From b117bd7366b38061ec91697f9f2c6d1736e01aa4 Mon Sep 17 00:00:00 2001
From: Guanqun Lu <guanqun.lu@gmail.com>
Date: Wed, 4 Sep 2019 23:49:30 +0800
Subject: [PATCH] check git in bootstrap.py when trying to update submodule

---
 src/bootstrap/bootstrap.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/bootstrap/bootstrap.py b/src/bootstrap/bootstrap.py
index 14bc90700b76e..65129eeeec504 100644
--- a/src/bootstrap/bootstrap.py
+++ b/src/bootstrap/bootstrap.py
@@ -708,6 +708,14 @@ def update_submodules(self):
         if (not os.path.exists(os.path.join(self.rust_root, ".git"))) or \
                 self.get_toml('submodules') == "false":
             return
+
+        # check the existence of 'git' command
+        try:
+            subprocess.check_output(['git', '--version'])
+        except (subprocess.CalledProcessError, OSError):
+            print("error: `git` is not found, please make sure it's installed and in the path.")
+            sys.exit(1)
+
         slow_submodules = self.get_toml('fast-submodules') == "false"
         start_time = time()
         if slow_submodules: