diff --git a/build_system_kit/makefile_dumper/wscript b/build_system_kit/makefile_dumper/wscript
index 5e9b3f24..4a90fbbe 100644
--- a/build_system_kit/makefile_dumper/wscript
+++ b/build_system_kit/makefile_dumper/wscript
@@ -73,7 +73,7 @@ def dump(bld):
 	def output_makefile(self):
 		self.commands.insert(0, "all: %s" % " ".join(self.targets))
 		node = self.bldnode.make_node('Makefile')
-		node.write("\n".join(self.commands))
-		Logs.warn('Wrote %s' % node.abspath())
+		node.write('\n'.join(self.commands))
+		Logs.warn('Wrote %r', node)
 	bld.add_post_fun(output_makefile)
 
diff --git a/demos/wscript b/demos/wscript
index 2e898da1..2b6baa80 100644
--- a/demos/wscript
+++ b/demos/wscript
@@ -67,7 +67,7 @@ def configure(conf):
 			conf.env.revert()
 			node = conf.path.find_node('%s/build/config.log' % d.name)
 			if node:
-				Logs.info("-- BEGIN %s config.log --\n%s-- END %s config.log --" % (d.name, node.read(), d.name))
+				Logs.info('-- BEGIN %s config.log --\n%s-- END %s config.log --', d.name, node.read(), d.name)
 			try:
 				e = sys.exc_info()[1]
 				print(e)
@@ -92,7 +92,7 @@ def configure(conf):
 		else:
 			conf.env.append_value('PYTHONS', x)
 
-	Logs.info("executing the build for folders %r and with pythons %r" % (conf.env.CFG, conf.env.PYTHONS))
+	Logs.info('executing the build for folders %r and with pythons %r', conf.env.CFG, conf.env.PYTHONS)
 	Logs.info("contents of config.log:")
 	Logs.info(conf.path.find_node('build/config.log').read())
 
diff --git a/docs/book/development.txt b/docs/book/development.txt
index 3ca8f0b6..30d47649 100644
--- a/docs/book/development.txt
+++ b/docs/book/development.txt
@@ -38,7 +38,7 @@ The Waf module 'Logs' replaces the Python module logging. In the source code, tr
 
 [source,python]
 ---------------
-Logs.debug("task: executing %r - it was never run before or its class changed" % self)
+Logs.debug('task: executing %r - it was never run before or its class changed', self)
 ---------------
 
 The following zones are used in Waf:
diff --git a/playground/gtest/wscript b/playground/gtest/wscript
index 5919f3ca..3e6f8cdd 100644
--- a/playground/gtest/wscript
+++ b/playground/gtest/wscript
@@ -42,12 +42,12 @@ def gtest_results(bld):
                 if '    OK ]' in output[i]:
                     continue
                 while not '[ ' in output[i]:
-                    Logs.warn('%s' % output[i])
+                    Logs.warn(output[i])
                     i += 1
             elif ' FAILED  ]' in line and code:
-                Logs.error('%s' % line)
+                Logs.error(line)
             elif ' PASSED  ]' in line:
-                Logs.info('%s' % line)
+                Logs.info(line)
 
 def build(bld):
     bld.recurse('src tests')
diff --git a/playground/implicit_order/wscript b/playground/implicit_order/wscript
index 925d9047..e72b5fc2 100644
--- a/playground/implicit_order/wscript
+++ b/playground/implicit_order/wscript
@@ -57,7 +57,7 @@ def are_implicit_nodes_ready(self):
 	if modified:
 		for tsk in self.run_after:
 			if not tsk.hasrun:
-				Logs.warn("task %r is not ready..." % self)
+				Logs.warn('task %r is not ready...', self)
 				raise Errors.TaskNotReady('not ready')
 Task.Task.are_implicit_nodes_ready = are_implicit_nodes_ready
 
diff --git a/waflib/Build.py b/waflib/Build.py
index 26209684..7218807e 100644
--- a/waflib/Build.py
+++ b/waflib/Build.py
@@ -250,7 +250,7 @@ class BuildContext(Context.Context):
 		* calling :py:meth:`waflib.Build.BuildContext.post_build` to call user build functions
 		"""
 
-		Logs.info("Waf: Entering directory `%s'" % self.variant_dir)
+		Logs.info("Waf: Entering directory `%s'", self.variant_dir)
 		self.recurse([self.run_dir])
 		self.pre_build()
 
@@ -264,7 +264,7 @@ class BuildContext(Context.Context):
 				c = self.producer.processed or 1
 				m = self.progress_line(c, c, Logs.colors.BLUE, Logs.colors.NORMAL)
 				Logs.info(m, extra={'stream': sys.stderr, 'c1': Logs.colors.cursor_off, 'c2' : Logs.colors.cursor_on})
-			Logs.info("Waf: Leaving directory `%s'" % self.variant_dir)
+			Logs.info("Waf: Leaving directory `%s'", self.variant_dir)
 		try:
 			self.producer.bld = None
 			del self.producer
@@ -630,7 +630,7 @@ class BuildContext(Context.Context):
 		#if self.groups and not self.groups[0].tasks:
 		#	error('add_group: an empty group is already present')
 		if name and name in self.group_names:
-			Logs.error('add_group: name %s already present' % name)
+			Logs.error('add_group: name %s already present', name)
 		g = []
 		self.group_names[name] = g
 		self.groups.append(g)
@@ -731,7 +731,7 @@ class BuildContext(Context.Context):
 				Logs.warn('Building from the build directory, forcing --targets=*')
 				ln = self.srcnode
 			elif not ln.is_child_of(self.srcnode):
-				Logs.warn('CWD %s is not under %s, forcing --targets=* (run distclean?)' % (ln.abspath(), self.srcnode.abspath()))
+				Logs.warn('CWD %s is not under %s, forcing --targets=* (run distclean?)', ln.abspath(), self.srcnode.abspath())
 				ln = self.srcnode
 			for tg in self.groups[self.cur]:
 				try:
@@ -1054,11 +1054,11 @@ class inst(Task.Task):
 				# same size and identical timestamps -> make no copy
 				if st1.st_mtime + 2 >= st2.st_mtime and st1.st_size == st2.st_size:
 					if not self.generator.bld.progress_bar:
-						Logs.info('- install %s (from %s)' % (tgt, lbl))
+						Logs.info('- install %s (from %s)', tgt, lbl)
 					return False
 
 		if not self.generator.bld.progress_bar:
-			Logs.info('+ install %s (from %s)' % (tgt, lbl))
+			Logs.info('+ install %s (from %s)', tgt, lbl)
 
 		# Give best attempt at making destination overwritable,
 		# like the 'install' utility used by 'make install' does.
@@ -1077,7 +1077,7 @@ class inst(Task.Task):
 			self.copy_fun(src, tgt)
 		except IOError:
 			if not src.exists():
-				Logs.error('File %r does not exist' % src)
+				Logs.error('File %r does not exist', src)
 			raise Errors.WafError('Could not install the file %r' % tgt)
 
 	def do_link(self, src, tgt, **kw):
@@ -1091,19 +1091,19 @@ class inst(Task.Task):
 		"""
 		if os.path.islink(tgt) and os.readlink(tgt) == src:
 			if not self.generator.bld.progress_bar:
-				Logs.info('- symlink %s (to %s)' % (tgt, src))
+				Logs.info('- symlink %s (to %s)', tgt, src)
 		else:
 			try:
 				os.remove(tgt)
 			except OSError:
 				pass
 			if not self.generator.bld.progress_bar:
-				Logs.info('+ symlink %s (to %s)' % (tgt, src))
+				Logs.info('+ symlink %s (to %s)', tgt, src)
 			os.symlink(src, tgt)
 
 	def do_uninstall(self, src, tgt, lbl, **kw):
 		if not self.generator.bld.progress_bar:
-			Logs.info('- remove %s' % tgt)
+			Logs.info('- remove %s', tgt)
 
