Add the highly anticipated --debug=explain option to provide build reasoning.

4 files changed, 79 insertions, 30 deletions

diff --git a/src/engine/SCons/Node/FS.py b/src/engine/SCons/Node/FS.py
index bb13afc..a349f77 100644
--- a/src/engine/SCons/Node/FS.py
+++ b/src/engine/SCons/Node/FS.py
@@ -1225,13 +1225,13 @@ class Dir(Base):
         """A directory does not get scanned."""
         return None
 
-    def set_bsig(self, bsig):
+    def set_binfo(self, bsig, bkids, bkidsigs, bact, bactsig):
         """A directory has no signature."""
-        bsig = None
+        pass
 
     def set_csig(self, csig):
         """A directory has no signature."""
-        csig = None
+        pass
 
     def get_contents(self):
         """Return aggregate contents of all our children."""
@@ -1363,8 +1363,12 @@ class File(Base):
     def store_csig(self):
         self.dir.sconsign().set_csig(self.name, self.get_csig())
 
-    def store_bsig(self):
-        self.dir.sconsign().set_bsig(self.name, self.get_bsig())
+    def store_binfo(self):
+        binfo = self.get_binfo()
+        apply(self.dir.sconsign().set_binfo, (self.name,) + binfo)
+
+    def get_stored_binfo(self):
+        return self.dir.sconsign().get_binfo(self.name)
 
     def store_implicit(self):
         self.dir.sconsign().set_implicit(self.name, self.implicit)
@@ -1613,7 +1617,7 @@ class File(Base):
                         # ...and they'd like a local copy.
                         LocalCopy(self, r, None)
                         self.set_bsig(bsig)
-                        self.store_bsig()
+                        self.store_binfo()
                     return 1
             self._rfile = self
             return None
diff --git a/src/engine/SCons/Node/FSTests.py b/src/engine/SCons/Node/FSTests.py
index b1999e0..6fbcfdc 100644
--- a/src/engine/SCons/Node/FSTests.py
+++ b/src/engine/SCons/Node/FSTests.py
@@ -815,7 +815,7 @@ class FSTestCase(unittest.TestCase):
         e8 = fs.Entry("e8")
         assert e8.get_bsig() is None, e8.get_bsig()
         assert e8.get_csig() is None, e8.get_csig()
-        e8.set_bsig('xxx')
+        e8.set_binfo('xxx', [], [], [], [])
         e8.set_csig('yyy')
         assert e8.get_bsig() == 'xxx', e8.get_bsig()
         assert e8.get_csig() == 'yyy', e8.get_csig()
@@ -823,7 +823,7 @@ class FSTestCase(unittest.TestCase):
         f9 = fs.File("f9")
         assert f9.get_bsig() is None, f9.get_bsig()
         assert f9.get_csig() is None, f9.get_csig()
-        f9.set_bsig('xxx')
+        f9.set_binfo('xxx', [], [], [], [])
         f9.set_csig('yyy')
         assert f9.get_bsig() == 'xxx', f9.get_bsig()
         assert f9.get_csig() == 'yyy', f9.get_csig()
@@ -831,7 +831,7 @@ class FSTestCase(unittest.TestCase):
         d10 = fs.Dir("d10")
         assert d10.get_bsig() is None, d10.get_bsig()
         assert d10.get_csig() is None, d10.get_csig()
-        d10.set_bsig('xxx')
+        d10.set_binfo('xxx', [], [], [], [])
         d10.set_csig('yyy')
         assert d10.get_bsig() is None, d10.get_bsig()
         assert d10.get_csig() is None, d10.get_csig()
@@ -1651,7 +1651,7 @@ class CacheDirTestCase(unittest.TestCase):
         SCons.Sig.MD5.collect = my_collect
         try:
             f5 = fs.File("cd.f5")
-            f5.set_bsig('a_fake_bsig')
+            f5.set_binfo('a_fake_bsig', [], [], [], [])
             cp = f5.cachepath()
             dirname = os.path.join('cache', 'A')
             filename = os.path.join(dirname, 'a_fake_bsig')
@@ -1661,7 +1661,7 @@ class CacheDirTestCase(unittest.TestCase):
 
         # Verify that no bsig raises an InternalERror
         f6 = fs.File("cd.f6")
-        f6.set_bsig(None)
+        f6.set_binfo(None, [], [], [], [])
         exc_caught = 0
         try:
             cp = f6.cachepath()
diff --git a/src/engine/SCons/Node/NodeTests.py b/src/engine/SCons/Node/NodeTests.py
index 63b945f..e9d779c 100644
--- a/src/engine/SCons/Node/NodeTests.py
+++ b/src/engine/SCons/Node/NodeTests.py
@@ -344,18 +344,34 @@ class NodeTestCase(unittest.TestCase):
         a = node.builder.get_actions()
         assert isinstance(a[0], MyAction), a[0]
 
