Emit deprecation warnings for derecated inputs

- Adds an upgrade-guide to assist with resolving deprecations
- Emit a warning when deprecated features are used
- List all deprecated features in Job Summary and link to upgrade guide

sources/src/deprecation-collector.ts

@@ -0,0 +1,54 @@
+import * as core from '@actions/core'
+import * as github from '@actions/github'
+
+const DEPRECATION_UPGRADE_PAGE = 'https://github.com/gradle/actions/blob/main/docs/deprecation-upgrade-guide.md'
+const recordedDeprecations: Deprecation[] = []
+
+export class Deprecation {
+    constructor(readonly message: string) {}
+
+    getDocumentationLink(): string {
+        const deprecationAnchor = this.message
+            .toLowerCase()
+            .replace(/[^\w\s-]|_/g, '')
+            .replace(/ /g, '-')
+        return `${DEPRECATION_UPGRADE_PAGE}#${deprecationAnchor}`
+    }
+}
+
+export function recordDeprecation(message: string): void {
+    if (!recordedDeprecations.some(deprecation => deprecation.message === message)) {
+        recordedDeprecations.push(new Deprecation(message))
+    }
+}
+
+export function getDeprecations(): Deprecation[] {
+    return recordedDeprecations
+}
+
+export function emitDeprecationWarnings(): void {
+    if (recordedDeprecations.length > 0) {
+        core.warning(
+            `This job uses deprecated functionality from the '${github.context.action}' action. Consult the Job Summary for more details.`
+        )
+        for (const deprecation of recordedDeprecations) {
+            core.info(`DEPRECATION: ${deprecation.message}. See ${deprecation.getDocumentationLink()}`)
+        }
+    }
+}
+
+export function saveDeprecationState(): void {
+    core.saveState('deprecations', JSON.stringify(recordedDeprecations))
+}
+
+export function restoreDeprecationState(): void {
+    const stringRep = core.getState('deprecations')
+    if (stringRep === '') {
+        return
+    }
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    JSON.parse(stringRep).forEach((obj: any) => {
+        recordedDeprecations.push(new Deprecation(obj.message))
+    })
+}