Add support for skipping certain files for backporting

Signed-off-by: Kunal Kotwani <[email protected]>

action.yml

@@ -5,6 +5,9 @@ inputs:
   add_labels:
     description: Comma separated list of labels to add to the backport PR.
     required: false
+  files_to_skip:
+    description: Comma seperated list of files to be skipped from the backport
+    required: false
   branch_name:
     description: Custom branch name for the backport PR.
     required: false

src/backport.ts

@@ -94,6 +94,7 @@ const backportOnce = async ({
   owner,
   repo,
   title,
+  filesToSkip,
 }: {
   base: string;
   body: string;
@@ -104,6 +105,7 @@ const backportOnce = async ({
   owner: string;
   repo: string;
   title: string;
+  filesToSkip: string[];
 }) => {
   const git = async (...args: string[]) => {
     await exec("git", args, { cwd: repo });
@@ -112,7 +114,11 @@ const backportOnce = async ({
   await git("switch", base);
   await git("switch", "--create", head);
   try {
-    await git("cherry-pick", "-x", commitToBackport);
+    await git("cherry-pick", "-x", "-n", commitToBackport);
+    if (filesToSkip) {
+      filesToSkip.forEach(file => await git("checkout", "HEAD", file));
+    }
+    await git("commit", "--no-edit", "-s");
   } catch (error: unknown) {
     await git("cherry-pick", "--abort");
     throw error;
@@ -239,13 +245,15 @@ const backport = async ({
   },
   titleTemplate,
   token,
+  filesToSkip,
 }: {
   branchName: string;
   deleteBranch: boolean;
   labelsToAdd: string[];
   payload: EventPayloads.WebhookPayloadPullRequest;
   titleTemplate: string;
   token: string;
+  filesToSkip: string[];
 }) => {
   if (!merged) {
     return;
@@ -310,6 +318,7 @@ const backport = async ({
           owner,
           repo,
           title,
+          filesToSkip,
         });
       } catch (error: unknown) {
         if (!(error instanceof Error)) {

src/get-files-to-skip.ts

@@ -0,0 +1,14 @@
+/**
+ * Get an array of files to be skipped from the backport PR.
+ * Filtering out empty strings.
+ */
+const getFilesToSkip = (input: string | undefined): string[] => {
+  if (input === undefined || input === "") {
+    return [];
+  }
+
+  const files_to_skip = input.split(",");
+  return files_to_skip.map((v) => v.trim()).filter((v) => v !== "");
+};
+
+export { getFilesToSkip };

src/index.ts

@@ -4,6 +4,7 @@ import { EventPayloads } from "@octokit/webhooks";
 
 import { backport } from "./backport";
 import { getLabelsToAdd } from "./get-labels-to-add";
+import { getFilesToSkip } from "./get-files-to-skip";
 
 const run = async () => {
   try {
@@ -14,13 +15,16 @@ const run = async () => {
     debug(JSON.stringify(context, undefined, 2));
     const labelsInput = getInput("add_labels");
     const labelsToAdd = getLabelsToAdd(labelsInput);
+    const filesInput = getInput("files_to_skip");
+    const filesToSkip = getFilesToSkip(labelsInput);
     await backport({
       branchName,
       deleteBranch,
       labelsToAdd,
       payload: context.payload as EventPayloads.WebhookPayloadPullRequest,
       titleTemplate,
       token,
+      filesToSkip
     });
   } catch (error: unknown) {
     if (typeof error !== "string" && !(error instanceof Error)) {