Install stack if necessary

* Add install-stack input
* Add installed/install functions to StackCLI
* Install stack if necessary
* Build
* Update README
* Skip old LTS on MacOS

.github/workflows/example.yml

@@ -30,6 +30,11 @@ jobs:
           - resolver: lts-12.26
             ghc: "8.4.4"
 
+        exclude:
+          # Binary distributions for older GHCs don't exist on macOS-latest
+          - runner: macOS-latest
+            stack: {ghc: "8.4.4"}
+
       fail-fast: false
 
     runs-on: ${{ matrix.runner }}

README.md

@@ -80,6 +80,7 @@ jobs:
 | `stack-build-arguments-test`         | <p>Additional arguments passed after <code>stack-build-arguments</code> in <code>stack build</code> invocations on the <em>Test</em> step.</p>                                                                                                 | `false`  | `""`                |
 | `cache-prefix`                       | <p>Prefix applied to all cache keys. This can be any value you like, but teams often use <code>v{N}</code> and bump it to <code>v{N+1}</code> when/if they need to explicitly bust caches.</p>                                                 | `false`  | `""`                |
 | `cache-save-always`                  | <p>Save artifacts to the cache even if the build fails. This may speed up builds in subsequent runs at the expense of slightly-longer builds when a full cache-hit occurs. Since <code>@v4.2.0</code>.</p>                                     | `false`  | `false`             |
+| `install-stack`                      | <p>Install stack, if necessary</p>                                                                                                                                                                                                             | `false`  | `true`              |
 | `upgrade-stack`                      | <p>Upgrade stack</p>                                                                                                                                                                                                                           | `false`  | `true`              |
 | `compiler-tools`                     | <p>A list of packages to install as compiler tools, one per line. This is useful to do here rather than separate <code>run</code> commands so that their installation is incorporated in the dependency cache. Since <code>@v5.2.0</code>.</p> | `false`  | `""`                |
 | `stack-yaml`                         | <p><strong>Deprecated</strong> use <code>env.STACK_YAML</code> or <code>stack-arguments</code> instead.</p>                                                                                                                                    | `false`  | `""`                |

action.yml

@@ -48,6 +48,10 @@ inputs:
       builds in subsequent runs at the expense of slightly-longer builds when a
       full cache-hit occurs. Since `@v4.2.0`.
     default: false
+  install-stack:
+    description: |
+      Install stack, if necessary
+    default: true
   upgrade-stack:
     description: |
       Upgrade stack

dist/index.js

@@ -136,6 +136,7 @@ function getInputs() {
         stackBuildArgumentsTest: getBuildArguments("test"),
         cachePrefix: core.getInput("cache-prefix"),
         cacheSaveAlways: core.getBooleanInput("cache-save-always"),
+        installStack: core.getBooleanInput("install-stack"),
         upgradeStack: core.getBooleanInput("upgrade-stack"),
         compilerTools: core.getMultilineInput("compiler-tools"),
         stackYaml: getInputDefault("stack-yaml", null),
@@ -203,18 +204,35 @@ async function run() {
             inputs.stackArguments.unshift("--stack-yaml");
         }
         const stack = new stack_cli_1.StackCLI(inputs.stackArguments, core.isDebug());
+        await core.group("Install/upgrade stack", async () => {
+            const installed = await stack.installed();
+            if (installed) {
+                if (inputs.upgradeStack) {
+                    core.info("Upgrading stack");
+                    await stack.upgrade();
+                }
+            }
+            else {
+                if (inputs.installStack) {
+                    core.info("Installing stack");
+                    await stack.install();
+                }
+                else {
+                    throw new Error([
+                        "The executable stack is not present on $PATH",
+                        "Make sure it is installed in a preceding step, or use",
+                        "`install-stack: true` to have it installed for you.",
+                    ].join("\n"));
+                }
+            }
+        });
         const hashes = await core.group("Calculate hashes", async () => {
             const hashes = await (0, hash_project_1.hashProject)(stack.config);
             core.info(`Snapshot: ${hashes.snapshot}`);
             core.info(`Packages: ${hashes.package}`);
             core.info(`Sources: ${hashes.sources}`);
             return hashes;
         });
-        if (inputs.upgradeStack) {
-            await core.group("Upgrade stack", async () => {
-                await stack.upgrade();
-            });
-        }
         const { stackYaml, stackDirectories } = await core.group("Determine stack directories", async () => {
             const stackYaml = (0, stack_yaml_1.readStackYamlSync)(stack.config);
             const stackDirectories = await (0, stack_yaml_1.getStackDirectories)(stackYaml, stack);
@@ -428,6 +446,20 @@ class StackCLI {
             this.globalArgs.push("nightly");
         }
     }
+    async installed() {
+        const ec = await exec.exec("which", ["stack"], {
+            silent: true,
+            ignoreReturnCode: true,
+        });
+        return ec == 0;
+    }
+    async install() {
+        const url = "https://get.haskellstack.org";
+        const tmp = "install-stack.sh";
+        await exec.exec("curl", ["-sSL", "-o", tmp, url]);
+        await exec.exec("sh", [tmp]);
+        fs.rmSync(tmp);
+    }
     async upgrade() {
         return await exec.exec("stack", ["upgrade"]);
     }

