Add an option to not save the --debug=explain information.

8 files changed, 133 insertions, 30 deletions

diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index 704d7b7..ee75857 100644
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -94,6 +94,11 @@ RELEASE 0.96 - XXX
   - Add a --debug=explain option that reports the reason(s) why SCons
     thinks it must rebuild something.
 
+  - Add --save-explain-info and SetOption('save_explain_info') options
+    to control whether the --debug=explain information is saved in
+    the .sconsign file(s).  Not saving this information can improve
+    performance and save memory usage.
+
   - Add support for functions that return platform-independent Actions
     to Chmod(), Copy(), Delete(), Mkdir(), Move() and Touch() files
     and/or directories.  Like any other Actions, the returned Action
diff --git a/src/engine/SCons/Node/FS.py b/src/engine/SCons/Node/FS.py
index 23cf8a7..2f115c9 100644
--- a/src/engine/SCons/Node/FS.py
+++ b/src/engine/SCons/Node/FS.py
@@ -1385,7 +1385,34 @@ class File(Base):
             return 0
 
     def store_info(self, obj):
-        self.dir.sconsign().set_entry(self.name, obj)
+        # Merge our build information into the already-stored entry.
+        # This accomodates "chained builds" where a file that's a target
+        # in one build (SConstruct file) is a source in a different build.
+        # See test/chained-build.py for the use case.
+        entry = self.get_stored_info()
+        if not SCons.Node.Save_Explain_Info:
+            # If we're not saving explanation info, wipe out any that
+            # might be in the already-stored entry.
+            #
+            # XXX This is kind of bad that we're naming attributes that
+            # are really controlled in Node/__init__.py.  It would be
+            # good to find a way to move this logic there in some way
+            # that still accounts for the fact that not all Node classes
+            # need or use this information.
+            attributes = [
+                'bsources',     'bsourcesigs',
+                'bdepends',     'bdependsigs',
+                'bimplicit',    'bimplicitsigs',
+                'bact',         'bactsig',
+            ]
+            for attr in attributes:
+                try:
+                     delattr(entry, attr)
+                except AttributeError:
+                    pass
+        for key, val in obj.__dict__.items():
+            entry.__dict__[key] = val
+        sconsign = self.dir.sconsign().set_entry(self.name, entry)
 
     def get_stored_info(self):
         try:
diff --git a/src/engine/SCons/Node/FSTests.py b/src/engine/SCons/Node/FSTests.py
index d9ffd83..d4137c1 100644
--- a/src/engine/SCons/Node/FSTests.py
+++ b/src/engine/SCons/Node/FSTests.py
@@ -1969,6 +1969,55 @@ class SaveStringsTestCase(unittest.TestCase):
         expect = map(os.path.normpath, ['src/f', 'd1/f', 'd0/b', 'd1/b'])
         assert s == expect, s
 
+class SaveExplainInfoTestCase(unittest.TestCase):
+    def runTest(self):
+        """Test how we store --debug=explain info."""
+        test=TestCmd(workdir='')
+        fs = SCons.Node.FS.FS(test.workpath('fs'))
+        f = fs.File('file')
+
+        class BInfo:
+            pass
+
+        bi = BInfo()
+        bi.bact = 'file bact'
+        bi.arg1 = 'file arg1'
+        f.store_info(bi)
+
+        i = f.get_stored_info()
+        assert i.bact == 'file bact', i.arg1
+        assert i.arg1 == 'file arg1', i.arg1
+        assert not hasattr(i, 'arg2'), i.bact
+        assert not hasattr(i, 'arg3'), i.bact
+
+        save_value = SCons.Node.Save_Explain_Info
+        try:
+            SCons.Node.Save_Explain_Info = 1
+
+            bi = BInfo()
+            bi.arg2 = 'file arg2'
+            f.store_info(bi)
+
+            i = f.get_stored_info()
+            assert i.bact == 'file bact', i.arg1
+            assert i.arg1 == 'file arg1', i.arg1
+            assert i.arg2 == 'file arg2', i.arg2
+            assert not hasattr(i, 'arg3'), i.bact
+
+            SCons.Node.Save_Explain_Info = 0
+
+            bi = BInfo()
+            bi.arg3 = 'file arg3'
+            f.store_info(bi)
+
+            i = f.get_stored_info()
+            assert not hasattr(i, 'bact'), i.bact
+            assert i.arg1 == 'file arg1', i.arg1
+            assert i.arg2 == 'file arg2', i.arg2
+            assert i.arg3 == 'file arg3', i.arg2
+        finally:
+            SCons.Node.Save_Explain_Info = save_value
+
 
