Overridden files were accidentally getting reclassified as static.

This is relatively harmless, since we treat them *almost* identically,
except that we print a warning for overridden files to remind you that
something fishy is going on.

Add a test for the actual warning message to ensure it is printed.  (I
don't like tests for specific warning messages, but it was necessary in
this case.)

redo/builder.py

@@ -170,7 +170,8 @@ class _BuildJob(object):
             # to produce hello.c, but we don't want that to happen if
             # hello.c was created by the end user.
             debug2("-- static (%r)\n" % t)
-            sf.set_static()
+            if not sf.is_override:
+                sf.set_static()
             sf.save()
             return self._finalize(0)
         sf.zap_deps1()

t/350-deps/all.do

@@ -1,2 +1,2 @@
 redo test1 test2 ifchange-fail overwrite gentest doublestatic \
-	basic/test
+	basic/test override/all

t/350-deps/clean.do

@@ -1,3 +1,3 @@
-redo basic/clean
+redo basic/clean override/clean
 rm -f *~ .*~ *.count t1a overwrite overwrite[123] \
 	genfile2 genfile.log static.log

t/350-deps/override/.gitignore

@@ -0,0 +1,4 @@
+a
+b
+*.log
+stamp

t/350-deps/override/a.do

@@ -0,0 +1 @@
+echo hello-a >$3

t/350-deps/override/all.do

@@ -0,0 +1,34 @@
+exec >&2
+rm -f a b *.log stamp
+
+echo 1 >stamp
+redo b
+[ "$(cat b)" = "hello-a-1-b" ] || exit 11
+
+../../flush-cache
+echo 2 >stamp
+redo-ifchange b
+[ "$(cat b)" = "hello-a-1-b" ] || exit 21  # a unchanged; b not redone
+
+. ../../skip-if-minimal-do.sh
+
+# Unfortunately the test below depends on the specific wording of the
+# "override" warning message, of the form:
+#    redo: a - you modified it; skipping
+# That's because this is specifically a test that the warning message
+# gets generated.  I added that test because (of course) when we didn't
+# test it, the warning message accidentally got broken.  Oops.  If you
+# rephrase the message, you'll have to also change the test.
+
+../../flush-cache
+echo 3 >stamp
+echo over-a >a
+redo-ifchange b >$1.log 2>&1
+[ "$(cat b)" = "over-a-3-b" ] || exit 31  # a overwritten, b redone
+grep "a - " "$1.log" >/dev/null || exit 32  # expected a warning msg
+
+../../flush-cache
+echo 4 >stamp
+redo-ifchange b >$1.log 2>&1
+[ "$(cat b)" = "over-a-3-b" ] || exit 41  # a not changed, b not redone
+grep "a - " "$1.log" >/dev/null || exit 42  # still expect a warning msg

t/350-deps/override/b.do

@@ -0,0 +1,2 @@
+redo-ifchange a
+printf '%s-%s-b\n' "$(cat a)" "$(cat stamp)" >$3

t/350-deps/override/clean.do

@@ -0,0 +1 @@
+rm -f *~ .*~ stamp *.log a b