astral-sh · eifinger · Apr 16, 2026 · Apr 16, 2026
@@ -430,6 +430,49 @@ jobs:
          PY
        shell: bash

+  test-activate-environment-no-project:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
+      - name: Create incompatible pyproject.toml
+        run: |
+          cat > pyproject.toml <<'EOF'
+          [project]
+          name = "test-no-project"
+          version = "0.1.0"
+
+          [dependency-groups]
+          dev = [
+              "-e file:///${PROJECT_ROOT}/projects/pkg",
+          ]
+          EOF
+        shell: bash
+      - name: Install latest version with no-project
+        id: setup-uv
+        uses: ./
+        with:
+          python-version: 3.13.1t
+          activate-environment: true
+          no-project: true
+      - name: Verify packages can be installed
+        run: uv pip install pip
+        shell: bash
+      - name: Verify output venv is set
+        run: |
+          if [ -z "$UV_VENV" ]; then
+            echo "output venv is not set"
+            exit 1
+          fi
+          if [ ! -d "$UV_VENV" ]; then
+            echo "output venv not point to a directory: $UV_VENV"
+            exit 1
+          fi
+        shell: bash
+        env:
+          UV_VENV: ${{ steps.setup-uv.outputs.venv }}
+
  test-debian-unstable:
    runs-on: ubuntu-latest
    container: debian:unstable
@@ -1057,6 +1100,7 @@ jobs:
      - test-python-version
      - test-activate-environment
      - test-activate-environment-custom-path
+      - test-activate-environment-no-project
      - test-debian-unstable
      - test-musl
      - test-cache-key-os-version

@@ -62,6 +62,9 @@ Have a look under [Advanced Configuration](#advanced-configuration) for detailed
    # Custom path for the virtual environment when using activate-environment (default: .venv in the working directory)
    venv-path: ""

+    # Pass --no-project when creating the venv with activate-environment.
+    no-project: "false"
+
    # The directory to execute all commands in and look for files such as pyproject.toml
    working-directory: ""


@@ -11,6 +11,8 @@ inputs:
    type: boolean
  venv-path:
    type: string
+  no-project:
+    type: boolean
  working-directory:
    type: string
  checksum:

@@ -18,6 +18,9 @@ inputs:
  venv-path:
    description: "Custom path for the virtual environment when using activate-environment. Defaults to '.venv' in the working directory."
    default: ""
+  no-project:
+    description: "Pass --no-project when creating the venv with activate-environment."
+    default: "false"
  working-directory:
    description: "The directory to execute all commands in and look for files such as pyproject.toml"
    default: ${{ github.workspace }}

@@ -218,13 +218,17 @@ async function activateEnvironment(inputs: SetupInputs): Promise<void> {
    }

    core.info(`Creating and activating python venv at ${inputs.venvPath}...`);
-    await exec.exec("uv", [
+    const venvArgs = [
      "venv",
      inputs.venvPath,
      "--directory",
      inputs.workingDirectory,
      "--clear",
-    ]);
+    ];
+    if (inputs.noProject) {
+      venvArgs.push("--no-project");
+    }
+    await exec.exec("uv", venvArgs);

    let venvBinPath = `${inputs.venvPath}${path.sep}bin`;
    if (process.platform === "win32") {

@@ -22,6 +22,7 @@ export interface SetupInputs {
  versionFile: string;
  pythonVersion: string;
  activateEnvironment: boolean;
+  noProject: boolean;
  venvPath: string;
  checksum: string;
  enableCache: boolean;
@@ -49,6 +50,7 @@ export function loadInputs(): SetupInputs {
  const versionFile = getVersionFile(workingDirectory);
  const pythonVersion = core.getInput("python-version");
  const activateEnvironment = core.getBooleanInput("activate-environment");
+  const noProject = core.getBooleanInput("no-project");
  const venvPath = getVenvPath(workingDirectory, activateEnvironment);
  const checksum = core.getInput("checksum");
  const enableCache = getEnableCache();
@@ -87,6 +89,7 @@ export function loadInputs(): SetupInputs {
    ignoreEmptyWorkdir,
    ignoreNothingToCache,
    manifestFile,
+    noProject,
    pruneCache,
    pythonDir,
    pythonVersion,