 
 if __name__ == "__main__":
@@ -1989,5 +2038,6 @@ if __name__ == "__main__":
     suite.addTest(postprocessTestCase())
     suite.addTest(SpecialAttrTestCase())
     suite.addTest(SaveStringsTestCase())
+    suite.addTest(SaveExplainInfoTestCase())
     if not unittest.TextTestRunner().run(suite).wasSuccessful():
         sys.exit(1)
diff --git a/src/engine/SCons/Node/NodeTests.py b/src/engine/SCons/Node/NodeTests.py
index 4c7d9c2..cd7aa18 100644
--- a/src/engine/SCons/Node/NodeTests.py
+++ b/src/engine/SCons/Node/NodeTests.py
@@ -396,6 +396,7 @@ class NodeTestCase(unittest.TestCase):
                     def collect(self, args):
                         return reduce(lambda x, y: x+y, args, self.val)
                 self.module = M(val)
+
         node = SCons.Node.Node()
         binfo = node.gen_binfo(Calculator(666))
         assert isinstance(binfo, SCons.Node.BuildInfo), binfo
@@ -407,6 +408,19 @@ class NodeTestCase(unittest.TestCase):
         assert hasattr(binfo, 'bimplicitsigs')
         assert binfo.bsig == 666, binfo.bsig
 
+        SCons.Node.Save_Explain_Info = 0
+
+        node = SCons.Node.Node()
+        binfo = node.gen_binfo(Calculator(777))
+        assert isinstance(binfo, SCons.Node.BuildInfo), binfo
+        assert not hasattr(binfo, 'bsources')
+        assert not hasattr(binfo, 'bsourcesigs')
+        assert not hasattr(binfo, 'bdepends')
+        assert not hasattr(binfo, 'bdependsigs')
+        assert not hasattr(binfo, 'bimplicit')
+        assert not hasattr(binfo, 'bimplicitsigs')
+        assert binfo.bsig == 777, binfo.bsig
+
     def test_explain(self):
         """Test explaining why a Node must be rebuilt
         """
diff --git a/src/engine/SCons/Node/__init__.py b/src/engine/SCons/Node/__init__.py
index ba4cbca..64226a6 100644
--- a/src/engine/SCons/Node/__init__.py
+++ b/src/engine/SCons/Node/__init__.py
@@ -76,6 +76,9 @@ implicit_deps_unchanged = 0
 # controls whether the cached implicit deps are ignored:
 implicit_deps_changed = 0
 
+# controls whether --debug=explain info is saved in Nodes:
+Save_Explain_Info = 1
+
 # A variable that can be set to an interface-specific function be called
 # to annotate a Node with information about its creation.
 def do_nothing(node): pass
@@ -542,21 +545,26 @@ class Node:
         dependsigs = map(calc_signature, depends)
         implicitsigs = map(calc_signature, implicit)
 
-        binfo.bsources = map(str, sources)
-        binfo.bdepends = map(str, depends)
-        binfo.bimplicit = map(str, implicit)
-
-        binfo.bsourcesigs = sourcesigs
-        binfo.bdependsigs = dependsigs
-        binfo.bimplicitsigs = implicitsigs
-
         sigs = sourcesigs + dependsigs + implicitsigs
 
-        if self.has_builder():
+        has_builder = self.has_builder()
+        if has_builder:
             executor = self.get_executor()
-            binfo.bact = str(executor)
-            binfo.bactsig = calc.module.signature(executor)
-            sigs.append(binfo.bactsig)
+            bactsig = calc.module.signature(executor)
+            sigs.append(bactsig)
+
+        if Save_Explain_Info:
+            binfo.bsources = map(str, sources)
+            binfo.bdepends = map(str, depends)
+            binfo.bimplicit = map(str, implicit)
+
+            binfo.bsourcesigs = sourcesigs
+            binfo.bdependsigs = dependsigs
+            binfo.bimplicitsigs = implicitsigs
+
+            if has_builder:
+                binfo.bact = str(executor)
+                binfo.bactsig = calc.module.signature(executor)
 
         binfo.bsig = calc.module.collect(filter(None, sigs))
 
diff --git a/src/engine/SCons/SConsign.py b/src/engine/SCons/SConsign.py
index c97f1b6..b7b06fe 100644
--- a/src/engine/SCons/SConsign.py
+++ b/src/engine/SCons/SConsign.py
@@ -68,8 +68,7 @@ class Base:
 
     def get_entry(self, filename):
         """
-        Create an entry for the filename and return it, or if one already exists,
-        then return it.
+        Fetch the specified entry attribute.
         """
         return self.entries[filename]
 