-    def test_set_bsig(self):
-        """Test setting a Node's signature
+    def test_set_binfo(self):
+        """Test setting a Node's build information
+        """
+        node = SCons.Node.Node()
+        node.set_binfo('www', ['w1'], ['w2'], 'w act', 'w actsig')
+        assert node.bsig == 'www', node.bsig
+        assert node.bkids == ['w1'], node.bkdids
+        assert node.bkidsigs == ['w2'], node.bkidsigs
+        assert node.bact == 'w act', node.bkdid
+        assert node.bactsig == 'w actsig', node.bkidsig
+
+    def test_get_binfo(self):
+        """Test fetching a Node's build information
         """
         node = SCons.Node.Node()
-        node.set_bsig('www')
-        assert node.bsig == 'www'
+        node.set_binfo('yyy', ['y1'], ['y2'], 'y act', 'y actsig')
+        bsig, bkids, bkidsigs, bact, bactsig = node.get_binfo()
+        assert bsig == 'yyy', bsig
+        assert bkids == ['y1'], bkdids
+        assert bkidsigs == ['y2'], bkidsigs
+        assert bact == 'y act', bkdid
+        assert bactsig == 'y actsig', bkidsig
 
     def test_get_bsig(self):
         """Test fetching a Node's signature
         """
         node = SCons.Node.Node()
-        node.set_bsig('xxx')
+        node.set_binfo('xxx', ['x1'], ['x2'], 'x act', 'x actsig')
         assert node.get_bsig() == 'xxx'
 
     def test_set_csig(self):
@@ -372,11 +388,11 @@ class NodeTestCase(unittest.TestCase):
         node.set_csig('zzz')
         assert node.get_csig() == 'zzz'
 
-    def test_store_bsig(self):
-        """Test calling the method to store a build signature
+    def test_store_binfo(self):
+        """Test calling the method to store build information
         """
         node = SCons.Node.Node()
-        node.store_bsig()
+        node.store_binfo()
 
     def test_store_csig(self):
         """Test calling the method to store a content signature
@@ -907,7 +923,7 @@ class NodeTestCase(unittest.TestCase):
         n = SCons.Node.Node()
 
         n.set_state(3)
-        n.set_bsig('bsig')
+        n.set_binfo('bbb', ['b1'], ['b2'], 'b act', 'b actsig')
         n.set_csig('csig')
         n.includes = 'testincludes'
         n.found_include = {'testkey':'testvalue'}
@@ -917,6 +933,10 @@ class NodeTestCase(unittest.TestCase):
 
         assert n.get_state() is None, n.get_state()
         assert not hasattr(n, 'bsig'), n.bsig
+        assert not hasattr(n, 'bkids'), n.bkids
+        assert not hasattr(n, 'bkidsigs'), n.bkidsigs
+        assert not hasattr(n, 'bact'), n.bact
+        assert not hasattr(n, 'bactsig'), n.bactsig
         assert not hasattr(n, 'csig'), n.csig
         assert n.includes is None, n.includes
         assert n.found_includes == {}, n.found_includes
diff --git a/src/engine/SCons/Node/__init__.py b/src/engine/SCons/Node/__init__.py
index 861b554..a9581e4 100644
--- a/src/engine/SCons/Node/__init__.py
+++ b/src/engine/SCons/Node/__init__.py
@@ -205,7 +205,7 @@ class Node:
 
     def built(self):
         """Called just after this node is sucessfully built."""
-        self.store_bsig()
+        self.store_binfo()
 
         # Clear out the implicit dependency caches:
         # XXX this really should somehow be made more general and put
@@ -217,7 +217,7 @@ class Node:
             def get_parents(node, parent): return node.get_parents()
             def clear_cache(node, parent):
                 node.implicit = None
-                node.del_bsig()
+                node.del_binfo()
             w = Walker(self, get_parents, ignore_cycle, clear_cache)
             while w.next(): pass
 
@@ -241,7 +241,7 @@ class Node:
         builds).
         """
         self.set_state(None)
-        self.del_bsig()
+        self.del_binfo()
         self.del_csig()
         try:
             delattr(self, '_calculated_sig')
@@ -402,7 +402,7 @@ class Node:
                     self.implicit = []
                     self.implicit_dict = {}
                     self._children_reset()
-                    self.del_bsig()
+                    self.del_binfo()
 
         build_env = self.get_build_env()
 
@@ -495,22 +495,47 @@ class Node:
         """Set the node's build signature (based on the signatures
         of its dependency files and build information)."""
         self.bsig = bsig
+
+    def get_binfo(self):
+        """Get the node's build signature (based on the signatures
+        of its dependency files and build information)."""
+        result = []
+        for attr in ['bsig', 'bkids', 'bkidsigs', 'bact', 'bactsig']:
+            try:
+                r = getattr(self, attr)
+            except AttributeError:
+                r = None
+            result.append(r)
+        return tuple(result)
+
+    def set_binfo(self, bsig, bkids, bkidsigs, bact, bactsig):
+        """Set the node's build signature (based on the signatures
+        of its dependency files and build information)."""
+        self.bsig = bsig
+        self.bkids = bkids
+        self.bkidsigs = bkidsigs
+        self.bact = bact
+        self.bactsig = bactsig
         try:
             delattr(self, '_tempbsig')
         except AttributeError:
             pass
 
-    def store_bsig(self):
+    def store_binfo(self):
         """Make the build signature permanent (that is, store it in the
         .sconsign file or equivalent)."""
         pass
 
-    def del_bsig(self):
+    def get_stored_binfo(self):
+        return (None, None, None, None, None)
+
+    def del_binfo(self):
         """Delete the bsig from this node."""
-        try:
-            delattr(self, 'bsig')
-        except AttributeError:
-            pass
+        for attr in ['bsig', 'bkids', 'bkidsigs', 'bact', 'bactsig']:
+            try:
+                delattr(self, attr)
+            except AttributeError:
+                pass
 
     def get_csig(self):
         """Get the signature of the node's content."""