Hello, Don't you think it is time to design an extensible changeset format for exchanging information about changesets between systems?
Right now I am struggling to extract full information from uncommitted Subversion changeset for uploading it for review (in Rietveld project). Rietveld code review tool was initially designed to work with Subversion, but so far it is still impossible to get complete diff of changes from SVN that reviewer can apply to its working copy and commit after review. The problem to get complete diff is twofold: 1. Subversion data for uncommited changeset is scattered and it is hard to say if it ever complete. 2. "svn diff" format is too limited. For the first part I can give an example of problem I am trying to solve currently - 'Rietveld code review data is missing files that were created as a result of "svn copy" or "svn move" operation'. If a text file is added with "svn add" - its contents will appear in "svn diff" output, but text files created as a result of "svn move" or "svn copy" operation will not. To get this missing information one need to run "svn status", check for the presence of copied or moved files (marked with "A +"), check these files are not binary, manually reconstruct change chunk for them and append missing data to the output of "svn diff". But even after that reviewer still won't be able to exactly reproduce changeset, because "svn diff" format will not contain information about source of copied or moved file. And here comes the second part. "svn diff" format doesn't record enough information to reproduce committed changeset. For example, it doesn't have data about source of copied and moved files. This is believed to be solved by "git diff" format, but it won't be a panacea either, because Subversion changesets also contain information about properties, mime types etc. It is also impossible to include binary files (if needed) or original author info (can be useful for contibulyzer), or any other information that a given VCS (Subversion in this case) is needed to completely reconstruct its own changeset. For code reviews, ideally, code review system such as Rietveld should grab the changeset, parse it and extract relevant information for reviewer (skipping or filtering non-interesting parts and giving warning about unknown parts). It should also save original or filtered changeset file to be imported and committed if review is successful. That's why extensible changeset format is required. It will not only be useful for sending changesets for review, but also for synchronizing changes with other VCSes. With new changeset format mirroring tool could automatically analyze incoming data to find Subversion related attributes to save them into repository directly and automatically save all other attributes to properties. I see this format as an XML format that resembles Atom feed, with logical order of events (i.e. file removed after it was copied etc.). Subversion already uses XML formats internally, so I logically assume that folks here possess required experience and may even have some ready pieces to work out an initial draft of such format. Please, CC. -- anatoly t.
