feat: support new remote branch creation

README.md

@@ -31,6 +31,10 @@ Add a step like this to your workflow:
     # Default: the branch that triggered the run
     branch: some-branch
 
+    # How the action should behave when the targeted branch is missing: "create" will create a new one on the remote, "throw" will exit
+    # Default: throw
+    branch_mode: create
+
     # The name of the custom committer you want to use, if different from the author of the commit.
     # Default: the name of the author (set with either author_name or default_author)
     committer_name: Committer Name

action.yml

@@ -15,6 +15,10 @@ inputs:
   branch:
     description: Name of the branch to use, if different from the one that triggered the workflow
     required: false
+  branch_mode:
+    description: How the action should behave when the targeted branch is missing
+    required: false
+    default: throw
   committer_name:
     description: The name of the custom committer you want to use
     required: false 

src/main.ts

@@ -20,7 +20,7 @@ const exitErrors: Error[] = []
 
 core.info(`Running in ${baseDir}`)
 ;(async () => {
-  await checkInputs().catch(core.setFailed)
+  await checkInputs()
 
   core.startGroup('Internal logs')
   core.info('> Staging files...')
@@ -57,13 +57,30 @@ core.info(`Running in ${baseDir}`)
     await git.fetch(['--tags', '--force'], log)
 
     core.info('> Switching/creating branch...')
+    /** This should store whether the branch already existed, of if a new one was created */
+    let branchType!: 'existing' | 'new'
     await git
-      .checkout(getInput('branch'), undefined, log)
-      .catch(() => git.checkoutLocalBranch(getInput('branch'), log))
-
-    // The current default value is set here.
-    // When the depreacted pull_strategy input is removed, the default should be set via the action manifest.
-    const pull = getInput('pull') || getInput('pull_strategy') || '--no-rebase'
+      .checkout(getInput('branch'))
+      .then(() => (branchType = 'existing'))
+      .catch(() => {
+        if (getInput('branch_mode') == 'create') {
+          log(
+            undefined,
+            `'${getInput('branch')}' branch not found, trying to create one.`
+          )
+          branchType = 'new'
+          return git.checkoutLocalBranch(getInput('branch'), log)
+        } else throw `'${getInput('branch')}' branch not found.`
+      })
+
+    /* 
+      The current default value is set here: it will not pull when it has 
+      created a new branch, it will use --rebase when the branch already existed 
+    */
+    const pull =
+      getInput('pull') ||
+      getInput('pull_strategy') ||
+      (branchType == 'new' ? 'NO-PULL' : '--no-rebase')
     if (pull == 'NO-PULL') core.info('> Not pulling from repo.')
     else {
       core.info('> Pulling from remote...')
@@ -338,6 +355,18 @@ async function checkInputs() {
     core.info(`> Running for a PR, the action will use '${branch}' as ref.`)
   // #endregion
 
+  // #region branch_mode
+  const branch_mode_valid = ['throw', 'create']
+  if (!branch_mode_valid.includes(getInput('branch_mode')))
+    throw new Error(
+      `"${getInput(
+        'branch_mode'
+      )}" is not a valid value for the 'branch_mode' input. Valid values are: ${branch_mode_valid.join(
+        ', '
+      )}`
+    )
+  // #endregion
+
   // #region pathspec_error_handling
   const peh_valid = ['ignore', 'exitImmediately', 'exitAtEnd']
   if (!peh_valid.includes(getInput('pathspec_error_handling')))

src/util.ts

@@ -8,6 +8,7 @@ interface InputTypes {
   author_name: string
   author_email: string
   branch: string
+  branch_mode: 'throw' | 'create'
   committer_name: string
   committer_email: string
   cwd: string