fixes #1: add branch input and changed-branch output to see remote branch diff (#2)

* change script type
* update control flow to output more information

Author: jeddai

README.md

@@ -20,12 +20,20 @@ URL from which to fetch Nimbus experiments. Default: `https://experimenter.servi
 
 **Required** App name by which to filter experiments. Example: `fenix`
 
+### `branch`
+
+**Required** Remote branch to check diff against. Example: `automation/update-nimbus-experiments`
+
 ## Outputs
 
 ### `changed`
 
 The number of files that were modified as part of the script.
 
+### `changed-branch`
+
+The number of files that were modified as compared to the supplied remote branch.
+
 ## Example usage
 
 ```yaml
@@ -34,4 +42,5 @@ with:
   repo-path: main
   output-path: app/src/main/res/raw/initial_experiments.json
   experimenter-url: https://experimenter.services.mozilla.com/api/v6/experiments/
+  branch: automation/update-nimbus-experiments
 ```

action.yml

@@ -14,14 +14,20 @@ inputs:
   app-name:
     description: 'App name by which to filter experiments'
     required: true
+  branch:
+    description: 'Remote branch to check diff against'
+    required: true
 outputs:
   changed:
     description: 'The number of files that were modified as part of the script'
+  changed-branch:
+    description: 'The number of files that were modified as compared to the supplied remote branch'
 runs:
   using: 'docker'
   image: 'Dockerfile'
   args:
     - ${{ inputs.repo-path }}
     - ${{ inputs.output-path }}
     - ${{ inputs.experimenter-url }}
-    - ${{ inputs.app-name }}
+    - ${{ inputs.app-name }}
+    - ${{ inputs.branch }}

entrypoint.sh

@@ -1,4 +1,4 @@
-#!/bin/sh -l
+#!/bin/bash
 
 git config --global --add safe.directory "/github/workspace/$1"
 
@@ -7,12 +7,30 @@ curl $3 | jq --arg APP_NAME "$4" '{"data":map(select(.appName == $APP_NAME))}' >
 
 git status
 export CHANGED=$(git status -s | wc -l)
+export CHANGED_BRANCH=0
 
 if test $CHANGED -eq 1
 then
-git add $2
-echo "$CHANGED file(s) have been modified"
+    git add $2
+    echo "$CHANGED file(s) have been modified"
+
+    export REMOTE_BRANCH=$(git ls-remote --head origin $5)
+    if [[ -z $REMOTE_BRANCH ]];
+    then
+        export CHANGED_BRANCH=1
+        echo "Remote branch currently does not exist; outputting that there are changes."
+    else
+        export CHANGED_BRANCH=$(git --no-pager diff origin/$5 | grep $2 | wc -l)
+        if test $CHANGED_BRANCH -eq 1
+        then
+            echo "Remote branch differs from current changes, it should be updated."
+        else
+            echo "Remote branch and current changes are equivalent."
+        fi
+    fi
 else
-echo "No changes to make, exiting job"
+    echo "No changes to make, exiting job"
 fi
+
 echo "::set-output name=changed::$CHANGED"
+echo "::set-output name=changed-branch::$CHANGED_BRANCH"