that was installed. Read back from the installed binary, so it reflects the real version even when `latest` or an empty input was requested. |

action.yml

@@ -1,5 +1,5 @@
 name: Setup Mergify CLI
-description: Install the Mergify CLI (mergify-cli) with version pinning.
+description: Install the Mergify CLI (mergify-cli) prebuilt binary with version pinning.
 author: Mergify
 branding:
   icon: terminal
@@ -9,48 +9,55 @@ inputs:
     description: |
       Version of mergify-cli to install. Use `latest` to install the latest
       released version without pinning.
-    # renovate: datasource=pypi depName=mergify-cli
-    default: 2026.6.8.1
-  python_version:
-    description: Python version to set up for the install (passed to actions/setup-python).
-    default: "3.14"
+    # renovate: datasource=github-releases depName=Mergifyio/mergify-cli versioning=pep440
+    default: 2026.6.16.1
 outputs:
   mergify_cli_version:
     description: |
-      The mergify-cli version that was installed. Resolved from the installed
-      package metadata, so it reflects the real version even when `latest` or an
-      empty input was requested.
+      The mergify-cli version that was installed. Read back from the installed
+      binary, so it reflects the real version even when `latest` or an empty
+      input was requested.
     value: ${{ steps.install.outputs.mergify_cli_version }}
 runs:
   using: composite
   steps:
-    - name: Setup Python 🔧
-      uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
-      with:
-        python-version: ${{ inputs.python_version }}
-
-    - name: Install uv
-      uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # v8.2.0
-      with:
-        # mergify is too small to benefit + there is no version lock (so no cache key either)
-        enable-cache: false
-
     - name: Install mergify-cli
       id: install
       shell: bash
       env:
         MERGIFY_CLI_VERSION: ${{ inputs.mergify_cli_version }}
       run: |
-        if [ -z "$MERGIFY_CLI_VERSION" ] || [ "$MERGIFY_CLI_VERSION" = "latest" ]; then
-          # --upgrade implies --refresh, so uv re-resolves against PyPI and
-          # installs the newest release even on persistent self-hosted runners
-          # where an older mergify-cli is already cached.
-          uv tool install --upgrade mergify-cli
+        set -euo pipefail
+
+        REPO="Mergifyio/mergify-cli"
+
+        die() { echo "::error::$1" >&2; exit 1; }
+
+        # For a pinned version, fetch the installer from that release tag (its
+        # asset naming matches the binary it installs); for `latest`/empty,
+        # fetch it from `main` and let the installer resolve the latest release.
+        if [ -z "${MERGIFY_CLI_VERSION}" ] || [ "${MERGIFY_CLI_VERSION}" = "latest" ]; then
+          ref="main"
         else
-          uv tool install "mergify-cli==$MERGIFY_CLI_VERSION"
+          ref="${MERGIFY_CLI_VERSION}"
         fi
-        mergify --version
-        # `mergify --version` may print a placeholder while versioning becomes
-        # Rust-native, so read the resolved version from the package metadata.
-        installed=$(uv tool list | awk '/^mergify-cli /{print $2}' | sed 's/^v//')
-        echo "mergify_cli_version=$installed" >> "$GITHUB_OUTPUT"
+
+        bindir="${RUNNER_TEMP}/mergify-cli-bin"
+
+        # Install via the CLI's own installer: it owns platform detection, asset
+        # naming, and SHA256SUMS verification, so we don't duplicate (or have to
+        # track) any of that. MERGIFY_VERSION forwards the requested version; an
+        # empty/`latest` value lets the installer resolve the latest release.
+        # install.sh supports Linux and macOS only.
+        tmp=$(mktemp -d)
+        trap 'rm -rf "${tmp}"' EXIT
+        curl -fsSL "https://raw.githubusercontent.com/${REPO}/${ref}/install.sh" -o "${tmp}/install.sh" \
+          || die "failed to fetch install.sh (ref ${ref})"
+        MERGIFY_VERSION="${MERGIFY_CLI_VERSION}" MERGIFY_INSTALL_DIR="${bindir}" sh "${tmp}/install.sh"
+
+        # Expose the binary to later steps and read the version back from it
+        # (the binary reports its real version) for the action output.
+        echo "${bindir}" >> "${GITHUB_PATH}"
+        installed=$("${bindir}/mergify" --version | awk '{print $NF}')
+        [ -n "${installed}" ] || die "could not read installed mergify-cli version"
+        echo "mergify_cli_version=${installed}" >> "${GITHUB_OUTPUT}"

renovate.json

@@ -11,8 +11,8 @@
   "lockFileMaintenance": { "enabled": true },
   "packageRules": [
     {
-      "matchDatasources": ["pypi"],
-      "matchPackageNames": ["mergify-cli"],
+      "matchDatasources": ["github-releases"],
+      "matchPackageNames": ["Mergifyio/mergify-cli"],
       "minimumReleaseAge": "2 days"
     },
     {
@@ -40,8 +40,9 @@
       "matchStrings": [
         "\\| `mergify_cli_version` \\| string \\| \\w+ \\| `(?<currentValue>[^`]+)` \\|"
       ],
-      "datasourceTemplate": "pypi",
-      "depNameTemplate": "mergify-cli"
+      "datasourceTemplate": "github-releases",
+      "depNameTemplate": "Mergifyio/mergify-cli",
+      "versioningTemplate": "pep440"
     },
     {
       "description": "Bump the self-referenced action version pinned in the README usage example on each new setup-cli release.",