Webrev lets you create comparisons based on directly specified file lists, it
doesn't even need the sources to be in an SCM. This means we can create
webrevs between arbitrary directories, as long as we spell everything out by
hand.
Let's say you're importing cat(1) from a 3rd party.
You make your changes in usr/src/cmd/cat/, and we ask that you show us
what you changed compared to the upstream source, as well as compared to our
sources.
Create a file list like this
CODEMGR_WS=/path/to/your/workspace CODEMGR_PARENT=/path/to/upstream/source usr/src/cmd/cat/cat.c <path to cat.c relative to CODEMGR_PARENT> usr/src/cmd/cat/util.c <path to util.c relative to CODEMGR_PARENT>
and run webrev -o upstream-webrev file.list it's important, due to the fragility of webrev, that the command be run from a directory not under the control of an SCM.
Webrev will create a webrev showing files being renamed from their path in the original source to their path in our source, and diffs between the two sources, as if both were part of the same source tree.