 		#self.uninstall.append(tgt)
 		try:
@@ -1114,14 +1114,14 @@ class inst(Task.Task):
 					self.uninstall_error = True
 					Logs.warn('build: some files could not be uninstalled (retry with -vv to list them)')
 				if Logs.verbose > 1:
-					Logs.warn('Could not remove %s (error code %r)' % (e.filename, e.errno))
+					Logs.warn('Could not remove %s (error code %r)', e.filename, e.errno)
 		self.rm_empty_dirs(tgt)
 
 	def do_unlink(self, src, tgt, **kw):
 		# TODO do_uninstall with proper amount of args
 		try:
 			if not self.generator.bld.progress_bar:
-				Logs.info('- remove %s' % tgt)
+				Logs.info('- remove %s', tgt)
 			os.remove(tgt)
 		except OSError:
 			pass
@@ -1289,7 +1289,7 @@ class StepContext(BuildContext):
 								break
 						if do_exec:
 							ret = tsk.run()
-							Logs.info('%s -> exit %r' % (str(tsk), ret))
+							Logs.info('%s -> exit %r', tsk, ret)
 
 	def get_matcher(self, pat):
 		# this returns a function
diff --git a/waflib/Logs.py b/waflib/Logs.py
index 946421ce..f92283bc 100644
--- a/waflib/Logs.py
+++ b/waflib/Logs.py
@@ -344,5 +344,5 @@ def pprint(col, msg, label='', sep='\n'):
 	:param sep: a string to append at the end (line separator)
 	:type sep: string
 	"""
-	info("%s%s%s %s" % (colors(col), msg, colors.NORMAL, label), extra={'terminator':sep})
+	info('%s%s%s %s', colors(col), msg, colors.NORMAL, label, extra={'terminator':sep})
 
diff --git a/waflib/Scripting.py b/waflib/Scripting.py
index f6bd6426..75d9af4a 100644
--- a/waflib/Scripting.py
+++ b/waflib/Scripting.py
@@ -28,7 +28,7 @@ def waf_entry_point(current_directory, version, wafdir):
 	Logs.init_log()
 
 	if Context.WAFVERSION != version:
-		Logs.error('Waf script %r and library %r do not match (directory %r)' % (version, Context.WAFVERSION, wafdir))
+		Logs.error('Waf script %r and library %r do not match (directory %r)', version, Context.WAFVERSION, wafdir)
 		sys.exit(1)
 
 	if '--version' in sys.argv:
@@ -80,7 +80,7 @@ def waf_entry_point(current_directory, version, wafdir):
 			lst = os.listdir(cur)
 		except OSError:
 			lst = []
-			Logs.error('Directory %r is unreadable!' % cur)
+			Logs.error('Directory %r is unreadable!', cur)
 		if Options.lockfile in lst:
 			env = ConfigSet.ConfigSet()
 			try:
@@ -106,7 +106,7 @@ def waf_entry_point(current_directory, version, wafdir):
 								load = True
 								break
 				else:
-					Logs.warn('invalid lock file in %s' % cur)
+					Logs.warn('invalid lock file in %s', cur)
 					load = False
 
 				if load:
@@ -135,13 +135,13 @@ def waf_entry_point(current_directory, version, wafdir):
 			ctx.curdir = current_directory
 			ctx.parse_args()
 			sys.exit(0)
-		Logs.error('Waf: Run from a directory containing a file named %r' % Context.WSCRIPT_FILE)
+		Logs.error('Waf: Run from a directory containing a file named %r', Context.WSCRIPT_FILE)
 		sys.exit(1)
 
 	try:
 		os.chdir(Context.run_dir)
 	except OSError:
-		Logs.error('Waf: The folder %r is unreadable' % Context.run_dir)
+		Logs.error('Waf: The folder %r is unreadable', Context.run_dir)
 		sys.exit(1)
 
 	try:
@@ -151,7 +151,7 @@ def waf_entry_point(current_directory, version, wafdir):
 		Logs.error(str(e))
 		sys.exit(1)
 	except Exception as e:
-		Logs.error('Waf: The wscript in %r is unreadable' % Context.run_dir, e)
+		Logs.error('Waf: The wscript in %r is unreadable', Context.run_dir)
 		traceback.print_exc(file=sys.stdout)
 		sys.exit(2)
 
@@ -264,7 +264,7 @@ def run_commands():
 	while Options.commands:
 		cmd_name = Options.commands.pop(0)
 		ctx = run_command(cmd_name)
-		Logs.info('%r finished successfully (%s)' % (cmd_name, str(ctx.log_timer)))
+		Logs.info('%r finished successfully (%s)', cmd_name, ctx.log_timer)
 	run_command('shutdown')
 
 ###########################################################################################
@@ -285,7 +285,7 @@ def distclean_dir(dirname):
 				try:
 					os.remove(fname)
 				except OSError:
-					Logs.warn('Could not remove %r' % fname)
+					Logs.warn('Could not remove %r', fname)
 
 	for x in (Context.DBFILE, 'config.log'):
 		try:
@@ -306,7 +306,7 @@ def distclean(ctx):
 			try:
 				proj = ConfigSet.ConfigSet(f)
 			except IOError:
-				Logs.warn('Could not read %r' % f)
+				Logs.warn('Could not read %r', f)
 				continue
 
 			if proj['out_dir'] != proj['top_dir']:
@@ -316,7 +316,7 @@ def distclean(ctx):
 					pass
 				except OSError as e:
 					if e.errno != errno.ENOENT:
-						Logs.warn('Could not remove %r' % proj['out_dir'])
+						Logs.warn('Could not remove %r', proj['out_dir'])
 			else:
 				distclean_dir(proj['out_dir'])
 
@@ -326,7 +326,7 @@ def distclean(ctx):
 					os.remove(p)
 				except OSError as e:
 					if e.errno != errno.ENOENT:
-						Logs.warn('Could not remove %r' % p)
+						Logs.warn('Could not remove %r', p)
 
 		# remove local waf cache folders
 		if not Options.commands:
@@ -393,7 +393,7 @@ class Dist(Context.Context):
 		else:
 			digest = ' (sha=%r)' % sha1(node.read()).hexdigest()
 
-		Logs.info('New archive created: %s%s' % (self.arch_name, digest))
+		Logs.info('New archive created: %s%s', self.arch_name, digest)
 
 	def get_tar_path(self, node):
 		"""
diff --git a/waflib/Task.py b/waflib/Task.py
index 18744e82..c9bf6882 100644
--- a/waflib/Task.py
+++ b/waflib/Task.py
@@ -723,7 +723,7 @@ class Task(TaskBase):
 		except (OSError, IOError):
 			for k in bld.node_deps.get(self.uid(), []):
 				if not k.exists():
-					Logs.warn('Dependency %r for %r is missing: check the task declaration and the build order!' % (k, self))
+					Logs.warn('Dependency %r for %r is missing: check the task declaration and the build order!', k, self)
 			raise
 
 	def compute_sig_implicit_deps(self):
diff --git a/waflib/TaskGen.py b/waflib/TaskGen.py
index bfda1c28..c38dda98 100644
--- a/waflib/TaskGen.py
+++ b/waflib/TaskGen.py
@@ -167,7 +167,7 @@ class task_gen(object):
 			st = feats[x]
 			if not st:
 				if not x in Task.classes:
-					Logs.warn('feature %r does not exist - bind at least one method to it' % x)
+					Logs.warn('feature %r does not exist - bind at least one method to it', x)
 			keys.update(list(st)) # ironpython 2.7 wants the cast to list
 
