From 51bbdc6c5a280de99b4cbc2c46d78a8f0494c13c Mon Sep 17 00:00:00 2001
From: Avery Pennarun <apenwarr@gmail.com>
Date: Mon, 6 Dec 2010 03:12:53 -0800
Subject: [PATCH] If we can't find a .do file for a target, mark it as not
 is_generated.

This allows files to transition from generated to not-generated if the .do
file is ever removed (ie. the user is changing things and the file is now a
source file, not a target).
---
 builder.py | 18 +++++++++++-------
 state.py   |  6 ++++++
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/builder.py b/builder.py
index dd42154..8a8b5ba 100644
--- a/builder.py
+++ b/builder.py
@@ -58,19 +58,23 @@ class BuildJob:
             # target doesn't need to be built; skip the whole task
             return self._after2(0)
         if (os.path.exists(t) and not os.path.exists(t + '/.')
-             and not state.is_generated(t)
-             and not os.path.exists('%s.do' % t)):
-            # an existing source file that is not marked as a generated file.
-            # This step is mentioned by djb in his notes.  It turns out to be
-            # important to prevent infinite recursion.  For example, a rule
-            # called default.c.do could be used to try to produce hello.c,
-            # which is undesirable since hello.c existed already.
+             and not state.is_generated(t)):
+            # an existing source file that was not generated by us.
+            # This step is mentioned by djb in his notes.
+            # For example, a rule called default.c.do could be used to try
+            # to produce hello.c, but we don't want that to happen if
+            # hello.c was created by the end user.
+            # FIXME: always refuse to redo any file that was modified outside
+            # of redo?  That would make it easy for someone to override a
+            # file temporarily, and could be undone by deleting the file.
+            state.unmark_as_generated(t)
             state.stamp_and_maybe_built(t)
             return self._after2(0)
         state.start(t)
         (dofile, basename, ext) = _find_do_file(t)
         if not dofile:
             if os.path.exists(t):
+                state.unmark_as_generated(t)
                 state.stamp_and_maybe_built(t)
                 return self._after2(0)
             else:
diff --git a/state.py b/state.py
index de7e681..2986c15 100644
--- a/state.py
+++ b/state.py
@@ -97,6 +97,12 @@ def stamp(t):
 
 def unstamp(t):
     unlink(_stampname(t))
+    unlink(_sname('dep', t))
+
+
+def unmark_as_generated(t):
+    unstamp(t)
+    unlink(_sname('gen', t))
 
 
 def stamped(t):