add excludeTarget input option

README.md

@@ -72,6 +72,12 @@ You can see more info about GitHub's default token [here](https://docs.github.co
 
 default: `${{ github.token }}`
 
+### `excludeTarget`
+
+When set to `true` excludes commits from the target branch.
+
+default: `false`
+
 ## Outputs
 
 ### `results`

action.yml

@@ -34,6 +34,14 @@ inputs:
       https://docs.github.com/en/actions/configuring-and-managing-workflows/authenticating-with-the-github_token
     default: ${{ github.token }}
     required: false
+  excludeTarget:
+    description: >
+      When set to `true` excludes commits from the target branch. This is useful on merge commits of two
+      divergent branches. By default all of the commits in the target branch that are not in the source
+      branch will be linted again. Set this to `true` to avoid that.
+    default: "false"
+    required: false
+
 outputs:
   results:
     description: The error and warning messages for each one of the analyzed commits

src/action.js

@@ -78,6 +78,10 @@ function getHistoryCommits(from, to) {
     options.firstParent = true
   }
 
+  if (getInput('excludeTarget') === 'true') {
+    options[`^${to}`] = true
+  }
+
   if (!from) {
     options.maxCount = 1
   }