8 files changed, 130 insertions, 33 deletions
diff --git a/doc/man/scons.1 b/doc/man/scons.1
index 7eac0e8..1e9086f 100644
--- a/doc/man/scons.1
+++ b/doc/man/scons.1
@@ -135,37 +135,62 @@ ability to define new scanners for unknown input file types.
 .B scons
 is normally executed in a top-level directory containing a
 .I SConstruct
-file, specifying the target or targets to be built as
-command-line arguments.  The command
+file, optionally specifying
+as command-line arguments
+the target file or files to be built.
+
+By default, the command
+
+.ES
+scons
+.EE
+
+will build all target files in or below the current directory.
+Explicit default targets
+(to be built when no targets are specified on the command line)
+may be defined the SConscript file(s)
+using the
+.B Default()
+function, described below.
+
+Even when
+.B Default()
+targets are specified in the SConscript file(s),
+all target files in or below the current directory
+may be built by explicitly specifying
+the current directory (.)
+as a command-line target:
 
 .ES
 scons .
 .EE
 
-will build all target files in or below the current directory 
-.RI ( . ")."
+Building all target files,
+including any files outside of the current directory,
+may be specified by supplying a command-line target
+of the root directory (on POSIX systems):
 
 .ES
 scons /
 .EE
 
-will build all target files in or below the root directory (i.e.,
-all files).  Specific targets may be supplied:
+or the path name(s) of the volume(s) in which all the targets
+should be built (on Windows systems):
 
 .ES
-scons foo bar
+scons C:\ D:\
 .EE
 
-Targets may be omitted from the command line,
-in which case the targets specified
-in the SConscript file(s) as
-.B Default
-targets will be built:
+To build only specific targets,
+supply them as command-line arguments:
 
 .ES
-scons
+scons foo bar
 .EE
 
+in which case only the specified targets will be built
+(along with any derived files on which they depend).
+
 Specifying "cleanup" targets in SConscript files is not
 necessary.  The 
 .B -c
@@ -2511,18 +2536,30 @@ and add to the list of default targets.
 Multiple targets should be specified as
 separate arguments to the
 .BR Default ()
-method or as a list.
+method, or as a list.
 .BR Default ()
-will also accept the return value of any of the construction environment
+will also accept the Node returned by any
+of a construction environment's
 builder methods.
 Examples:
 
 .ES
 Default('foo', 'bar', 'baz')
 Default(['a', 'b', 'c'])
-Default(env.Program('hello', 'hello.c'))
+hello = env.Program('hello', 'hello.c')
+Default(hello)
 .EE
 
+An argument to
+.BR Default ()
+of
+.B None
+will clear all default targets.
+Later calls to
+.BR Default ()
+will add to the (now empty) default-target list
+like normal.
+
 .TP
 .RI Dir( name ", [" directory ])
 This returns an object that represents a given directory 
diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index 0dea107..237aa60 100644
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -60,6 +60,10 @@ RELEASE 0.11 - XXX
     between builds, with related options --cache-disable, --cache-force,
     and --cache-show.
 
+  - Change the default behavior when no targets are specified to build
+    everything in the current directory and below (like Make).  This
+    can be disabled by specifying Default(None) in an SConscript.
+
   From Steve Leblanc:
 
   - Fix the output of -c -n when directories are involved, so it
diff --git a/src/RELEASE.txt b/src/RELEASE.txt
index ccb301c..f6fef16 100644
--- a/src/RELEASE.txt
+++ b/src/RELEASE.txt
@@ -72,6 +72,12 @@ RELEASE 0.10 - Thu, 16 Jan 2003 04:11:46 -0600
     If you have defined a strfunction() for a Python function Action,
     you will need to add a third "env" argument to your function call.
 
+  - The default behavior when no targets are specified has been changed
+    to be like Make: everything in the current directory and below will
+    be built.  This can be disabled by specifying "Default(None)" in an
+    SConscript, in which case there will be no default targets and
+    SCons will print an appropriate error message.
+
   Please note the following important changes since release 0.09:
 
     - The Scanner interface has been changed to make it easier to
diff --git a/src/engine/SCons/Script/SConscript.py b/src/engine/SCons/Script/SConscript.py
index 7cfb312..5c4a2b3 100644
--- a/src/engine/SCons/Script/SConscript.py
+++ b/src/engine/SCons/Script/SConscript.py
@@ -51,7 +51,7 @@ import sys
 def do_nothing(text): pass
 HelpFunction = do_nothing
 
-default_targets = []
+default_targets = None
 clean_targets = {}
 arguments = {}
 launch_dir = os.path.abspath(os.curdir)
@@ -204,8 +204,13 @@ def SConscript(*ls, **kw):
         return tuple(results)
     
 def Default(*targets):
+    global default_targets
+    if default_targets is None:
+        default_targets = []
     for t in targets:
-        if isinstance(t, SCons.Node.Node):
+        if t is None:
+            default_targets = []
+        elif isinstance(t, SCons.Node.Node):
             default_targets.append(t)
         else:
             default_targets.extend(SCons.Node.arg2nodes(t,
diff --git a/src/engine/SCons/Script/__init__.py b/src/engine/SCons/Script/__init__.py
index 8bc3da4..eed045d 100644
--- a/src/engine/SCons/Script/__init__.py
+++ b/src/engine/SCons/Script/__init__.py
@@ -811,6 +811,8 @@ def _main():
 
     if not targets:
         targets = SCons.Script.SConscript.default_targets
+        if targets is None:
+            targets = [SCons.Node.FS.default_fs.Dir('.')]
 
