From f5f4218cdab046b6f55fdb56043752fbe479d614 Mon Sep 17 00:00:00 2001
From: Thomas Nagy <tnagy@waf.io>
Date: Sun, 10 Dec 2017 21:26:17 +0100
Subject: [PATCH] Set task.stdout=task.stderr for long-running tasks

---
 demos/c/wscript     |  4 +++-
 docs/sphinx/conf.py |  4 ++--
 waflib/Task.py      | 12 ++++++++++++
 waflib/TaskGen.py   | 25 ++++++++++++++++++++++++-
 4 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/demos/c/wscript b/demos/c/wscript
index af5d98e6..b9c8b8a8 100644
--- a/demos/c/wscript
+++ b/demos/c/wscript
@@ -95,7 +95,9 @@ def build(bld):
 		always=True, source='wscript', shell=1, name='Shell')
 	if not Utils.is_win32:
 		bld(rule='echo ${ST:FOO} ${ST:SRC} ${A}${B} ${ST:SRCA} ${ST:SRC[0].abspath()}',
-		always=True, source='wscript', shell=0, cls_keyword=lambda x:'Trying again', name='NoShell')
+			always=True, source='wscript', shell=0,
+			stdout=None, stderr=None,  # disable synchronized outputs on this rule
+			cls_keyword=lambda x:'Trying again', name='NoShell')
 
 	# illustrate how to add a command 'foo' and to execute things in it
 	if bld.cmd == 'foo':
diff --git a/docs/sphinx/conf.py b/docs/sphinx/conf.py
index 51c50e68..2d04da5b 100644
--- a/docs/sphinx/conf.py
+++ b/docs/sphinx/conf.py
@@ -331,7 +331,7 @@ f.close()
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = ['sphinx.ext.autodoc', 'sphinx.ext.todo', 'sphinx.ext.pngmath', 'sphinx.ext.inheritance_diagram', 'sphinx.ext.graphviz', 'sphinx.ext.viewcode']
+extensions = ['sphinx.ext.autodoc', 'sphinx.ext.todo', 'sphinx.ext.imgmath', 'sphinx.ext.inheritance_diagram', 'sphinx.ext.graphviz', 'sphinx.ext.viewcode']
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']
@@ -488,7 +488,7 @@ htmlhelp_basename = 'wafdoc'
 # -- Options for LaTeX output --------------------------------------------------
 
 # The paper size ('letter' or 'a4').
-latex_paper_size = 'a4'
+#latex_paper_size = 'a4'
 
 # The font size ('10pt', '11pt' or '12pt').
 #latex_font_size = '10pt'
diff --git a/waflib/Task.py b/waflib/Task.py
index b2e96129..411caf75 100644
--- a/waflib/Task.py
+++ b/waflib/Task.py
@@ -259,6 +259,13 @@ class Task(evil):
 		:type cmd: list of string (best) or string (process will use a shell)
 		:return: the return code
 		:rtype: int
+
+		Optional parameters:
+
+		#. cwd: current working directory (Node or string)
+		#. stdout: set to None to prevent waf from capturing the process standard output
+		#. stderr: set to None to prevent waf from capturing the process standard error
+		#. timeout: timeout value (Python 3)
 		"""
 		if not 'cwd' in kw:
 			kw['cwd'] = self.get_cwd()
@@ -270,6 +277,11 @@ class Task(evil):
 			env = kw['env'] = dict(kw.get('env') or self.env.env or os.environ)
 			env['PATH'] = self.env.PATH if isinstance(self.env.PATH, str) else os.pathsep.join(self.env.PATH)
 
+		if hasattr(self, 'stdout'):
+			kw['stdout'] = self.stdout
+		if hasattr(self, 'stderr'):
+			kw['stderr'] = self.stderr
+
 		# workaround for command line length limit:
 		# http://support.microsoft.com/kb/830473
 		if not isinstance(cmd, str) and (len(repr(cmd)) >= 8192 if Utils.is_win32 else len(cmd) > 200000):
diff --git a/waflib/TaskGen.py b/waflib/TaskGen.py
index 2e67784b..eb3624fd 100644
--- a/waflib/TaskGen.py
+++ b/waflib/TaskGen.py
@@ -553,6 +553,24 @@ def process_rule(self):
 
 		def build(bld):
 			bld(rule='cp ${SRC} ${TGT}', source='wscript', target='bar.txt')
+
+	Main attributes processed:
+
+	* rule: command to execute, it can be a tuple of strings for multiple commands
+	* chmod: permissions for the resulting files (integer value such as Utils.O755)
+	* shell: set to False to execute the command directly (default is True to use a shell)
+	* scan: scanner function
+	* vars: list of variables to trigger rebuilts, such as CFLAGS
+	* cls_str: string to display when executing the task
+	* cls_keyword: label to display when executing the task
+	* cache_rule: by default, try to re-use similar classes, set to False to disable
+	* source: list of Node or string objects representing the source files required by this task
+	* target: list of Node or string objects representing the files that this task creates
+	* cwd: current working directory (Node or string)
+	* stdout: standard output, set to None to prevent waf from capturing the text
+	* stderr: standard error, set to None to prevent waf from capturing the text
+	* timeout: timeout for command execution (Python 3)
+	* always: whether to always run the command (False by default)
 	"""
 	if not getattr(self, 'rule', None):
 		return
@@ -630,6 +648,12 @@ def process_rule(self):
 	for x in ('after', 'before', 'ext_in', 'ext_out'):
 		setattr(tsk, x, getattr(self, x, []))
 
+	if hasattr(self, 'stdout'):
+		tsk.stdout = self.stdout
+
+	if hasattr(self, 'stderr'):
+		tsk.stderr = self.stderr
+
 	if getattr(self, 'timeout', None):
 		tsk.timeout = self.timeout
 
@@ -665,7 +689,6 @@ def process_rule(self):
 		# methods during instance attribute look-up."
 		tsk.run = functools.partial(tsk.run, tsk)
 
-
 @feature('seq')
 def sequence_order(self):
 	"""