 		# copy the precedence table
diff --git a/waflib/Tools/c_config.py b/waflib/Tools/c_config.py
index 82f1abc6..0c00ebf6 100644
--- a/waflib/Tools/c_config.py
+++ b/waflib/Tools/c_config.py
@@ -274,8 +274,8 @@ def validate_cfg(self, kw):
 		if y in kw:
 			package = kw['package']
 			if Logs.verbose:
-				Logs.warn('Passing %r to conf.check_cfg() is obsolete, pass parameters directly, eg:' % y)
-				Logs.warn(" conf.check_cfg(package='%s', args=['--libs', '--cflags', '%s >= 1.6'])" % (package, package))
+				Logs.warn('Passing %r to conf.check_cfg() is obsolete, pass parameters directly, eg:', y)
+				Logs.warn(" conf.check_cfg(package='%s', args=['--libs', '--cflags', '%s >= 1.6'])", package, package)
 			if not 'msg' in kw:
 				kw['msg'] = 'Checking for %r %s %s' % (package, cfg_ver[x], kw[y])
 			break
diff --git a/waflib/Tools/errcheck.py b/waflib/Tools/errcheck.py
index b66f4fc2..edfa00ed 100644
--- a/waflib/Tools/errcheck.py
+++ b/waflib/Tools/errcheck.py
@@ -58,16 +58,16 @@ def check_same_targets(self):
 			Logs.error(msg)
 			for x in v:
 				if Logs.verbose > 1:
-					Logs.error('  %d. %r' % (1 + v.index(x), x.generator))
+					Logs.error('  %d. %r', 1 + v.index(x), x.generator)
 				else:
-					Logs.error('  %d. %r in %r' % (1 + v.index(x), x.generator.name, getattr(x.generator, 'path', None)))
+					Logs.error('  %d. %r in %r', 1 + v.index(x), x.generator.name, getattr(x.generator, 'path', None))
 
 	if not dupe:
 		for (k, v) in uids.items():
 			if len(v) > 1:
 				Logs.error('* Several tasks use the same identifier. Please check the information on\n   https://waf.io/apidocs/Task.html?highlight=uid#waflib.Task.Task.uid')
 				for tsk in v:
-					Logs.error('  - object %r (%r) defined in %r' % (tsk.__class__.__name__, tsk, tsk.generator))
+					Logs.error('  - object %r (%r) defined in %r', tsk.__class__.__name__, tsk, tsk.generator)
 
 def check_invalid_constraints(self):
 	feat = set([])
@@ -81,7 +81,7 @@ def check_invalid_constraints(self):
 		ext.add(x.__name__)
 	invalid = ext & feat
 	if invalid:
-		Logs.error('The methods %r have invalid annotations:  @extension <-> @feature/@before_method/@after_method' % list(invalid))
+		Logs.error('The methods %r have invalid annotations:  @extension <-> @feature/@before_method/@after_method', list(invalid))
 
 	# the build scripts have been read, so we can check for invalid after/before attributes on task classes
 	for cls in list(Task.classes.values()):
@@ -91,9 +91,9 @@ def check_invalid_constraints(self):
 		for x in ('before', 'after'):
 			for y in Utils.to_list(getattr(cls, x, [])):
 				if not Task.classes.get(y):
-					Logs.error('Erroneous order constraint %r=%r on task class %r' % (x, y, cls.__name__))
+					Logs.error('Erroneous order constraint %r=%r on task class %r', x, y, cls.__name__)
 		if getattr(cls, 'rule', None):
-			Logs.error('Erroneous attribute "rule" on task class %r (rename to "run_str")' % cls.__name__)
+			Logs.error('Erroneous attribute "rule" on task class %r (rename to "run_str")', cls.__name__)
 
 def replace(m):
 	"""
@@ -107,7 +107,7 @@ def replace(m):
 			if x in kw:
 				if x == 'iscopy' and 'subst' in getattr(self, 'features', ''):
 					continue
-				Logs.error('Fix the typo %r -> %r on %r' % (x, typos[x], ret))
+				Logs.error('Fix the typo %r -> %r on %r', x, typos[x], ret)
 		return ret
 	setattr(Build.BuildContext, m, call)
 
@@ -124,11 +124,11 @@ def enhance_lib():
 			lst=Utils.to_list(k[0])
 			for pat in lst:
 				if '..' in pat.split('/'):
-					Logs.error("In ant_glob pattern %r: '..' means 'two dots', not 'parent directory'" % k[0])
+					Logs.error("In ant_glob pattern %r: '..' means 'two dots', not 'parent directory'", k[0])
 		if kw.get('remove', True):
 			try:
 				if self.is_child_of(self.ctx.bldnode) and not kw.get('quiet', False):
-					Logs.error('Using ant_glob on the build folder (%r) is dangerous (quiet=True to disable this warning)' % self)
+					Logs.error('Using ant_glob on the build folder (%r) is dangerous (quiet=True to disable this warning)', self)
 			except AttributeError:
 				pass
 		return self.old_ant_glob(*k, **kw)
@@ -140,7 +140,7 @@ def enhance_lib():
 	def is_before(t1, t2):
 		ret = old(t1, t2)
 		if ret and old(t2, t1):
-			Logs.error('Contradictory order constraints in classes %r %r' % (t1, t2))
+			Logs.error('Contradictory order constraints in classes %r %r', t1, t2)
 		return ret
 	Task.is_before = is_before
 
@@ -152,7 +152,7 @@ def enhance_lib():
 			Logs.error('feature shlib -> cshlib, dshlib or cxxshlib')
 		for x in ('c', 'cxx', 'd', 'fc'):
 			if not x in lst and lst and lst[0] in [x+y for y in ('program', 'shlib', 'stlib')]:
-				Logs.error('%r features is probably missing %r' % (self, x))
+				Logs.error('%r features is probably missing %r', self, x)
 	TaskGen.feature('*')(check_err_features)
 
 	# check for erroneous order constraints
@@ -160,12 +160,12 @@ def enhance_lib():
 		if not hasattr(self, 'rule') and not 'subst' in Utils.to_list(self.features):
 			for x in ('before', 'after', 'ext_in', 'ext_out'):
 				if hasattr(self, x):
-					Logs.warn('Erroneous order constraint %r on non-rule based task generator %r' % (x, self))
+					Logs.warn('Erroneous order constraint %r on non-rule based task generator %r', x, self)
 		else:
 			for x in ('before', 'after'):
 				for y in self.to_list(getattr(self, x, [])):
 					if not Task.classes.get(y, None):
-						Logs.error('Erroneous order constraint %s=%r on %r (no such class)' % (x, y, self))
+						Logs.error('Erroneous order constraint %s=%r on %r (no such class)', x, y, self)
 	TaskGen.feature('*')(check_err_order)
 
