From 130b36b699e12aea4a7724d2b3cfc7891e06c0eb Mon Sep 17 00:00:00 2001
From: Moti Zilberman <moti@digital-detox.co.uk>
Date: Wed, 10 May 2017 21:33:20 +0100
Subject: [PATCH] fix(gitUtils): support new repos / unborn branches

This is not tested at the moment due to a mock-git limitation.
---
 .../__snapshots__/index.test.js.snap          |  6 ++---
 src/gitUtils.js                               | 22 +++++++++++++++++--
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/src/__tests__/__snapshots__/index.test.js.snap b/src/__tests__/__snapshots__/index.test.js.snap
index 81b26ac..255217a 100644
--- a/src/__tests__/__snapshots__/index.test.js.snap
+++ b/src/__tests__/__snapshots__/index.test.js.snap
@@ -4,7 +4,7 @@ exports[`git-exec-and-restage no command, no args and no files staged 1`] = `[Er
 
 exports[`git-exec-and-restage with command and arguments, no files 1`] = `
 Array [
-  "git diff-index --cached --name-only --diff-filter=ACDMRTUXB HEAD",
+  "git diff-index --cached --name-only --diff-filter=ACDMRTUXB HEAD --",
   "git diff --name-only --diff-filter=ACDMRTUXB",
   "prettier --write",
 ]
@@ -20,7 +20,7 @@ Array [
 
 exports[`git-exec-and-restage with command+args, files implicit 1`] = `
 Array [
-  "git diff-index --cached --name-only --diff-filter=ACDMRTUXB HEAD",
+  "git diff-index --cached --name-only --diff-filter=ACDMRTUXB HEAD --",
   "git diff --name-only --diff-filter=ACDMRTUXB fullystaged.js partiallystaged.js",
   "prettier --write",
   "git add fullystaged.js",
@@ -53,7 +53,7 @@ Array [
 
 exports[`git-exec-and-restage with command, no args and no files 1`] = `
 Array [
-  "git diff-index --cached --name-only --diff-filter=ACDMRTUXB HEAD",
+  "git diff-index --cached --name-only --diff-filter=ACDMRTUXB HEAD --",
   "git diff --name-only --diff-filter=ACDMRTUXB",
   "prettier",
 ]
diff --git a/src/gitUtils.js b/src/gitUtils.js
index c17bae7..f4cdb92 100644
--- a/src/gitUtils.js
+++ b/src/gitUtils.js
@@ -8,7 +8,9 @@ function ensureRelativePath(s) {
   return s;
 }
 
-async function getAllStaged() {
+const GIT_EMPTY_HASH = "4b825dc642cb6eb9a060e54bf8d69288fbee4904";
+
+async function getAllStagedFromRevision(revision) {
   const diffOut =
     (await spawn(
       "git",
@@ -17,7 +19,8 @@ async function getAllStaged() {
         "--cached",
         "--name-only",
         "--diff-filter=ACDMRTUXB",
-        "HEAD"
+        revision,
+        "--"
       ],
       {
         encoding: "utf8"
@@ -26,6 +29,21 @@ async function getAllStaged() {
   return diffOut.split("\n").filter(s => s !== "");
 }
 
+async function getAllStaged() {
+  try {
+    return await getAllStagedFromRevision("HEAD");
+  } catch (e) {
+    // istanbul ignore else: simple exception passthrough
+    if (
+      e.stderr &&
+      e.stderr.toString().indexOf("fatal: bad revision 'HEAD'") !== -1
+    ) {
+      return await getAllStagedFromRevision(GIT_EMPTY_HASH);
+    }
+    throw e;
+  }
+}
+
 async function getFullyStaged(
   /* istanbul ignore next: convenience default */
   files = []