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

4 files changed, 112 insertions, 13 deletions

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))