Warn on mnc usage (#102)

* Warn on mnc usage

* Only run the warning on MNC on a flag

* Update URL

* phrasing nits

package.json

@@ -27,6 +27,7 @@
   "dependencies": {
     "@actions/core": "^1.11.1",
     "@actions/exec": "^1.1.1",
+    "@actions/glob": "^0.5.0",
     "detsys-ts": "github:DeterminateSystems/detsys-ts",
     "got": "^14.4.5",
     "tail": "^2.2.6"

pnpm-lock.yaml

@@ -11,6 +11,9 @@ dependencies:
   '@actions/exec':
     specifier: ^1.1.1
     version: 1.1.1
+  '@actions/glob':
+    specifier: ^0.5.0
+    version: 0.5.0
   detsys-ts:
     specifier: github:DeterminateSystems/detsys-ts
     version: github.com/DeterminateSystems/detsys-ts/eb87094f35072ac911526ad052c3437c9e0c42d6
@@ -104,6 +107,13 @@ packages:
       minimatch: 3.1.2
     dev: false
 
+  /@actions/glob@0.5.0:
+    resolution: {integrity: sha512-tST2rjPvJLRZLuT9NMUtyBjvj9Yo0MiJS3ow004slMvm8GFM+Zv9HvMJ7HWzfUyJnGrJvDsYkWBaaG3YKXRtCw==}
+    dependencies:
+      '@actions/core': 1.11.1
+      minimatch: 3.1.2
+    dev: false
+
   /@actions/http-client@2.2.3:
     resolution: {integrity: sha512-mx8hyJi/hjFvbPokCg4uRd4ZX78t+YyRPtnKWwIl+RzNaVuFpQHfmlGVfsKEJN8LwTCvL+DfVgAM04XaHkm6bA==}
     dependencies:

src/index.ts

@@ -1,4 +1,5 @@
 import { getTrinaryInput, netrcPath, tailLog } from "./helpers.js";
+import { warnOnMnc } from "./mnc-warn.js";
 import * as actionsCore from "@actions/core";
 import { DetSysAction, inputs, stringifyError } from "detsys-ts";
 import got, { Got, Response } from "got";
@@ -99,6 +100,10 @@ class MagicNixCacheAction extends DetSysAction {
       return;
     }
 
+    if (this.getFeature("warn-magic-nix-cache-eol")?.variant === true) {
+      await warnOnMnc();
+    }
+
     if (this.nixStoreTrust === "untrusted") {
       actionsCore.warning(TEXT_TRUST_UNTRUSTED);
       return;

src/mnc-warn.ts

@@ -0,0 +1,68 @@
+import actionsCore from "@actions/core";
+import glob from "@actions/glob";
+import { stringifyError } from "detsys-ts";
+import * as fs from "node:fs/promises";
+
+export async function warnOnMnc(): Promise<void> {
+  const cwd = process.cwd();
+
+  const patterns = [
+    ".github/actions/*.yaml",
+    ".github/actions/*.yml",
+    ".github/workflows/*.yaml",
+    ".github/workflows/*.yml",
+  ];
+  const globber = await glob.create(patterns.join("\n"));
+  const files = await globber.glob();
+
+  for (const file of files) {
+    try {
+      const relativeFilePath = file.replace(cwd, ".");
+      const lines = (await fs.readFile(file, { encoding: "utf8" })).split("\n");
+
+      for (const lineIdx of lines.keys()) {
+        const line = lines[lineIdx];
+
+        if (
+          line
+            .toLowerCase()
+            .includes("determinatesystems/magic-nix-cache-action")
+        ) {
+          const actionPosition = line
+            .toLowerCase()
+            .indexOf("determinatesystems/magic-nix-cache-action");
+          const actionPositionEnd =
+            actionPosition + "determinatesystems/magic-nix-cache-action".length;
+
+          const newLine = line.replace(
+            /DeterminateSystems\/magic-nix-cache-action/gi,
+            "DeterminateSystems/flakehub-cache-action",
+          );
+          actionsCore.warning(
+            [
+              "Magic Nix Cache has been deprecated due to a change in the underlying GitHub APIs and will stop working on 1 February 2025.",
+              "To continue caching Nix builds in GitHub Actions, use FlakeHub Cache instead.",
+              "",
+              "Replace...",
+              line,
+              "",
+              "...with...",
+              newLine,
+              "",
+              "For more details: https://dtr.mn/magic-nix-cache-eol",
+            ].join("\n"),
+            {
+              title: "Magic Nix Cache is deprecated",
+              file: relativeFilePath,
+              startLine: lineIdx + 1,
+              startColumn: actionPosition,
+              endColumn: actionPositionEnd,
+            },
+          );
+        }
+      }
+    } catch (err) {
+      actionsCore.debug(stringifyError(err));
+    }
+  }
+}