 	# check for @extension used with @feature/@before_method/@after_method
diff --git a/waflib/Tools/tex.py b/waflib/Tools/tex.py
index 306f99b7..4dcc3379 100644
--- a/waflib/Tools/tex.py
+++ b/waflib/Tools/tex.py
@@ -239,7 +239,7 @@ class tex(Task.Task):
 			try:
 				ct = aux_node.read()
 			except EnvironmentError:
-				Logs.error('Error reading %s: %r' % aux_node.abspath())
+				Logs.error('Error reading %s: %r', aux_node.abspath())
 				continue
 
 			if g_bibtex_re.findall(ct):
@@ -312,7 +312,7 @@ class tex(Task.Task):
 			try:
 				ct = aux_node.read()
 			except EnvironmentError:
-				Logs.error('Error reading %s: %r' % aux_node.abspath())
+				Logs.error('Error reading %s: %r', aux_node.abspath())
 				continue
 
 			if g_glossaries_re.findall(ct):
@@ -477,9 +477,9 @@ def apply_tex(self):
 						if p:
 							task.texinputs_nodes.append(p)
 						else:
-							Logs.error('Invalid TEXINPUTS folder %s' % x)
+							Logs.error('Invalid TEXINPUTS folder %s', x)
 					else:
-						Logs.error('Cannot resolve relative paths in TEXINPUTS %s' % x)
+						Logs.error('Cannot resolve relative paths in TEXINPUTS %s', x)
 
 		if self.type == 'latex':
 			if 'ps' in outs:
diff --git a/waflib/Tools/vala.py b/waflib/Tools/vala.py
index ddd5ac34..2e90c350 100644
--- a/waflib/Tools/vala.py
+++ b/waflib/Tools/vala.py
@@ -82,7 +82,7 @@ def init_vala_task(self):
 				self.use.append('GTHREAD')
 		else:
 			#Vala doesn't have threading support for dova nor posix
-			Logs.warn("Profile %s means no threading support" % self.profile)
+			Logs.warn('Profile %s means no threading support', self.profile)
 			self.thread = False
 
 		if self.thread:
@@ -172,7 +172,7 @@ def init_vala_task(self):
 		else:
 			v_node = self.path.find_dir(vapi_dir)
 		if not v_node:
-			Logs.warn('Unable to locate Vala API directory: %r' % vapi_dir)
+			Logs.warn('Unable to locate Vala API directory: %r', vapi_dir)
 		else:
 			addflags('--vapidir=%s' % v_node.abspath())
 
diff --git a/waflib/Tools/winres.py b/waflib/Tools/winres.py
index 6c7e66ae..50a4f408 100644
--- a/waflib/Tools/winres.py
+++ b/waflib/Tools/winres.py
@@ -70,7 +70,7 @@ class rc_parser(c_preproc.c_parser):
 			raise c_preproc.PreprocError("could not read the file %s" % filepath)
 		except Exception:
 			if Logs.verbose > 0:
-				Logs.error("parsing %s failed" % filepath)
+				Logs.error("parsing %s failed", filepath)
 				traceback.print_exc()
 
 class winrc(Task.Task):
diff --git a/waflib/extras/boost.py b/waflib/extras/boost.py
index c9367a38..107c1d93 100644
--- a/waflib/extras/boost.py
+++ b/waflib/extras/boost.py
@@ -161,7 +161,7 @@ def boost_get_version(self, d):
 		try:
 			txt = node.read()
 		except EnvironmentError:
-			Logs.error("Could not read the file %r" % node.abspath())
+			Logs.error("Could not read the file %r", node.abspath())
 		else:
 			re_but1 = re.compile('^#define\\s+BOOST_LIB_VERSION\\s+"(.+)"', re.M)
 			m1 = re_but1.search(txt)
diff --git a/waflib/extras/build_logs.py b/waflib/extras/build_logs.py
index 7ccb18a7..9feb2239 100644
--- a/waflib/extras/build_logs.py
+++ b/waflib/extras/build_logs.py
@@ -96,7 +96,7 @@ def exit_cleanup():
 		fileobj.close()
 		filename = sys.stdout.filename
 
-		Logs.info('Output logged to %r' % filename)
+		Logs.info('Output logged to %r', filename)
 
 		# then copy the log file to "latest.log" if possible
 		up = os.path.dirname(os.path.abspath(filename))
diff --git a/waflib/extras/clang_compilation_database.py b/waflib/extras/clang_compilation_database.py
index a9e61ff0..5229360e 100644
--- a/waflib/extras/clang_compilation_database.py
+++ b/waflib/extras/clang_compilation_database.py
@@ -40,7 +40,7 @@ def collect_compilation_db_tasks(self):
 def write_compilation_database(ctx):
 	"Write the clang compilation database as JSON"
 	database_file = ctx.bldnode.make_node('compile_commands.json')
-	Logs.info("Build commands will be stored in %s" % database_file.path_from(ctx.path))
+	Logs.info('Build commands will be stored in %s', database_file.path_from(ctx.path))
 	try:
 		root = json.load(database_file)
 	except IOError:
diff --git a/waflib/extras/codelite.py b/waflib/extras/codelite.py
index 866a01b3..794875a0 100644
--- a/waflib/extras/codelite.py
+++ b/waflib/extras/codelite.py
@@ -325,7 +325,7 @@ def stealth_write(self, data, flags='wb'):
         except (IOError, ValueError):
                 self.write(data, flags=flags)
         else:
-                Logs.debug('codelite: skipping %s' % self.abspath())
+                Logs.debug('codelite: skipping %r', self)
 Node.Node.stealth_write = stealth_write
 
 re_quote = re.compile("[^a-zA-Z0-9-]")
@@ -470,7 +470,7 @@ class vsnode_project(vsnode):
                 return lst
 
         def write(self):
-                Logs.debug('codelite: creating %r' % self.path)
+                Logs.debug('codelite: creating %r', self.path)
                 #print "self.name:",self.name
 
                 # first write the project file
@@ -737,22 +737,20 @@ class codelite_generator(BuildContext):
                                 return ''
                         return getattr(x, 'path', None) and x.path.abspath() or x.name
                 self.all_projects.sort(key=sortfun)
-                
 
         def write_files(self):
-                
                 """
                 Write the project and solution files from the data collected
                 so far. It is unlikely that you will want to change this
                 """
-                for p in self.all_projects:                        
+                for p in self.all_projects:
                         p.write()
 
                 # and finally write the solution file
                 node = self.get_solution_node()
                 node.parent.mkdir()
-                Logs.warn('Creating %r' % node)
-                #a = dir(self.root)                
+                Logs.warn('Creating %r', node)
+                #a = dir(self.root)
                 #for b in a:
                 #        print b
                 #print self.group_names
diff --git a/waflib/extras/compat15.py b/waflib/extras/compat15.py
index ed08c394..afce50d5 100644
--- a/waflib/extras/compat15.py
+++ b/waflib/extras/compat15.py
@@ -107,7 +107,7 @@ def retrieve(self, name, fromenv=None):
 		self.all_envs[name] = env
 	else:
 		if fromenv:
-			Logs.warn("The environment %s may have been configured already" % name)
+			Logs.warn('The environment %s may have been configured already', name)
 	return env
 Configure.ConfigurationContext.retrieve = retrieve
 
@@ -171,15 +171,15 @@ def load_module(path, encoding=None):
 	ret = rev(path, encoding)
 	if 'set_options' in ret.__dict__:
 		if Logs.verbose:
-			Logs.warn('compat: rename "set_options" to "options" (%r)' % path)
+			Logs.warn('compat: rename "set_options" to "options" (%r)', path)
 		ret.options = ret.set_options
 	if 'srcdir' in ret.__dict__:
 		if Logs.verbose:
-			Logs.warn('compat: rename "srcdir" to "top" (%r)' % path)
+			Logs.warn('compat: rename "srcdir" to "top" (%r)', path)
 		ret.top = ret.srcdir
 	if 'blddir' in ret.__dict__:
 		if Logs.verbose:
-			Logs.warn('compat: rename "blddir" to "out" (%r)' % path)
+			Logs.warn('compat: rename "blddir" to "out" (%r)', path)
 		ret.out = ret.blddir
 	Utils.g_module = Context.g_module
 	Options.launch_dir = Context.launch_dir
@@ -375,10 +375,10 @@ def install_dir(self, path):
 	destpath = Utils.subst_vars(path, self.env)
 
 	if self.is_install > 0:
-		Logs.info('* creating %s' % destpath)
+		Logs.info('* creating %s', destpath)
 		Utils.check_dir(destpath)
 	elif self.is_install < 0:
-		Logs.info('* removing %s' % destpath)
+		Logs.info('* removing %s', destpath)
 		try:
 			os.remove(destpath)
 		except OSError:
diff --git a/waflib/extras/cython.py b/waflib/extras/cython.py
index 8e2b2f47..2b2c7ccc 100644
--- a/waflib/extras/cython.py
+++ b/waflib/extras/cython.py
@@ -2,7 +2,7 @@
 # encoding: utf-8
 # Thomas Nagy, 2010-2015
 
-import os, re
+import re
 from waflib import Task, Logs
 from waflib.TaskGen import extension
 
@@ -70,7 +70,7 @@ class cython(Task.Task):
 			if x.name.endswith('.h'):
 				if not x.exists():
 					if Logs.verbose:
-						Logs.warn('Expected %r' % x.abspath())
+						Logs.warn('Expected %r', x.abspath())
 					x.write('')
 		return Task.Task.post_run(self)
 
@@ -92,7 +92,7 @@ class cython(Task.Task):
 			else:
 				mods.append(m.group(2))
 
-		Logs.debug("cython: mods %r" % mods)
+		Logs.debug('cython: mods %r', mods)
 		incs = getattr(self.generator, 'cython_includes', [])
 		incs = [self.generator.path.find_dir(x) for x in incs]
 		incs.append(node.parent)
@@ -113,7 +113,7 @@ class cython(Task.Task):
 		if implicit:
 			found.append(implicit)
 
-		Logs.debug("cython: found %r" % found)
+		Logs.debug('cython: found %r', found)
 
 		# Now the .h created - store them in bld.raw_deps for later use
 		has_api = False
diff --git a/waflib/extras/distnet.py b/waflib/extras/distnet.py
index 1c5f3e60..54572e60 100644
--- a/waflib/extras/distnet.py
+++ b/waflib/extras/distnet.py
@@ -107,10 +107,10 @@ class package(Context.Context):
 					tarinfo.name = os.path.split(x)[1]
 				else:
 					tarinfo.name = endname + x # todo, if tuple, then..
-				Logs.debug("adding %r to %s" % (tarinfo.name, filename))
+				Logs.debug('distnet: adding %r to %s', tarinfo.name, filename)
 				with open(x, 'rb') as f:
 					tar.addfile(tarinfo, f)
-		Logs.info('Created %s' % filename)
+		Logs.info('Created %s', filename)
 
 class publish(Context.Context):
 	fun = 'publish'
@@ -223,7 +223,7 @@ class package_reader(Context.Context):
 			try:
 				response = urlopen(req, timeout=TIMEOUT)
 			except URLError as e:
-				Logs.warn('The package server is down! %r' % e)
+				Logs.warn('The package server is down! %r', e)
 				self.constraints = self.local_resolve(text)
 			else:
 				ret = response.read()
@@ -243,11 +243,11 @@ class package_reader(Context.Context):
 
 				reasons = c.why()
 				if len(reasons) == 1:
-					Logs.error('%s but no matching package could be found in this repository' % reasons[0])
+					Logs.error('%s but no matching package could be found in this repository', reasons[0])
 				else:
-					Logs.error('Conflicts on package %r:' % c.pkgname)
+					Logs.error('Conflicts on package %r:', c.pkgname)
 					for r in reasons:
-						Logs.error('  %s' % r)
+						Logs.error('  %s', r)
 		if errors:
 			self.fatal('The package requirements cannot be satisfied!')
 
@@ -255,7 +255,6 @@ class package_reader(Context.Context):
 		try:
 			return self.cache_constraints[(pkgname, pkgver)]
 		except KeyError:
-			#Logs.error("no key %r" % (pkgname, pkgver))
 			text = Utils.readf(os.path.join(get_distnet_cache(), pkgname, pkgver, requires))
 			ret = parse_constraints(text)
 			self.cache_constraints[(pkgname, pkgver)] = ret
diff --git a/waflib/extras/gccdeps.py b/waflib/extras/gccdeps.py
index 9d0eb9d3..72e340ed 100644
--- a/waflib/extras/gccdeps.py
+++ b/waflib/extras/gccdeps.py
@@ -144,14 +144,14 @@ def post_run(self):
 			continue
 		nodes.append(node)
 
-	Logs.debug('deps: gccdeps for %s returned %s' % (str(self), str(nodes)))
+	Logs.debug('deps: gccdeps for %s returned %s', self, nodes)
 
 	bld.node_deps[self.uid()] = nodes
 	bld.raw_deps[self.uid()] = []
 
 	try:
 		del self.cache_sig
-	except:
+	except AttributeError:
 		pass
 
 	Task.Task.post_run(self)
diff --git a/waflib/extras/msvcdeps.py b/waflib/extras/msvcdeps.py
index 98b06776..1ba289bf 100644
--- a/waflib/extras/msvcdeps.py
+++ b/waflib/extras/msvcdeps.py
@@ -130,7 +130,7 @@ def wrap_compiled_task(classname):
                 if not c_preproc.go_absolute:
                     if not (node.is_child_of(bld.srcnode) or node.is_child_of(bld.bldnode)):
                         # System library
-                        Logs.debug('msvcdeps: Ignoring system include %r' % node)
+                        Logs.debug('msvcdeps: Ignoring system include %r', node)
                         continue
 
                 if id(node) == id(self.inputs[0]):
@@ -144,7 +144,7 @@ def wrap_compiled_task(classname):
 
         try:
             del self.cache_sig
-        except:
+        except AttributeError:
             pass
 
         Task.Task.post_run(self)
@@ -222,7 +222,7 @@ def wrap_compiled_task(classname):
                 for line in raw_out.splitlines():
                     if line.startswith(INCLUDE_PATTERN):
                         inc_path = line[len(INCLUDE_PATTERN):].strip()
-                        Logs.debug('msvcdeps: Regex matched %s' % inc_path)
+                        Logs.debug('msvcdeps: Regex matched %s', inc_path)
                         self.msvcdeps_paths.append(inc_path)
                     else:
                         out.append(line)
diff --git a/waflib/extras/msvs.py b/waflib/extras/msvs.py
index 4f97cdee..d50f5c7b 100644
--- a/waflib/extras/msvs.py
+++ b/waflib/extras/msvs.py
@@ -374,7 +374,7 @@ def stealth_write(self, data, flags='wb'):
 	except (IOError, ValueError):
 		self.write(data, flags=flags)
 	else:
-		Logs.debug('msvs: skipping %s' % self.win32path())
+		Logs.debug('msvs: skipping %s', self.win32path())
 Node.Node.stealth_write = stealth_write
 
 re_win32 = re.compile(r'^([/\\]cygdrive)?[/\\]([a-z])([^a-z0-9_-].*)', re.I)
@@ -529,7 +529,7 @@ class vsnode_project(vsnode):
 		return lst
 
 	def write(self):
-		Logs.debug('msvs: creating %r' % self.path)
+		Logs.debug('msvs: creating %r', self.path)
 
 		# first write the project file
 		template1 = compile_template(PROJECT_TEMPLATE)
@@ -794,7 +794,7 @@ class msvs_generator(BuildContext):
 		# and finally write the solution file
 		node = self.get_solution_node()
 		node.parent.mkdir()
-		Logs.warn('Creating %r' % node)
+		Logs.warn('Creating %r', node)
 		template1 = compile_template(SOLUTION_TEMPLATE)
 		sln_str = template1(self)
 		sln_str = rm_blank_lines(sln_str)
@@ -973,7 +973,7 @@ def wrap_2008(cls):
 			return ''
 
 		def write(self):
-			Logs.debug('msvs: creating %r' % self.path)
+			Logs.debug('msvs: creating %r', self.path)
 			template1 = compile_template(self.project_template)
 			proj_str = template1(self)
 			proj_str = rm_blank_lines(proj_str)
diff --git a/waflib/extras/netcache_client.py b/waflib/extras/netcache_client.py
index 068a4f51..b11c1bbb 100644
--- a/waflib/extras/netcache_client.py
+++ b/waflib/extras/netcache_client.py
@@ -146,7 +146,7 @@ def check_cache(conn, ssig):
 			ret = ''.join(buf)
 
 		all_sigs_in_cache = (time.time(), ret.splitlines())
-		Logs.debug('netcache: server cache has %r entries' % len(all_sigs_in_cache[1]))
+		Logs.debug('netcache: server cache has %r entries', len(all_sigs_in_cache[1]))
 
 	if not ssig in all_sigs_in_cache[1]:
 		raise ValueError('no file %s in cache' % ssig)
@@ -215,11 +215,11 @@ def can_retrieve_cache(self):
 				recv_file(conn, ssig, cnt, p)
 				cnt += 1
 		except MissingFile as e:
-			Logs.debug('netcache: file is not in the cache %r' % e)
+			Logs.debug('netcache: file is not in the cache %r', e)
 			err = True
 
 		except Exception as e:
-			Logs.debug('netcache: could not get the files %r' % e)
+			Logs.debug('netcache: could not get the files %r', e)
 			err = True
 
 			# broken connection? remove this one
@@ -259,7 +259,7 @@ def put_files_cache(self):
 					conn = get_connection(push=True)
 				sock_send(conn, ssig, cnt, node.abspath())
 			except Exception as e:
-				Logs.debug("netcache: could not push the files %r" % e)
+				Logs.debug('netcache: could not push the files %r', e)
 
 				# broken connection? remove this one
 				close_connection(conn)
diff --git a/waflib/extras/package.py b/waflib/extras/package.py
index 955daa3b..c06498eb 100644
--- a/waflib/extras/package.py
+++ b/waflib/extras/package.py
@@ -64,7 +64,7 @@ def download_archive(self, src, dst):
 		else:
 			tmp = self.root.make_node(dst)
 			tmp.write(web.read())
-			Logs.warn('Downloaded %s from %s' % (tmp.abspath(), url))
+			Logs.warn('Downloaded %s from %s', tmp.abspath(), url)
 			break
 	else:
 		self.fatal('Could not get the package %s' % src)
diff --git a/waflib/extras/parallel_debug.py b/waflib/extras/parallel_debug.py
index 7d80c56c..8f02b5c3 100644
--- a/waflib/extras/parallel_debug.py
+++ b/waflib/extras/parallel_debug.py
@@ -422,7 +422,7 @@ def make_picture(producer):
 
 	node = producer.bld.path.make_node('pdebug.svg')
 	node.write(txt)
-	Logs.warn('Created the diagram %r' % node.abspath())
+	Logs.warn('Created the diagram %r', node)
 
 def options(opt):
 	opt.add_option('--dtitle', action='store', default='Parallel build representation for %r' % ' '.join(sys.argv),
diff --git a/waflib/extras/print_commands.py b/waflib/extras/print_commands.py
index a9975557..805dac9c 100644
--- a/waflib/extras/print_commands.py
+++ b/waflib/extras/print_commands.py
@@ -20,8 +20,8 @@ def exec_command(self, cmd, **kw):
 	else:
 		txt = ' '.join(repr(x) if ' ' in x else x for x in cmd)
 
-	Logs.debug('runner: %s' % txt)
-	Logs.debug('runner_env: kw=%s' % kw)
+	Logs.debug('runner: %s', txt)
+	Logs.debug('runner_env: kw=%s', kw)
 
 	if self.logger:
 		self.logger.info(cmd)
diff --git a/waflib/extras/rst.py b/waflib/extras/rst.py
index cf8b2b49..f3c3a5eb 100644
--- a/waflib/extras/rst.py
+++ b/waflib/extras/rst.py
@@ -49,13 +49,13 @@ def parse_rst_node(task, node, nodes, names, seen, dirs=None):
 	for match in re_rst.finditer(code):
 		ipath = match.group('file')
 		itype = match.group('type')
-		Logs.debug("rst: visiting %s: %s" % (itype, ipath))
+		Logs.debug('rst: visiting %s: %s', itype, ipath)
 		found = False
 		for d in dirs:
-			Logs.debug("rst: looking for %s in %s" % (ipath, d.abspath()))
+			Logs.debug('rst: looking for %s in %s', ipath, d.abspath())
 			found = d.find_node(ipath)
 			if found:
-				Logs.debug("rst: found %s as %s" % (ipath, found.abspath()))
+				Logs.debug('rst: found %s as %s', ipath, found.abspath())
 				nodes.append((itype, found))
 				if itype == 'include':
 					parse_rst_node(task, found, nodes, names, seen)
@@ -84,9 +84,9 @@ class docutils(Task.Task):
 
 		parse_rst_node(self, node, nodes, names, seen)
 
-		Logs.debug("rst: %s: found the following file deps: %s" % (repr(self), nodes))
+		Logs.debug('rst: %r: found the following file deps: %r', self, nodes)
 		if names:
-			Logs.warn("rst: %s: could not find the following file deps: %s" % (repr(self), names))
+			Logs.warn('rst: %r: could not find the following file deps: %r', self, names)
 
 		return ([v for (t,v) in nodes], [v for (t,v) in names])
 
@@ -100,7 +100,7 @@ class docutils(Task.Task):
 		:type retcode: boolean
 		"""
 		if retcode != 0:
-			raise Errors.WafError("%r command exit status %r" % (msg, retcode))
+			raise Errors.WafError('%r command exit status %r' % (msg, retcode))
 
 	def run(self):
 		"""
@@ -124,7 +124,7 @@ class rst2html(docutils):
 			if stylesheet is not None:
 				ssnode = self.generator.to_nodes(stylesheet)[0]
 				nodes.append(ssnode)
-				Logs.debug("rst: adding dep to %s %s" % (attribute, stylesheet))
+				Logs.debug('rst: adding dep to %s %s', attribute, stylesheet)
 
 		return nodes, names
 
diff --git a/waflib/extras/run_do_script.py b/waflib/extras/run_do_script.py
index 2bf71489..64df04a1 100644
--- a/waflib/extras/run_do_script.py
+++ b/waflib/extras/run_do_script.py
@@ -84,8 +84,8 @@ class run_do_script(run_do_script_base):
 		run_do_script_base.run(self)
 		ret, log_tail  = self.check_erase_log_file()
 		if ret:
-			Logs.error("""Running Stata on %s failed with code %r.\n\nCheck the log file %s, last 10 lines\n\n%s\n\n\n""" % (
-				self.inputs[0].abspath(), ret, self.env.LOGFILEPATH, log_tail))
+			Logs.error("""Running Stata on %r failed with code %r.\n\nCheck the log file %s, last 10 lines\n\n%s\n\n\n""",
+				self.inputs[0], ret, self.env.LOGFILEPATH, log_tail)
 		return ret
 
 	def check_erase_log_file(self):
@@ -133,7 +133,7 @@ def apply_run_do_script(tg):
 		if not node:
 			tg.bld.fatal('Could not find dependency %r for running %r' % (x, src_node.abspath()))
 		tsk.dep_nodes.append(node)
-	Logs.debug('deps: found dependencies %r for running %r' % (tsk.dep_nodes, src_node.abspath()))
+	Logs.debug('deps: found dependencies %r for running %r', tsk.dep_nodes, src_node.abspath())
 
 	# Bypass the execution of process_source by setting the source to an empty list
 	tg.source = []
diff --git a/waflib/extras/run_m_script.py b/waflib/extras/run_m_script.py
index 534c8d92..142a0d77 100644
--- a/waflib/extras/run_m_script.py
+++ b/waflib/extras/run_m_script.py
@@ -55,8 +55,8 @@ class run_m_script(run_m_script_base):
 				mode = 'rb'
 			with open(logfile, mode=mode) as f:
 				tail = f.readlines()[-10:]
-			Logs.error("""Running Matlab on %s returned the error %r\n\nCheck the log file %s, last 10 lines\n\n%s\n\n\n""" % (
-				self.inputs[0].abspath(), ret, logfile, '\n'.join(tail)))
+			Logs.error("""Running Matlab on %r returned the error %r\n\nCheck the log file %s, last 10 lines\n\n%s\n\n\n""",
+				self.inputs[0], ret, logfile, '\n'.join(tail))
 		else:
 			os.remove(logfile)
 		return ret
@@ -83,7 +83,7 @@ def apply_run_m_script(tg):
 		if not node:
 			tg.bld.fatal('Could not find dependency %r for running %r' % (x, src_node.abspath()))
 		tsk.dep_nodes.append(node)
-	Logs.debug('deps: found dependencies %r for running %r' % (tsk.dep_nodes, src_node.abspath()))
+	Logs.debug('deps: found dependencies %r for running %r', tsk.dep_nodes, src_node.abspath())
 
 	# Bypass the execution of process_source by setting the source to an empty list
 	tg.source = []
diff --git a/waflib/extras/run_py_script.py b/waflib/extras/run_py_script.py
index 99370efc..fafd3e9a 100644
--- a/waflib/extras/run_py_script.py
+++ b/waflib/extras/run_py_script.py
@@ -51,25 +51,24 @@ class run_py_3_script(Task.Task):
 @TaskGen.before_method('process_source')
 def apply_run_py_script(tg):
 	"""Task generator for running either Python 2 or Python 3 on a single
-	script. 
-	
+	script.
+
 	Attributes:
 
 		* source -- A **single** source node or string. (required)
 		* target -- A single target or list of targets (nodes or strings). 
 		* deps -- A single dependency or list of dependencies (nodes or strings)
 		* add_to_pythonpath -- A string that will be appended to the PYTHONPATH environment variable.
-	
+
 	If the build environment has an attribute "PROJECT_PATHS" with
 	a key "PROJECT_ROOT", its value will be appended to the PYTHONPATH.
-	
 	"""
 
 	# Set the Python version to use, default to 3.
 	v = getattr(tg, 'version', 3)
 	if v not in (2, 3): raise ValueError("Specify the 'version' attribute for run_py_script task generator as integer 2 or 3.\n Got: %s" %v)
 
-	# Convert sources and targets to nodes 
+	# Convert sources and targets to nodes
 	src_node = tg.path.find_resource(tg.source)
 	tgt_nodes = [tg.path.find_or_declare(t) for t in tg.to_list(tg.target)]
 
@@ -99,7 +98,7 @@ def apply_run_py_script(tg):
 		if not node:
 			tg.bld.fatal('Could not find dependency %r for running %r' % (x, src_node.abspath()))
 		tsk.dep_nodes.append(node)
-	Logs.debug('deps: found dependencies %r for running %r' % (tsk.dep_nodes, src_node.abspath()))
+	Logs.debug('deps: found dependencies %r for running %r', tsk.dep_nodes, src_node.abspath())
 
 	# Bypass the execution of process_source by setting the source to an empty list
 	tg.source = []
diff --git a/waflib/extras/run_r_script.py b/waflib/extras/run_r_script.py
index 8f3e0c86..200e9af6 100644
--- a/waflib/extras/run_r_script.py
+++ b/waflib/extras/run_r_script.py
@@ -6,12 +6,12 @@
 Run a R script in the directory specified by **ctx.bldnode**.
 
 For error-catching purposes, keep an own log-file that is destroyed if the
-task finished without error. If not, it will show up as rscript_[index].log 
+task finished without error. If not, it will show up as rscript_[index].log
 in the bldnode directory.
 
 Usage::
 
-    ctx(features='run_r_script', 
+    ctx(features='run_r_script',
         source='some_script.r',
         target=['some_table.tex', 'some_figure.eps'],
         deps='some_data.csv')
@@ -53,8 +53,8 @@ class run_r_script(run_r_script_base):
 				mode = 'rb'
 			with open(logfile, mode=mode) as f:
 				tail = f.readlines()[-10:]
-			Logs.error("""Running R on %s returned the error %r\n\nCheck the log file %s, last 10 lines\n\n%s\n\n\n""" % (
-				self.inputs[0].abspath(), ret, logfile, '\n'.join(tail)))
+			Logs.error("""Running R on %r returned the error %r\n\nCheck the log file %s, last 10 lines\n\n%s\n\n\n""",
+				self.inputs[0], ret, logfile, '\n'.join(tail))
 		else:
 			os.remove(logfile)
 		return ret
@@ -80,7 +80,7 @@ def apply_run_r_script(tg):
 		if not node:
 			tg.bld.fatal('Could not find dependency %r for running %r' % (x, src_node.abspath()))
 		tsk.dep_nodes.append(node)
-	Logs.debug('deps: found dependencies %r for running %r' % (tsk.dep_nodes, src_node.abspath()))
+	Logs.debug('deps: found dependencies %r for running %r', tsk.dep_nodes, src_node.abspath())
 
 	# Bypass the execution of process_source by setting the source to an empty list
 	tg.source = []
diff --git a/waflib/extras/sas.py b/waflib/extras/sas.py
index 3b680636..d0f463d6 100644
--- a/waflib/extras/sas.py
+++ b/waflib/extras/sas.py
@@ -22,7 +22,7 @@ class sas(Task.Task):
 
 		# set the cwd
 		task.cwd = task.inputs[0].parent.get_src().abspath()
-		Logs.debug('runner: %s on %s' % (command, node.abspath))
+		Logs.debug('runner: %r on %r', command, node)
 
