New debug option --debug=duplicate to debug Variant-dir duplication

3 files changed, 10 insertions, 1 deletions

diff --git a/src/engine/SCons/Node/FS.py b/src/engine/SCons/Node/FS.py
index bb49f95..86649f3 100644
--- a/src/engine/SCons/Node/FS.py
+++ b/src/engine/SCons/Node/FS.py
@@ -56,6 +56,7 @@ import SCons.Warnings
 from SCons.Debug import Trace
 
 do_store_info = True
+print_duplicate = 0
 
 
 class EntryProxyAttributeError(AttributeError):
@@ -2787,6 +2788,8 @@ class File(Base):
 
     def _rmv_existing(self):
         self.clear_memoized_values()
+        if print_duplicate:
+            print "dup: removing existing target %s"%self
         e = Unlink(self, [], None)
         if isinstance(e, SCons.Errors.BuildError):
             raise e
@@ -2827,6 +2830,8 @@ class File(Base):
 
     def do_duplicate(self, src):
         self._createDir()
+        if print_duplicate:
+            print "dup: relinking variant '%s' from '%s'"%(self, src)
         Unlink(self, None, None)
         e = Link(self, src, None)
         if isinstance(e, SCons.Errors.BuildError):
@@ -2860,6 +2865,8 @@ class File(Base):
                     else:
                         # The source file does not exist.  Make sure no old
                         # copy remains in the variant directory.
+                        if print_duplicate:
+                            print "dup: no src for %s, unlinking old variant copy"%self
                         if Base.exists(self) or self.islink():
                             self.fs.unlink(self.path)
                         # Return None explicitly because the Base.exists() call
diff --git a/src/engine/SCons/Script/Main.py b/src/engine/SCons/Script/Main.py
index 0513e41..0e029b5 100644
--- a/src/engine/SCons/Script/Main.py
+++ b/src/engine/SCons/Script/Main.py
@@ -656,6 +656,8 @@ def _set_debug_values(options):
         options.tree_printers.append(TreePrinter())
     if "prepare" in debug_values:
         SCons.Taskmaster.print_prepare = 1
+    if "duplicate" in debug_values:
+        SCons.Node.FS.print_duplicate = 1
 
 def _create_path(plist):
     path = '.'
diff --git a/src/engine/SCons/Script/SConsOptions.py b/src/engine/SCons/Script/SConsOptions.py
index fc5f08d..3066c65 100644
--- a/src/engine/SCons/Script/SConsOptions.py
+++ b/src/engine/SCons/Script/SConsOptions.py
@@ -596,7 +596,7 @@ def Parser(version):
         "tree"          : '; please use --tree=all instead',
     }
 
-    debug_options = ["count", "explain", "findlibs",
+    debug_options = ["count", "duplicate", "explain", "findlibs",
                      "includes", "memoizer", "memory", "objects",
                      "pdb", "prepare", "presub", "stacktrace",
                      "time"] + list(deprecated_debug_options.keys())