Fix `pull_request_target` event

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

__tests__/meta.test.ts

@@ -648,7 +648,7 @@ describe('push', () => {
         "org.opencontainers.image.revision=90dd6032fac8bda1b6c4436a2e65de27961ed071",
         "org.opencontainers.image.licenses=MIT"
       ]
-      ],
+    ]
   ])('given %p with %p event', tagsLabelsTest);
 });
 
@@ -1840,6 +1840,43 @@ describe('pr', () => {
         "org.opencontainers.image.revision=f24900bfcfee76d8055c8421a164c7e57ad20e68",
         "org.opencontainers.image.licenses=MIT"
       ]
+    ],
+    [
+      'pr09',
+      'event_pull_request_target.env',
+      {
+        images: ['org/app'],
+        tags: [
+          `type=ref,event=tag`,
+          `type=ref,event=pr`,
+          `type=ref,event=branch`,
+          `type=sha`,
+          `type=sha,format=long`
+        ]
+      } as Inputs,
+      {
+        main: 'pr-8',
+        partial: [
+          'sha-f24900b',
+          'sha-f24900bfcfee76d8055c8421a164c7e57ad20e68'
+        ],
+        latest: false
+      } as Version,
+      [
+        'org/app:pr-8',
+        'org/app:sha-f24900b',
+        'org/app:sha-f24900bfcfee76d8055c8421a164c7e57ad20e68'
+      ],
+      [
+        "org.opencontainers.image.title=Hello-World",
+        "org.opencontainers.image.description=This your first repo!",
+        "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
+        "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
+        "org.opencontainers.image.version=pr-8",
+        "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
+        "org.opencontainers.image.revision=f24900bfcfee76d8055c8421a164c7e57ad20e68",
+        "org.opencontainers.image.licenses=MIT"
+      ]
     ]
   ])('given %p with %p event', tagsLabelsTest);
 });

dist/index.js

@@ -382,6 +382,11 @@ const fcl = __importStar(__webpack_require__(3716));
 const core = __importStar(__webpack_require__(2186));
 class Meta {
     constructor(inputs, context, repo) {
+        // Needs to override Git reference with pr ref instead of upstream branch ref
+        // for pull_request_target event
+        if (/pull_request_target/.test(context.eventName)) {
+            context.ref = `refs/pull/${context.payload.number}/merge`;
+        }
         this.inputs = inputs;
         this.context = context;
         this.repo = repo;
@@ -531,14 +536,10 @@ class Meta {
         return Meta.setVersion(version, vraw, this.flavor.latest == 'auto' ? true : this.flavor.latest == 'true');
     }
     procRefPr(version, tag) {
-        let ref = this.context.ref;
+        if (!/^refs\/pull\//.test(this.context.ref)) {
-        if (/pull_request_target/.test(this.context.eventName)) {
-            ref = `refs/pull/${this.context.payload.number}/merge`;
-        }
-        if (!/^refs\/pull\//.test(ref)) {
             return version;
         }
-        const vraw = this.setValue(ref.replace(/^refs\/pull\//g, '').replace(/\/merge$/g, ''), tag);
+        const vraw = this.setValue(this.context.ref.replace(/^refs\/pull\//g, '').replace(/\/merge$/g, ''), tag);
         return Meta.setVersion(version, vraw, this.flavor.latest == 'auto' ? false : this.flavor.latest == 'true');
     }
     procEdge(version, tag) {

src/meta.ts

@@ -27,6 +27,12 @@ export class Meta {
   private readonly date: Date;
 
   constructor(inputs: Inputs, context: Context, repo: ReposGetResponseData) {
+    // Needs to override Git reference with pr ref instead of upstream branch ref
+    // for pull_request_target event
+    if (/pull_request_target/.test(context.eventName)) {
+      context.ref = `refs/pull/${context.payload.number}/merge`;
+    }
+
     this.inputs = inputs;
     this.context = context;
     this.repo = repo;
@@ -191,15 +197,11 @@ export class Meta {
   }
 
   private procRefPr(version: Version, tag: tcl.Tag): Version {
-    let ref = this.context.ref;
+    if (!/^refs\/pull\//.test(this.context.ref)) {
-    if (/pull_request_target/.test(this.context.eventName)) {
-      ref = `refs/pull/${this.context.payload.number}/merge`;
-    }
-    if (!/^refs\/pull\//.test(ref)) {
       return version;
     }
 
-    const vraw = this.setValue(ref.replace(/^refs\/pull\//g, '').replace(/\/merge$/g, ''), tag);
+    const vraw = this.setValue(this.context.ref.replace(/^refs\/pull\//g, '').replace(/\/merge$/g, ''), tag);
     return Meta.setVersion(version, vraw, this.flavor.latest == 'auto' ? false : this.flavor.latest == 'true');
   }