introduce perl-version-file input

.github/workflows/test.yml

@@ -336,6 +336,32 @@ jobs:
           cpanm --help
           cpm --help
 
+  test-version-file:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Set Node.js 16.x
+        uses: actions/setup-node@v3
+        with:
+          node-version: 16.x
+          cache: npm
+
+      - run: npm ci
+      - run: npm run build
+      - run: npm run package
+      - run: echo "5.30.0" > .perl-version
+
+      - id: setup-perl
+        name: use the action
+        uses: ./
+        with:
+          perl-version-file: ".perl-version"
+      - name: show the version
+        run: |
+          perl -V
+
   format:
     runs-on: ubuntu-latest
     steps:

README.md

@@ -99,7 +99,9 @@ The action uses the latest Perl version available that matches the specified val
 This defaults to `5`, which results in the latest available version of Perl 5.
 In addition, the value `latest` is available, the actions uses the latest available version of Perl including `5`, `7` or later major versions.
 
-- Default: `5`
+### `perl-version-file`
+
+Specifies the path to the version file such as `.perl-version`.
 
 ### `distribution`
 

action.yml

@@ -4,7 +4,9 @@ author: "Ichinose Shogo"
 inputs:
   perl-version:
     description: "The Perl version to download (if necessary) and use. Example: 5.30.0"
-    default: "5"
+    required: false
+  perl-version-file:
+    description: "File containing the Perl version. Example: .perl-version"
     required: false
   distribution:
     description: |

src/setup-perl.ts

@@ -3,6 +3,7 @@ import * as exec from "@actions/exec";
 import * as installer from "./installer";
 import * as path from "path";
 import * as crypto from "crypto";
+import * as fs from "fs/promises";
 import * as strawberry from "./strawberry";
 import * as cpan from "./cpan-installer";
 import { getPackagePath, parseBoolean } from "./utils";
@@ -12,7 +13,7 @@ async function run() {
     const platform = process.platform;
     let dist = core.getInput("distribution");
     const multiThread = core.getInput("multi-thread");
-    const version = core.getInput("perl-version");
+    const version = await resolveVersionInput();
 
     let result: installer.Result;
     let perlHash: string;
@@ -95,4 +96,20 @@ async function digestOfPerlVersion(toolPath: string): Promise<string> {
   return hash.digest("hex");
 }
 
+async function resolveVersionInput(): Promise<string> {
+  let version = core.getInput("perl-version");
+  const versionFile = core.getInput("perl-version-file");
+  if (version && versionFile) {
+    core.warning("Both perl-version and perl-version-file inputs are specified, only perl-version will be used");
+  }
+  if (version) {
+    return version;
+  }
+
+  const versionFilePath = path.join(process.env.GITHUB_WORKSPACE || "", versionFile || ".python-version");
+  version = await fs.readFile(versionFilePath, "utf8");
+  core.info(`Resolved ${versionFile} as ${version}`);
+  return version;
+}
+
 run();