track-tags: write all tag changes to a file The tag changes information we compute is now written to disk. This gives hooks full access to that data. The format picked for that file uses a 2 characters prefix for the action: -R: tag removed +A: tag added -M: tag moved (old value) +M: tag moved (new value) This format allows hooks to easily select the line that matters to them without having to post process the file too much. Here is a couple of examples: * to select all newly tagged changeset, match "^+", * to detect tag move, match "^.M", * to detect tag deletion, match "-R". Once again we rely on the fact the tag tests run through all possible situations to test this change.