     if not targets:
         sys.stderr.write("scons: *** No targets specified and no Default() targets found.  Stop.\n")
diff --git a/test/Default.py b/test/Default.py
index 1c7a638..d2c438f 100644
--- a/test/Default.py
+++ b/test/Default.py
@@ -24,6 +24,10 @@
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+"""
+Verify various combinations of arguments to Default() work properly.
+"""
+
 import os
 import sys
 import TestSCons
@@ -32,7 +36,13 @@ python = TestSCons.python
 
 test = TestSCons.TestSCons()
 
-test.subdir('one', 'two', 'three', 'four', 'five')
+for dir in ['one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight']:
+
+    test.subdir(dir)
+
+    test.write(os.path.join(dir, 'foo.in'), dir + "/foo.in\n");
+
+    test.write(os.path.join(dir, 'bar.in'), dir + "/bar.in\n");
 
 test.write('build.py', r"""
 import sys
@@ -42,6 +52,7 @@ file.write(contents)
 file.close()
 """)
 
+#
 test.write(['one', 'SConstruct'], """
 B = Builder(action = r'%s ../build.py $TARGET $SOURCES')
 env = Environment(BUILDERS = { 'B' : B })
@@ -85,13 +96,6 @@ Default(env.B(target = 'bar.out', source = 'bar.in'))
 
 for dir in ['one', 'two', 'three', 'four', 'five']:
 
-    foo_in = os.path.join(dir, 'foo.in')
-    bar_in = os.path.join(dir, 'bar.in')
-
-    test.write(foo_in, dir + "/foo.in\n");
-
-    test.write(bar_in, dir + "/bar.in\n");
-
     test.run(chdir = dir)	# no arguments, use the Default
 
 test.fail_test(test.read(test.workpath('one', 'foo.out')) != "one/foo.in\n")
@@ -112,6 +116,45 @@ test.fail_test(test.read(test.workpath('five', 'bar.out')) != "five/bar.in\n")
 
 
 
+# Test how a None Default() argument works to disable/reset default targets.
+test.write(['six', 'SConstruct'], """\
+B = Builder(action = r'%s ../build.py $TARGET $SOURCES')
+env = Environment(BUILDERS = { 'B' : B })
+foo = env.B(target = 'foo.out', source = 'foo.in')
+bar = env.B(target = 'bar.out', source = 'bar.in')
+Default(None)
+""" % python)
+
+test.run(chdir = 'six', status = 2, stderr =
+"scons: *** No targets specified and no Default() targets found.  Stop.\n")
+
+test.write(['seven', 'SConstruct'], """\
+B = Builder(action = r'%s ../build.py $TARGET $SOURCES')
+env = Environment(BUILDERS = { 'B' : B })
+foo = env.B(target = 'foo.out', source = 'foo.in')
+bar = env.B(target = 'bar.out', source = 'bar.in')
+Default(foo, bar, None)
+""" % python)
+
+test.run(chdir = 'seven', status = 2, stderr =
+"scons: *** No targets specified and no Default() targets found.  Stop.\n")
+
+test.write(['eight', 'SConstruct'], """\
+B = Builder(action = r'%s ../build.py $TARGET $SOURCES')
+env = Environment(BUILDERS = { 'B' : B })
+foo = env.B(target = 'foo.out', source = 'foo.in')
+bar = env.B(target = 'bar.out', source = 'bar.in')
+Default(foo, None, bar)
+""" % python)
+
+test.run(chdir = 'eight')       # no arguments, use the Default
+
+test.fail_test(os.path.exists(test.workpath('eight', 'foo.out')))
+test.fail_test(test.read(test.workpath('eight', 'bar.out')) != "eight/bar.in\n")
+
+
+
+
 test.subdir('sub1')
 
 test.write('SConstruct', """
diff --git a/test/no-arguments.py b/test/no-arguments.py
index acd590a..602ef80 100644
--- a/test/no-arguments.py
+++ b/test/no-arguments.py
@@ -24,6 +24,12 @@
 
 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
 
+"""
+Verify that we use a default target of the current directory when there
+are no command-line arguments (and, implicitly, no Default() in the
+SConstruct).
+"""
+
 import os.path
 
 import TestSCons
@@ -47,13 +53,9 @@ env.Build('aaa.out', 'aaa.in')
 test.write('aaa.in', "aaa.in\n")
 
 #
-test.run(arguments = '.')
+test.run()
 
 test.fail_test(test.read('aaa.out') != "aaa.in\n")
 
 #
-test.run(status = 2, stderr =
-"scons: *** No targets specified and no Default() targets found.  Stop.\n")
-
-#
 test.pass_test()
diff --git a/test/option-u.py b/test/option-u.py
index f90e258..1f7df7a 100644
--- a/test/option-u.py
+++ b/test/option-u.py
@@ -44,11 +44,9 @@ file.close()
 """)
 
 test.write('SConstruct', """
-import SCons.Defaults
 env = Environment()
 env['BUILDERS']['B'] = Builder(action=r'%s build.py $TARGET $SOURCES')
 env.B(target = 'sub1/foo.out', source = 'sub1/foo.in')
-Default('.')
 Export('env')
 SConscript('sub2/SConscript')
 env.Alias('baz', env.B(target = 'sub3/baz.out', source = 'sub3/baz.in'))