@@ -77,13 +76,7 @@ class Base:
         """
         Set the entry.
         """
-        try:
-            entry = self.entries[filename]
-        except KeyError:
-            self.entries[filename] = obj
-        else:
-            for key, val in obj.__dict__.items():
-                entry.__dict__[key] = val
+        self.entries[filename] = obj
         self.dirty = 1
 
 class DB(Base):
diff --git a/src/engine/SCons/SConsignTests.py b/src/engine/SCons/SConsignTests.py
index 79f4387..16ef816 100644
--- a/src/engine/SCons/SConsignTests.py
+++ b/src/engine/SCons/SConsignTests.py
@@ -47,8 +47,9 @@ class BaseTestCase(unittest.TestCase):
 
         aaa = BuildInfo('aaa')
         bbb = BuildInfo('bbb')
+        bbb.arg1 = 'bbb arg1'
         ccc = BuildInfo('ccc')
-        ccc.arg = 'ccc arg'
+        ccc.arg2 = 'ccc arg2'
 
         f = SCons.SConsign.Base()
         f.set_entry('aaa', aaa)
@@ -61,12 +62,14 @@ class BaseTestCase(unittest.TestCase):
         e = f.get_entry('bbb')
         assert e == bbb, e
         assert e.name == 'bbb', e.name
-        assert not hasattr(e, 'arg'), e
+        assert e.arg1 == 'bbb arg1', e.arg1
+        assert not hasattr(e, 'arg2'), e
 
         f.set_entry('bbb', ccc)
         e = f.get_entry('bbb')
         assert e.name == 'ccc', e.name
-        assert e.arg == 'ccc arg', e.arg
+        assert not hasattr(e, 'arg1'), e
+        assert e.arg2 == 'ccc arg2', e.arg1
 
         ddd = BuildInfo('ddd')
         eee = BuildInfo('eee')
diff --git a/src/engine/SCons/Script/__init__.py b/src/engine/SCons/Script/__init__.py
index d4650d2..835409e 100644
--- a/src/engine/SCons/Script/__init__.py
+++ b/src/engine/SCons/Script/__init__.py
@@ -528,7 +528,6 @@ class OptParser(OptionParser):
 
         def opt_debug(option, opt, value, parser, debug_options=debug_options):
             if value in debug_options:
-                #setattr(parser.values, 'debug', value)
                 parser.values.debug = value
             else:
                 raise OptionValueError("Warning:  %s is not a valid debug type" % value)
@@ -541,7 +540,6 @@ class OptParser(OptionParser):
         def opt_duplicate(option, opt, value, parser):
             if not value in SCons.Node.FS.Valid_Duplicates:
                 raise OptionValueError("`%s' is not a valid duplication style." % value)
-            #setattr(parser.values, 'duplicate', value)
             parser.values.duplicate = value
             # Set the duplicate style right away so it can affect linking
             # of SConscript files.
@@ -584,7 +582,6 @@ class OptParser(OptionParser):
 
         def opt_j(option, opt, value, parser):
             value = int(value)
-            #setattr(parser.values, 'num_jobs', value)
             parser.values.num_jobs = value
         self.add_option('-j', '--jobs', action="callback", type="int",
                         callback=opt_j, metavar="N",
@@ -627,6 +624,10 @@ class OptParser(OptionParser):
         self.add_option('-s', '--silent', '--quiet', action="store_true",
                         default=0, help="Don't print commands.")
 
+        self.add_option('--save-explain-info', type="int", action="store",
+                        dest='save_explain_info', metavar='0|1',
+                        help="(Don't) save --debug=explain information")
+
         self.add_option('-u', '--up', '--search-up', action="store_const",
                         dest="climb_up", default=0, const=1,
                         help="Search up directory tree for SConstruct,       "
@@ -734,7 +735,8 @@ class SConscriptSettableOptions:
                          'max_drift':SCons.Sig.default_max_drift,
                          'implicit_cache':0,
                          'clean':0,
-                         'duplicate':'hard-soft-copy'}
+                         'duplicate':'hard-soft-copy',
+                         'save_explain_info':1}
 
     def get(self, name):
         if not self.settable.has_key(name):
@@ -770,7 +772,7 @@ class SConscriptSettableOptions:
             # Set the duplicate stye right away so it can affect linking
             # of SConscript files.
             SCons.Node.FS.set_duplicate(value)
-            
+
         self.settable[name] = value
     
 
@@ -947,6 +949,7 @@ def _main(args, parser):
     # that are SConscript settable:
     SCons.Node.implicit_cache = ssoptions.get('implicit_cache')
     SCons.Node.FS.set_duplicate(ssoptions.get('duplicate'))
+    SCons.Node.Save_Explain_Info = ssoptions.get('save_explain_info') or print_explanations
 
     lookup_top = None
     if targets: