Merge pull request gitpython-developers#79 from znerol/feature/master/cmd-output-strip

Add an output_strip kwarg to Git.execute

Author: Byron

git/cmd.py

@@ -19,7 +19,7 @@
 
 execute_kwargs = ('istream', 'with_keep_cwd', 'with_extended_output',
 				  'with_exceptions', 'as_process', 
-				  'output_stream' )
+				  'output_stream', 'output_strip' )
 
 __all__ = ('Git', )
 
@@ -267,6 +267,7 @@ def execute(self, command,
 				with_exceptions=True,
 				as_process=False, 
 				output_stream=None, 
+				output_strip=True,
 				**subprocess_kwargs
 				):
 		"""Handles executing the command on the shell and consumes and returns
@@ -309,6 +310,11 @@ def execute(self, command,
 			This merely is a workaround as data will be copied from the 
 			output pipe to the given output stream directly.
 			
+		:param output_strip:
+			Strip the last line of the output if it is empty (default). Stripping should
+			be disabled whenever it is important that the output is not modified in any
+			way. For example when retrieving patch files using git-diff.
+			
 		:param subprocess_kwargs:
 			Keyword arguments to be passed to subprocess.Popen. Please note that 
 			some of the valid kwargs are already set by this method, the ones you 
@@ -359,7 +365,7 @@ def execute(self, command,
 			if output_stream is None:
 				stdout_value, stderr_value = proc.communicate() 
 				# strip trailing "\n"
-				if stdout_value.endswith("\n"):
+				if stdout_value.endswith("\n") and output_strip:
 					stdout_value = stdout_value[:-1]
 				if stderr_value.endswith("\n"):
 					stderr_value = stderr_value[:-1]

git/test/test_cmd.py

@@ -108,3 +108,25 @@ def test_cmd_override(self):
 		finally:
 			type(self.git).GIT_PYTHON_GIT_EXECUTABLE = prev_cmd
 		#END undo adjustment
+		
+	def test_output_strip(self):
+		import subprocess as sp
+		hexsha = "b2339455342180c7cc1e9bba3e9f181f7baa5167"
+
+		# Verify that a trailing newline is stripped from the output of a git
+		# command.
+		content = self.git.cat_file('blob', hexsha)
+		g = self.git.hash_object(istream=sp.PIPE, as_process=True, stdin=True)
+		g.stdin.write(content)
+		g.stdin.close()
+		newsha = g.stdout.readline().strip()
+		self.assertNotEquals(newsha, hexsha)
+
+		# Verify that output of a git command which ends with an empty
+		# line is not modified when the output_strip flag is cleared.
+		content = self.git.cat_file('blob', hexsha, output_strip=False)
+		g = self.git.hash_object(istream=sp.PIPE, as_process=True, stdin=True)
+		g.stdin.write(content)
+		g.stdin.close()
+		newsha = g.stdout.readline().strip()
+		self.assertEquals(newsha, hexsha)