perf: set diff quiet and switch isdirty command order

src/create-or-update-branch.ts

@@ -78,15 +78,6 @@ async function isEven(
   )
 }
 
-async function hasDiff(
-  git: GitCommandManager,
-  branch1: string,
-  branch2: string
-): Promise<boolean> {
-  const result = await git.diff([`${branch1}..${branch2}`])
-  return result.length > 0
-}
-
 function splitLines(multilineString: string): string[] {
   return multilineString
     .split('\n')
@@ -205,7 +196,7 @@ export async function createOrUpdateBranch(
     //   to have a diff with the base due to different commits for the same changes.
     // For changes on base this reset is equivalent to a rebase of the pull request branch.
     if (
-      (await hasDiff(git, branch, tempBranch)) ||
+      (await git.hasDiff([`${branch}..${tempBranch}`])) ||
       !(await isAhead(git, base, tempBranch))
     ) {
       core.info(`Resetting '${branch}'`)

src/git-command-manager.ts

@@ -96,15 +96,6 @@ export class GitCommandManager {
     return output.exitCode === 0
   }
 
-  async diff(options?: string[]): Promise<string> {
-    const args = ['-c', 'core.pager=cat', 'diff']
-    if (options) {
-      args.push(...options)
-    }
-    const output = await this.exec(args)
-    return output.stdout.trim()
-  }
-
   async fetch(
     refSpec: string[],
     remoteName?: string,
@@ -153,18 +144,26 @@ export class GitCommandManager {
     return this.workingDirectory
   }
 
+  async hasDiff(options?: string[]): Promise<boolean> {
+    const args = ['diff', '--quiet']
+    if (options) {
+      args.push(...options)
+    }
+    const output = await this.exec(args, true)
+    return output.exitCode === 1
+  }
+
   async isDirty(untracked: boolean): Promise<boolean> {
-    const diffArgs = ['--abbrev=40', '--full-index', '--raw']
-    // Check staged changes
-    if (await this.diff([...diffArgs, '--staged'])) {
+    // Check untracked changes
+    if (untracked && (await this.status(['--porcelain', '-unormal']))) {
       return true
     }
     // Check working index changes
-    if (await this.diff(diffArgs)) {
+    if (await this.hasDiff()) {
       return true
     }
-    // Check untracked changes
-    if (untracked && (await this.status(['--porcelain', '-unormal']))) {
+    // Check staged changes
+    if (await this.hasDiff(['--staged'])) {
       return true
     }
     return false