From ca145aa8ab357bbc4db61f064d76bdc02f3f7f45 Mon Sep 17 00:00:00 2001
From: Rahul Gupta <ragupta4@cisco.com>
Date: Wed, 26 Jul 2017 15:22:37 +0530
Subject: [PATCH] adds pre-commit hook support

---
 git-hooks.sh                  | 26 ++++++++++++++++++++++++++
 hooks/check_ast.py            |  1 +
 hooks/check_flake8.py         |  1 -
 hooks/check_merge_conflict.py |  2 ++
 hooks/pre-commit.py           | 33 +++++++++++++++++++++++++++++++++
 hooks/util.py                 | 26 ++++++++++++++++++++------
 6 files changed, 82 insertions(+), 7 deletions(-)
 create mode 100755 git-hooks.sh
 create mode 100755 hooks/pre-commit.py

diff --git a/git-hooks.sh b/git-hooks.sh
new file mode 100755
index 0000000..a59902d
--- /dev/null
+++ b/git-hooks.sh
@@ -0,0 +1,26 @@
+#!/bin/sh
+
+echo "Configuring pre-commit hook..."
+
+# make a symbolic link with the pre-commit hook
+if [ ! -f ./git/hooks/check_flake8.py ]; then
+  ln hooks/check_flake8.py .git/hooks/check_flake8.py
+fi
+if [ ! -f ./git/hooks/check_ast.py ]; then
+  ln hooks/check_ast.py .git/hooks/check_ast.py
+fi
+if [ ! -f ./git/hooks/check_merge_conflict.py ]; then
+  ln hooks/check_merge_conflict.py .git/hooks/check_merge_conflict.py
+fi
+if [ ! -f ./git/hooks/util.py ]; then
+  ln hooks/util.py .git/hooks/util.py
+fi
+
+if [ ! -f ./git/hooks/pre-commit ]; then
+  ln hooks/pre-commit.py .git/hooks/pre-commit
+  echo "Done"
+else
+  cat <<EOF
+A pre-commit hook exists already.
+EOF
+fi
diff --git a/hooks/check_ast.py b/hooks/check_ast.py
index d7303aa..4700835 100755
--- a/hooks/check_ast.py
+++ b/hooks/check_ast.py
@@ -23,6 +23,7 @@ def check_ast(argv=None):
         try:
             ast.parse(open(filename, 'rb').read(), filename=filename)
         except SyntaxError:
+            print("***** ast check failed *****")
             print('{}: failed parsing with {} {}:'.format(
                 filename,
                 platform.python_implementation(),
diff --git a/hooks/check_flake8.py b/hooks/check_flake8.py
index 435f4c1..d591723 100755
--- a/hooks/check_flake8.py
+++ b/hooks/check_flake8.py
@@ -24,7 +24,6 @@ def check_flake8(argv=None):
         sys.exit(1)
 
     files = added_files()
-
     retval = 0
     for filename in files:
         try:
diff --git a/hooks/check_merge_conflict.py b/hooks/check_merge_conflict.py
index 952f1f9..e5d280b 100755
--- a/hooks/check_merge_conflict.py
+++ b/hooks/check_merge_conflict.py
@@ -40,6 +40,8 @@ def detect_merge_conflict(argv=None):
             for i, line in enumerate(inputfile):
                 for pattern in CONFLICT_PATTERNS:
                     if line.startswith(pattern):
+                        if retcode == 0:
+                            print("***** merge conflict check failed *****")
                         print(WARNING_MSG.format(
                             pattern.decode(), filename, i + 1,
                         ))
diff --git a/hooks/pre-commit.py b/hooks/pre-commit.py
new file mode 100755
index 0000000..b998972
--- /dev/null
+++ b/hooks/pre-commit.py
@@ -0,0 +1,33 @@
+#!/usr/bin/env python
+
+import sys
+
+from check_ast import check_ast
+from check_flake8 import check_flake8
+from check_merge_conflict import detect_merge_conflict
+
+def main(argv=None):
+    rc = 0
+    try:
+        check_flake8()
+    except:
+        rc = 1
+
+    try:
+        check_ast()
+    except:
+        rc = 1
+
+    try:
+        detect_merge_conflict()
+    except:
+        rc = 1
+
+    return rc
+
+
+if __name__ == '__main__':
+    exit(main())
+
+
+
diff --git a/hooks/util.py b/hooks/util.py
index f962031..f124fbe 100644
--- a/hooks/util.py
+++ b/hooks/util.py
@@ -7,20 +7,18 @@
 from __future__ import unicode_literals
 
 import subprocess
+import os
+
+devnull = open(os.devnull, 'w')
 
 
 class CalledProcessError(RuntimeError):
     pass
 
 
-def exists(cmd):
-    out, err, rc = cmd_output('which', '%s' % cmd)
-    return rc == 0
-
-
 def added_files():
     out, err, rc = cmd_output('git', 'diff', '--staged', '--name-only')
-    return set(out.splitlines())
+    return set([f for f in out.splitlines() if f.endswith('py')])
 
 
 def cmd_output(*cmd, **kwargs):
@@ -35,3 +33,19 @@ def cmd_output(*cmd, **kwargs):
     if retcode is not None and proc.returncode != retcode:
         raise CalledProcessError(cmd, retcode, proc.returncode, stdout, stderr)
     return stdout, stderr, proc.returncode
+
+
+def execute(cmd, silent=False):
+    if silent:
+        params = {
+                'stdout': devnull,
+                'stderr': devnull,
+                }
+    else:
+        params = {}
+    retcode = subprocess.call(cmd.split(), **params)
+    return retcode
+
+
+def exists(cmd):
+    return execute('which %s' % cmd, silent=True) == 0