feat: allow to update existing asdf

lib/setup/index.ts

@@ -1,6 +1,7 @@
 import * as core from "@actions/core";
 import * as exec from "@actions/exec";
 import * as io from "@actions/io";
+import * as fs from "fs";
 import * as os from "os";
 import * as path from "path";
 
@@ -14,15 +15,23 @@ export async function setupAsdf(): Promise<void> {
   core.exportVariable("ASDF_DATA_DIR", asdfDir);
   core.addPath(`${asdfDir}/bin`);
   core.addPath(`${asdfDir}/shims`);
-  core.info(`Cloning asdf into ASDF_DIR: ${asdfDir}`);
   const branch = core.getInput("asdf_branch", { required: true });
-  await exec.exec("git", [
-    "clone",
-    "--depth",
-    "1",
-    "--branch",
-    branch,
-    "https://github.com/asdf-vm/asdf.git",
-    asdfDir,
-  ]);
+  if (fs.existsSync(asdfDir)) {
+    core.info(`Updating asdf on ASDF_DIR: ${asdfDir}`);
+    await exec.exec("git", ["fetch", "--depth", "1"], { cwd: asdfDir });
+    await exec.exec("git", ["checkout", "-B", branch, "origin"], {
+      cwd: asdfDir,
+    });
+  } else {
+    core.info(`Cloning asdf into ASDF_DIR: ${asdfDir}`);
+    await exec.exec("git", [
+      "clone",
+      "--depth",
+      "1",
+      "--branch",
+      branch,
+      "https://github.com/asdf-vm/asdf.git",
+      asdfDir,
+    ]);
+  }
 }