fix: reuse active Vite+ installations for exact versions

.github/workflows/test.yml

@@ -41,6 +41,132 @@ jobs:
       - name: Verify installation
         run: vp --version
 
+  test-reuse-installed-version:
+    # Reproduces https://github.com/voidzero-dev/setup-vp/issues/145. Two setup
+    # steps share an installation, as jobs on a persistent runner would.
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        layout: [home, split]
+        include:
+          - os: ubuntu-latest
+            layout: xdg
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 10
+    env:
+      VP_PR_VERSION: ""
+      REUSE_LAYOUT: ${{ matrix.layout }}
+    steps:
+      - uses: taiki-e/checkout-action@7d1e50e93dc4fb3bba58f85018fadf77898aee8b # v1.4.2
+
+      - name: Prepare project and record CLI downloads
+        shell: bash
+        run: |
+          mkdir -p "$RUNNER_TEMP/reuse-project" "$RUNNER_TEMP/reuse-curl"
+          echo '{"name":"reuse-project","private":true,"devDependencies":{"vite-plus":"0.3.0"}}' > "$RUNNER_TEMP/reuse-project/package.json"
+          reuse_root="$RUNNER_TEMP/setup-vp-reuse"
+          # The Windows installer passes this path to cmd.exe for mklink.
+          if [ "$RUNNER_OS" = "Windows" ]; then reuse_root="$(cygpath -w "$reuse_root")"; fi
+          {
+            case "$REUSE_LAYOUT" in
+              home)
+                echo "VP_HOME=$reuse_root"
+                echo "SETUP_VP_REUSE_DATA=$reuse_root"
+                ;;
+              split)
+                echo "VP_HOME="
+                echo "VP_DATA_DIR=$reuse_root"
+                echo "VP_BIN_DIR=$reuse_root-bin"
+                echo "VP_CACHE_DIR=$reuse_root-cache"
+                echo "SETUP_VP_REUSE_DATA=$reuse_root"
+                ;;
+              xdg)
+                echo "VP_HOME="
+                echo "XDG_DATA_HOME=$reuse_root-xdg"
+                echo "SETUP_VP_REUSE_DATA=$reuse_root-xdg/vite-plus"
+                ;;
+            esac
+            echo "SETUP_VP_REUSE_CURL=$(command -v curl)"
+            echo "SETUP_VP_REUSE_DOWNLOADS=$RUNNER_TEMP/setup-vp-reuse-downloads.log"
+          } >> "$GITHUB_ENV"
+          : > "$RUNNER_TEMP/setup-vp-reuse-downloads.log"
+          cat > "$RUNNER_TEMP/reuse-curl/curl" <<'EOF'
+          #!/bin/bash
+          set -euo pipefail
+          for arg in "$@"; do
+            case "$arg" in
+              */vite-plus-cli-*.tgz)
+                printf '%s\n' "$arg" >> "$SETUP_VP_REUSE_DOWNLOADS"
+                ;;
+            esac
+          done
+          exec "$SETUP_VP_REUSE_CURL" "$@"
+          EOF
+          chmod +x "$RUNNER_TEMP/reuse-curl/curl"
+          echo "$RUNNER_TEMP/reuse-curl" >> "$GITHUB_PATH"
+
+      - name: Setup Vite+ for the first time
+        id: first-setup
+        uses: ./
+        with:
+          working-directory: ${{ runner.temp }}/reuse-project
+          node-version: "22.23.1"
+          run-install: false
+          cache: false
+
+      - name: Check the first installation and start recording reuse
+        shell: bash
+        working-directory: ${{ runner.temp }}/reuse-project
+        env:
+          INSTALLED_VERSION: ${{ steps.first-setup.outputs.version }}
+        run: |
+          test "$INSTALLED_VERSION" = "0.3.0"
+          binary=vp
+          if [ "$RUNNER_OS" = "Windows" ]; then binary=vp.exe; fi
+          test -x "$SETUP_VP_REUSE_DATA/current/bin/$binary"
+          test -f "$SETUP_VP_REUSE_DATA/0.3.0/node_modules/vite-plus/package.json"
+          test "$(node --version)" = "v22.23.1"
+          # Check that the recorder sees real downloads before relying on it.
+          # Windows downloads through PowerShell; install.log covers that path.
+          if [ "$RUNNER_OS" != "Windows" ]; then test -s "$SETUP_VP_REUSE_DOWNLOADS"; fi
+          echo "CLI downloads during the first setup:"
+          cat "$SETUP_VP_REUSE_DOWNLOADS"
+          # The installer truncates this log when it runs its own vp install.
+          python -c 'import os, sys; print(os.stat(sys.argv[1]).st_mtime_ns)' "$SETUP_VP_REUSE_DATA/0.3.0/install.log" > "$RUNNER_TEMP/reuse-install-log-before"
+          : > "$SETUP_VP_REUSE_DOWNLOADS"
+
+      - name: Setup the same Vite+ version again
+        id: second-setup
+        uses: ./
+        with:
+          working-directory: ${{ runner.temp }}/reuse-project
+          node-version: "22.23.1"
+          run-install: false
+          cache: false
+
+      - name: Verify the second setup reuses the installation
+        shell: bash
+        working-directory: ${{ runner.temp }}/reuse-project
+        env:
+          INSTALLED_VERSION: ${{ steps.second-setup.outputs.version }}
+        run: |
+          test "$INSTALLED_VERSION" = "0.3.0"
+          test "$(node --version)" = "v22.23.1"
+          failed=0
+          if [ -s "$SETUP_VP_REUSE_DOWNLOADS" ]; then
+            echo "::error::The second setup downloaded the installed Vite+ version again (issue #145)."
+            cat "$SETUP_VP_REUSE_DOWNLOADS"
+            failed=1
+          fi
+          python -c 'import os, sys; print(os.stat(sys.argv[1]).st_mtime_ns)' "$SETUP_VP_REUSE_DATA/0.3.0/install.log" > "$RUNNER_TEMP/reuse-install-log-after"
+          if ! cmp -s "$RUNNER_TEMP/reuse-install-log-before" "$RUNNER_TEMP/reuse-install-log-after"; then
+            echo "::error::The second setup rewrote install.log by running the wrapper install again (issue #145)."
+            diff -u "$RUNNER_TEMP/reuse-install-log-before" "$RUNNER_TEMP/reuse-install-log-after" || true
+            failed=1
+          fi
+          exit "$failed"
+
   test-preview-build:
     # End-to-end coverage for the commit-pinned install path: resolve the
     # newest pkg.pr.new preview build (0.0.0-commit.<sha>) from the registry

