Addition of replace mode to replace existing comments.

README.md

@@ -55,6 +55,10 @@ If the workflow succeeds, the bot comments the details of the preview environmen
     # If a comment with the given id is not found, a new comment is created
     append: true
 
+    # Replaces the message of a comment that already exits with the given id.
+    # If a comment with the given id is not found, a new comment is created
+    replace: true
+
     # Deletes all the existing comments matching the given id and
     # creates a new comment with the given message
     recreate: true
@@ -63,9 +67,7 @@ If the workflow succeeds, the bot comments the details of the preview environmen
     delete: true
 ```
 
-**Note:** The `number` and `commit-sha` fields are mutually exclusive. Only one of them should be set in a job. If both or none are present, an error will be thrown and the job will fail.
-
-**Note**: The `append` and `recreate` fields are also mutually exclusive. If none of them are set, the job will continue in normal mode but if both are present an error will be thrown and the job will fail.
+**Note**: `append`, `recreate`, `replace`, and `delete` fields are mutually exclusive. If more than one of them are set, an error will be thrown and the job will fail.
 
 ## Scenarios
 
@@ -165,6 +167,45 @@ jobs:
           append: true
 ```
 
+### Create a comment and replace an identical comment
+
+This uses the `replace` flag to replace any existing comment created with the same id.
+
+```yml
+on:
+  pull_request:
+    types: [opened]
+
+jobs:
+  deploy-preview:
+    runs-on: ubuntu-20.04
+    name: Deploy preview
+    steps:
+      - name: Notify about starting this deployment
+        uses: hasura/comment-progress@v2.3.0
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          repository: "my-org/my-repo"
+          number: ${{ github.event.number }}
+          id: deploy-preview
+          message: "Starting deployment of this pull request."
+
+      - name: Deploy preview
+        run: |
+          echo "deploy preview"
+          # long running step
+
+      - name: Notify about the result of this deployment
+        uses: hasura/comment-progress@v2.3.0
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          repository: "my-org/my-repo"
+          number: ${{ github.event.number }}
+          id: deploy-preview
+          message: "Deployment of a preview for this pull request was successful."
+          replace: true
+```
+
 ### Delete older/stale comment and add a new comment
 
 Take a case where you need to re-deploy a preview for your pull request and report the status of the redeployment as a new comment and at the same time delete the old comment containing stale information. `recreate` flag will help in achieving this scenario.

action.yml

@@ -28,6 +28,10 @@ inputs:
     description: 'If true, message will be appended to existing comment'
     required: false
     default: false
+  replace:
+    description: 'If true, message will replace existing comment'
+    required: false
+    default: false
   recreate:
     description: 'If true, message will be commented after deleting existing comment'
     required: false