If the .do script deletes $3, don't die.

minimal/do

@@ -38,7 +38,7 @@ _do()
 			export DO_DEPTH="$DO_DEPTH  "
 			. "$PWD/$DOFILE" >"$TARGET.tmp"
 		) && 
-		mv "$TARGET.tmp" "$TARGET"
+		mv "$TARGET.tmp" "$TARGET" 2>/dev/null || touch "$TARGET"
 	else
 		echo "do  $DO_DEPTH$TARGET exists." >&2
 	fi

redo.py

@@ -134,10 +134,12 @@ def _build(t):
     log('%s\n' % relpath(t, vars.STARTDIR))
     rv = subprocess.call(argv, preexec_fn=lambda: _preexec(t),
                          stdout=f.fileno())
-    st = os.stat(tmpname)
     stampfile = sname('stamp', t)
     if rv==0:
-        if st.st_size:
+        if os.path.exists(tmpname) and os.stat(tmpname).st_size:
+            # there's a race condition here, but if the tmpfile disappears
+            # at *this* point you deserve to get an error, because you're
+            # doing something totally scary.
             os.rename(tmpname, t)
         else:
             unlink(tmpname)

t/all.do

@@ -1,2 +1,3 @@
-redo-ifchange hello yellow bellow c d
+redo-ifchange hello yellow bellow c d deltest deltest2
+
 

t/deltest.do

@@ -0,0 +1,2 @@
+# remove an empty output file
+rm -f $3

t/deltest2.do

@@ -0,0 +1,3 @@
+# delete a non-empty output file
+echo hello
+rm -f $3