 		SASINPUTS = node.parent.get_bld().abspath() + os.pathsep + node.parent.get_src().abspath() + os.pathsep
 		task.env.env = {'SASINPUTS': SASINPUTS}
@@ -32,10 +32,10 @@ class sas(Task.Task):
 		task.env.LSTFILE = lstfilenode.abspath()
 		ret = fun(task)
 		if ret:
-			Logs.error('Running %s on %r returned a non-zero exit' % (command, node))
-			Logs.error('SRCFILE = %r' % node)
-			Logs.error('LOGFILE = %r' % logfilenode)
-			Logs.error('LSTFILE = %r' % lstfilenode)
+			Logs.error('Running %s on %r returned a non-zero exit', command, node)
+			Logs.error('SRCFILE = %r', node)
+			Logs.error('LOGFILE = %r', logfilenode)
+			Logs.error('LSTFILE = %r', lstfilenode)
 		return ret
 
 @feature('sas')
diff --git a/waflib/extras/stale.py b/waflib/extras/stale.py
index c89550e2..9e48d0a1 100644
--- a/waflib/extras/stale.py
+++ b/waflib/extras/stale.py
@@ -59,7 +59,7 @@ def stale_rec(node, nodes):
 		else:
 			if not node in nodes:
 				if can_delete(node):
-					Logs.warn("Removing stale file -> %s" % node.abspath())
+					Logs.warn('Removing stale file -> %r', node)
 					node.delete()
 
 old = Parallel.refill_task_list
diff --git a/waflib/extras/stracedeps.py b/waflib/extras/stracedeps.py
index f9102865..68d6db3d 100644
--- a/waflib/extras/stracedeps.py
+++ b/waflib/extras/stracedeps.py
@@ -162,7 +162,7 @@ def parse_strace_deps(self, path, cwd):
 
 	# record the dependencies then force the task signature recalculation for next time
 	if Logs.verbose:
-		Logs.debug('deps: real scanner for %s returned %s' % (str(self), str(nodes)))
+		Logs.debug('deps: real scanner for %r returned %r', self, nodes)
 	bld = self.generator.bld
 	bld.node_deps[self.uid()] = nodes
 	bld.raw_deps[self.uid()] = []
diff --git a/waflib/extras/swig.py b/waflib/extras/swig.py
index 0671f2c3..eeb99522 100644
--- a/waflib/extras/swig.py
+++ b/waflib/extras/swig.py
@@ -87,7 +87,7 @@ class swig(Task.Task):
 						to_see.append(u)
 						break
 				else:
-					Logs.warn('could not find %r' % n)
+					Logs.warn('could not find %r', n)
 
 		return (lst_src, [])
 
diff --git a/waflib/extras/use_config.py b/waflib/extras/use_config.py
index 5eaced24..6859bed3 100644
--- a/waflib/extras/use_config.py
+++ b/waflib/extras/use_config.py
@@ -130,12 +130,12 @@ def download_tool(tool, force=False, ctx=None):
 			else:
 				tmp = ctx.root.make_node(os.sep.join((Context.waf_dir, 'waflib', 'extras', tool + '.py')))
 				tmp.write(web.read(), 'wb')
-				Logs.warn('Downloaded %s from %s' % (tool, url))
+				Logs.warn('Downloaded %s from %s', tool, url)
 				download_check(tmp)
 				try:
 					module = Context.load_tool(tool)
 				except Exception:
-					Logs.warn('The tool %s from %s is unusable' % (tool, url))
+					Logs.warn('The tool %s from %s is unusable', tool, url)
 					try:
 						tmp.delete()
 					except Exception:
diff --git a/waflib/extras/valadoc.py b/waflib/extras/valadoc.py
index 335f11ac..c50f69e7 100644
--- a/waflib/extras/valadoc.py
+++ b/waflib/extras/valadoc.py
@@ -113,7 +113,7 @@ def process_valadoc(self):
 			try:
 				task.vapi_dirs.append(self.path.find_dir(vapi_dir).abspath())
 			except AttributeError:
-				Logs.warn("Unable to locate Vala API directory: '%s'" % vapi_dir)
+				Logs.warn('Unable to locate Vala API directory: %r', vapi_dir)
 	if getattr(self, 'files', None):
 		task.files = self.files
 	else:
diff --git a/waflib/extras/why.py b/waflib/extras/why.py
index b2f5d7e1..9f3ab27a 100644
--- a/waflib/extras/why.py
+++ b/waflib/extras/why.py
@@ -62,7 +62,7 @@ def runnable_status(self):
 			def v(x):
 				return Utils.to_hex(x)
 
-			Logs.debug("Task %r" % self)
+			Logs.debug('Task %r', self)
 			msgs = ['* Implicit or scanner dependency', '* Task code', '* Source file, explicit or manual dependency', '* Configuration data variable']
 			tmp = 'task: -> %s: %s %s'
 			for x in range(len(msgs)):
@@ -70,7 +70,7 @@ def runnable_status(self):
 				a = new_sigs[x*l : (x+1)*l]
 				b = old_sigs[x*l : (x+1)*l]
 				if (a != b):
-					Logs.debug(tmp % (msgs[x].ljust(35), v(a), v(b)))
+					Logs.debug(tmp, msgs[x].ljust(35), v(a), v(b))
 	return ret
 Task.Task.runnable_status = runnable_status
 
diff --git a/waflib/extras/win32_opts.py b/waflib/extras/win32_opts.py
index 85fcef22..6d2f360b 100644
--- a/waflib/extras/win32_opts.py
+++ b/waflib/extras/win32_opts.py
@@ -120,7 +120,7 @@ if Utils.is_win32:
 			find     = FindFirstFile(TP % curpath, ctypes.byref(findData))
 
 			if find == INVALID_HANDLE_VALUE:
-				Logs.error("invalid win32 handle isfile_cached %r" % self.abspath())
+				Logs.error("invalid win32 handle isfile_cached %r", self.abspath())
 				return os.path.isfile(self.abspath())
 
 			try:
@@ -132,7 +132,7 @@ if Utils.is_win32:
 					if not FindNextFile(find, ctypes.byref(findData)):
 						break
 			except Exception as e:
-				Logs.error('exception while listing a folder %r %r' % (self.abspath(), e))
+				Logs.error('exception while listing a folder %r %r', self.abspath(), e)
 				return os.path.isfile(self.abspath())
 			finally:
 				FindClose(find)
diff --git a/waflib/extras/xcode6.py b/waflib/extras/xcode6.py
index 2b4480f1..ac161320 100644
--- a/waflib/extras/xcode6.py
+++ b/waflib/extras/xcode6.py
@@ -53,9 +53,8 @@ $ waf configure xcode6
 
 # TODO: support iOS projects
 
-from waflib import Context, TaskGen, Build, Utils, ConfigSet, Configure, Errors
-from waflib.Build import BuildContext
-import os, sys, random, time
+from waflib import Context, TaskGen, Build, Utils, Errors
+import os, sys
 
 HEADERS_GLOB = '**/(*.h|*.hpp|*.H|*.inl)'
 
diff --git a/wscript b/wscript
index 6435909b..3b23560f 100644
--- a/wscript
+++ b/wscript
@@ -267,8 +267,8 @@ def create_waf(self, *k, **kw):
 			files = [x.name for x in tar.getmembers()]
 			if set(files) ^ set(oldfiles):
 				Logs.warn('The archive model has differences:')
-				Logs.warn('- Added %r' % list(set(files) - set(oldfiles)))
-				Logs.warn('- Removed %r' % list(set(oldfiles) - set(files)))
+				Logs.warn('- Added %r', list(set(files) - set(oldfiles)))
+				Logs.warn('- Removed %r', list(set(oldfiles) - set(files)))
 
 	#open a file as tar.[extension] for writing
 	tar = tarfile.open('%s.tar.%s' % (mw, zipType), "w:%s" % zipType)