src/inputs.ts

@@ -13,6 +13,7 @@ export type Inputs = {
   stackBuildArgumentsTest: string[];
   cachePrefix: string;
   cacheSaveAlways: boolean;
+  installStack: boolean;
   upgradeStack: boolean;
   compilerTools: string[];
 
@@ -38,6 +39,7 @@ export function getInputs(): Inputs {
     stackBuildArgumentsTest: getBuildArguments("test"),
     cachePrefix: core.getInput("cache-prefix"),
     cacheSaveAlways: core.getBooleanInput("cache-save-always"),
+    installStack: core.getBooleanInput("install-stack"),
     upgradeStack: core.getBooleanInput("upgrade-stack"),
     compilerTools: core.getMultilineInput("compiler-tools"),
     stackYaml: getInputDefault("stack-yaml", null),

src/main.ts

@@ -28,6 +28,30 @@ async function run() {
 
     const stack = new StackCLI(inputs.stackArguments, core.isDebug());
 
+    await core.group("Install/upgrade stack", async () => {
+      const installed = await stack.installed();
+
+      if (installed) {
+        if (inputs.upgradeStack) {
+          core.info("Upgrading stack");
+          await stack.upgrade();
+        }
+      } else {
+        if (inputs.installStack) {
+          core.info("Installing stack");
+          await stack.install();
+        } else {
+          throw new Error(
+            [
+              "The executable stack is not present on $PATH",
+              "Make sure it is installed in a preceding step, or use",
+              "`install-stack: true` to have it installed for you.",
+            ].join("\n"),
+          );
+        }
+      }
+    });
+
     const hashes = await core.group("Calculate hashes", async () => {
       const hashes = await hashProject(stack.config);
       core.info(`Snapshot: ${hashes.snapshot}`);
@@ -36,12 +60,6 @@ async function run() {
       return hashes;
     });
 
-    if (inputs.upgradeStack) {
-      await core.group("Upgrade stack", async () => {
-        await stack.upgrade();
-      });
-    }
-
     const { stackYaml, stackDirectories } = await core.group(
       "Determine stack directories",
       async () => {

src/stack-cli.ts

@@ -48,6 +48,22 @@ export class StackCLI {
     }
   }
 
+  async installed(): Promise<boolean> {
+    const ec = await exec.exec("which", ["stack"], {
+      silent: true,
+      ignoreReturnCode: true,
+    });
+    return ec == 0;
+  }
+
+  async install(): Promise<void> {
+    const url = "https://get.haskellstack.org";
+    const tmp = "install-stack.sh";
+    await exec.exec("curl", ["-sSL", "-o", tmp, url]);
+    await exec.exec("sh", [tmp]);
+    fs.rmSync(tmp);
+  }
+
   async upgrade(): Promise<number> {
     // Avoid this.exec because we don't need/want globalArgs
     return await exec.exec("stack", ["upgrade"]);