README.md

@@ -374,6 +374,18 @@ Omitting both `node-version` and `node-version-file` leaves the session without
 
 ## Caching
 
+### Reuse an installed version
+
+On runners that retain the Vite+ installation, the GitHub Action reuses an
+active exact version when its files, shims, and Node.js manager configuration
+pass the reuse checks. This applies to versions that support `VP_DUMP_DIRS`
+(`0.3.0` and later). Node.js setup and the remaining action steps still run.
+
+The action runs the installer when it needs to change versions or repair the
+installation. It also runs the installer for dist-tags such as `latest`, version
+ranges, preview builds, and older releases. Reuse works with `cache: false` and
+does not restore an installation onto a fresh runner.
+
 ### Dependency Cache
 
 When `cache: true` is set, the action additionally caches project dependencies by auto-detecting your lock file:

src/install-viteplus.test.ts

@@ -3,6 +3,7 @@ import { exec } from "@actions/exec";
 import { addPath, warning } from "@actions/core";
 import { writeFileSync } from "node:fs";
 import { installVitePlus } from "./install-viteplus.js";
+import { findReusableVitePlus } from "./reuse-viteplus.js";
 import type { Inputs } from "./types.js";
 
 vi.mock("@actions/core", () => ({
@@ -15,6 +16,8 @@ vi.mock("@actions/exec", () => ({
   exec: vi.fn(),
 }));
 
+vi.mock("./reuse-viteplus.js", () => ({ findReusableVitePlus: vi.fn() }));
+
 vi.mock("node:timers/promises", () => ({
   setTimeout: vi.fn().mockResolvedValue(undefined),
 }));
@@ -86,6 +89,17 @@ describe("installVitePlus", () => {
     expect(addPath).toHaveBeenCalledWith("/test/data/bin");
   });
 
+  it("reuses a validated installation and puts it first on PATH", async () => {
+    vi.stubEnv("PATH", "/other/bin:/existing/bin");
+    vi.mocked(findReusableVitePlus).mockReturnValue("/existing/bin");
+
+    await installVitePlus({ ...baseInputs, version: "0.3.0", nodeManager: true });
+
+    expect(findReusableVitePlus).toHaveBeenCalledWith("0.3.0", true);
+    expect(addPath).toHaveBeenCalledWith("/existing/bin");
+    expect(exec).not.toHaveBeenCalled();
+  });
+
   it("should fall back to the legacy bin for Vite+ releases without VpDirs", async () => {
     vi.stubEnv("HOME", "/home/runner");
     vi.stubEnv("PATH", "/usr/bin");

src/install-viteplus.ts

@@ -14,6 +14,7 @@ import {
 import type { Inputs } from "./types.js";
 import { DISPLAY_NAME } from "./types.js";
 import { getVitePlusHome } from "./utils.js";
+import { findReusableVitePlus } from "./reuse-viteplus.js";
 
 // Try each group's URLs in order, for up to N rounds per group (max attempts
 // per group = rounds * URLs). Two rounds × two URLs = 4 attempts, ~1 minute
@@ -24,6 +25,15 @@ const INSTALL_RETRY_DELAY_MS = 2000;
 export async function installVitePlus(inputs: Inputs): Promise<void> {
   const { version } = inputs;
 
+  const existingBin = findReusableVitePlus(version, inputs.nodeManager);
+  if (existingBin) {
+    // Prepend even when already present later on PATH: another installation
+    // must not shadow the version that passed the reuse checks.
+    addPath(existingBin);
+    info(`Reusing ${DISPLAY_NAME}@${version} from ${existingBin}`);
+    return;
+  }
+
   info(`Installing ${DISPLAY_NAME}@${version}...`);
 
   // TODO: Remove VITE_PLUS_VERSION once vite-plus versions before the VP_* env var