remove: unused code (#2014)

src/commitSha.ts

@@ -326,7 +326,6 @@ interface SHAForPullRequestEvent {
   hasSubmodule: boolean
   gitFetchExtraArgs: string[]
   remoteName: string
-  isFork: boolean
 }
 
 export const getSHAForPullRequestEvent = async ({
@@ -335,8 +334,7 @@ export const getSHAForPullRequestEvent = async ({
   isShallow,
   hasSubmodule,
   gitFetchExtraArgs,
-  remoteName,
-  isFork
+  remoteName
 }: SHAForPullRequestEvent): Promise<DiffResult> => {
   let targetBranch = github.context.payload.pull_request?.base?.ref
   const currentBranch = github.context.payload.pull_request?.head?.ref
@@ -507,18 +505,14 @@ export const getSHAForPullRequestEvent = async ({
         }
       }
     } else {
-      if (github.context.payload.action === 'closed' || isFork) {
-        previousSha = github.context.payload.pull_request?.base?.sha
-      } else {
+      previousSha = github.context.payload.pull_request?.base?.sha
+
+      if (!previousSha) {
         previousSha = await getRemoteBranchHeadSha({
           cwd: workingDirectory,
-          branch: targetBranch,
-          remoteName
+          remoteName,
+          branch: targetBranch
         })
-
-        if (!previousSha) {
-          previousSha = github.context.payload.pull_request?.base?.sha
-        }
       }
 
       if (isShallow) {