Add a --debug=pdb option to run SCons under the Python debugger.

2 files changed, 17 insertions, 1 deletions

diff --git a/src/CHANGES.txt b/src/CHANGES.txt
index f381241..05c4b81 100644
--- a/src/CHANGES.txt
+++ b/src/CHANGES.txt
@@ -63,6 +63,8 @@ RELEASE 0.04 -
     and updating multiple targets in a single Task.  Simplify the
     interface between Task and Taskmaster.
 
+  - Add a --debug=pdb option to re-run SCons under the Python debugger.
+
   From Steve Leblanc:
 
   - Add var=value command-line arguments.
diff --git a/src/engine/SCons/Script/__init__.py b/src/engine/SCons/Script/__init__.py
index 12a22f4..0416b62 100644
--- a/src/engine/SCons/Script/__init__.py
+++ b/src/engine/SCons/Script/__init__.py
@@ -361,7 +361,21 @@ def options_init():
 
     def opt_debug(opt, arg):
         global print_tree
-        if arg == "tree":
+        if arg == "pdb":
+            if sys.platform == 'win32':
+                lib_dir = os.path.join(sys.exec_prefix, "lib")
+            else:
+                lib_dir = os.path.join(sys.exec_prefix,
+                                       "lib",
+                                       "python" + sys.version[0:3])
+            args = [ sys.executable, os.path.join(lib_dir, "pdb.py") ] + \
+                     filter(lambda x: x != "--debug=pdb", sys.argv)
+            if sys.platform == 'win32':
+                ret = os.spawnve(os.P_WAIT, cmd_interp, args, env)
+                sys.exit(ret)
+            else:
+                os.execvpe(args[0], args, os.environ)
+        elif arg == "tree":
             print_tree = 1
         else:
             sys.stderr.write("Warning:  %s is not a valid debug type\n"