fix: take the pull request SHAs from the event payload

dist/index.js

@@ -30274,9 +30274,13 @@ function decodeDiff(data) {
     }
     throw new Error(`The pull request diff was returned as ${typeof data} rather than text, so no issue can be matched against the pull request`);
 }
-async function getPrDiff(githubToken, owner, repo, prNumber) {
+async function getPrDiff(githubToken, owner, repo) {
     const octokit = (0, github_1.getOctokit)(githubToken);
-    const { base, head } = (await octokit.rest.pulls.get({ owner, repo, pull_number: prNumber })).data;
+    const pr = github_1.context.payload.pull_request;
+    if (pr == null) {
+        throw new Error('No pull request payload found.');
+    }
+    const { base, head } = pr;
     return decodeDiff((await octokit.rest.repos.compareCommits({ owner, repo, base: base.sha, head: head.sha, mediaType: { format: 'diff' } })).data);
 }
 function parseDiffLines(diff) {
@@ -32338,7 +32342,7 @@ async function run() {
             if (prNumber == null) {
                 throw new Error('No pull request number found.');
             }
-            pullRequest ??= [prNumber, await (0, bugalint_1.getPrDiff)(githubToken, github_1.context.repo.owner, github_1.context.repo.repo, prNumber)];
+            pullRequest ??= [prNumber, await (0, bugalint_1.getPrDiff)(githubToken, github_1.context.repo.owner, github_1.context.repo.repo)];
             return pullRequest;
         };
         let issues = [...parser(input)];

src/bugalint.ts

@@ -1,5 +1,5 @@
 import type { Log, Region, ReportingDescriptor, Result } from 'sarif'
-import { getOctokit } from '@actions/github'
+import { context, getOctokit } from '@actions/github'
 import { debug, warning, summary } from '@actions/core'
 import path from 'path'
 import parseDiff from 'parse-diff'
@@ -387,9 +387,13 @@ function decodeDiff(data: unknown): string {
   throw new Error(`The pull request diff was returned as ${typeof data} rather than text, so no issue can be matched against the pull request`)
 }
 
-export async function getPrDiff(githubToken: string, owner: string, repo: string, prNumber: number): Promise<string> {
+export async function getPrDiff(githubToken: string, owner: string, repo: string): Promise<string> {
   const octokit = getOctokit(githubToken)
-  const { base, head } = (await octokit.rest.pulls.get({ owner, repo, pull_number: prNumber })).data
+  const pr = context.payload.pull_request as ({ base: { sha: string } } & { head: { sha: string } }) | undefined
+  if (pr == null) {
+    throw new Error('No pull request payload found.')
+  }
+  const { base, head } = pr
   return decodeDiff((await octokit.rest.repos.compareCommits({ owner, repo, base: base.sha, head: head.sha, mediaType: { format: 'diff' } })).data)
 }
 

src/index.ts

@@ -48,7 +48,7 @@ export async function run(): Promise<void> {
       if (prNumber == null) {
         throw new Error('No pull request number found.')
       }
-      pullRequest ??= [prNumber, await getPrDiff(githubToken, context.repo.owner, context.repo.repo, prNumber)]
+      pullRequest ??= [prNumber, await getPrDiff(githubToken, context.repo.owner, context.repo.repo)]
       return pullRequest
     }