From dd84b9d64fb98746a230cd24233ff50a562c39c9 Mon Sep 17 00:00:00 2001
From: 简律纯 <hsiangnianian@outlook.com>
Date: Fri, 28 Apr 2023 01:36:44 +0800
Subject:

---
 packages/turbo-ignore/src/getComparison.ts | 39 ++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 packages/turbo-ignore/src/getComparison.ts

(limited to 'packages/turbo-ignore/src/getComparison.ts')

diff --git a/packages/turbo-ignore/src/getComparison.ts b/packages/turbo-ignore/src/getComparison.ts
new file mode 100644
index 0000000..a2ad61a
--- /dev/null
+++ b/packages/turbo-ignore/src/getComparison.ts
@@ -0,0 +1,39 @@
+import { info } from "./logger";
+import { TurboIgnoreArgs } from "./types";
+
+export interface GetComparisonArgs extends TurboIgnoreArgs {
+  // the workspace to check for changes
+  workspace: string;
+  // A ref/head to compare against if no previously deployed SHA is available
+  fallback?: string;
+}
+
+export function getComparison(args: GetComparisonArgs): {
+  ref: string;
+  type: "previousDeploy" | "headRelative" | "customFallback";
+} | null {
+  const { fallback, workspace } = args;
+  if (process.env.VERCEL === "1") {
+    if (process.env.VERCEL_GIT_PREVIOUS_SHA) {
+      // use the commit SHA of the last successful deployment for this project / branch
+      info(
+        `Found previous deployment ("${process.env.VERCEL_GIT_PREVIOUS_SHA}") for "${workspace}" on branch "${process.env.VERCEL_GIT_COMMIT_REF}"`
+      );
+      return {
+        ref: process.env.VERCEL_GIT_PREVIOUS_SHA,
+        type: "previousDeploy",
+      };
+    } else {
+      info(
+        `No previous deployments found for "${workspace}" on branch "${process.env.VERCEL_GIT_COMMIT_REF}".`
+      );
+      if (fallback) {
+        info(`Falling back to ref ${fallback}`);
+        return { ref: fallback, type: "customFallback" };
+      }
+
+      return null;
+    }
+  }
+  return { ref: "HEAD^", type: "headRelative" };
+}
-- 
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