v8: allow incomplete SHA for backports

Author: targos

lib/update-v8/backport.js

@@ -30,15 +30,15 @@ exports.commitBackport = function commitBackport() {
   return {
     title: 'Commit patch',
     task: async(ctx) => {
-      const messageTitle = `deps: cherry-pick ${ctx.sha.substring(
+      const messageTitle = `deps: cherry-pick ${ctx.fullSha.substring(
         0,
         7
       )} from upstream V8`;
       const indentedMessage = ctx.message.replace(/\n/g, '\n    ');
       const messageBody =
         'Original commit message:\n\n' +
         `    ${indentedMessage}\n\n` +
-        `Refs: https://github.com/v8/v8/commit/${ctx.sha}`;
+        `Refs: https://github.com/v8/v8/commit/${ctx.fullSha}`;
 
       await ctx.execGitNode('add', 'deps/v8');
       await ctx.execGitNode('commit', '-m', messageTitle, '-m', messageBody);
@@ -51,15 +51,11 @@ function generatePatch() {
     title: 'Generate patch',
     task: async(ctx) => {
       const sha = ctx.sha;
-      if (!sha || sha.length !== 40) {
-        throw new Error(
-          '--sha option is required and must be 40 characters long'
-        );
-      }
+      const fullSha = ctx.fullSha = await ctx.execGitV8('rev-parse', sha);
       try {
         const [patch, message] = await Promise.all([
-          ctx.execGitV8('format-patch', '--stdout', `${sha}^..${sha}`),
-          ctx.execGitV8('log', '--format=%B', '-n', '1', sha)
+          ctx.execGitV8('format-patch', '--stdout', `${fullSha}^..${fullSha}`),
+          ctx.execGitV8('log', '--format=%B', '-n', '1', fullSha)
         ]);
         ctx.patch = patch.stdout;
         ctx.message = message.stdout;