Hi,

On 17 November 2010 05:35, Michael Hope michael.hope@linaro.org wrote:

1. How easy is it to frequently merge in SVN? It used to be terrible

as you had to manually track the merges. These days can you do a 'svn merge trunk' and have it just work?

I asked Mike Meissner to answer this question. Mike is very experienced in GCC and GCC SVN branch management. I am attaching his reply.

Ira

I sent this recently to ppc64-toolchain@linux.ibm.com on how to use svnmerge to manage branches:

This script (also ~meissner/meissner/bin.sh/svnmerge) is what I use to update svn directories, such as ibm-gcc-4_5-branch. I think I originally got it from Ben E. and it may be in the contrib directory.

Typically the way I start a branch, such as my normal power7-meissner branch, I do the following: $ export TRUNK="svn+ssh://@gcc.gnu.org/svn/gcc/trunk" $ export BNAME="power7-meissner" $ export BRANCH="svn+ssh://@gcc.gnu.org/svn/gcc/branches/ibm/$BNAME" $ export SRC="$HOME/fsf-src" $ svn delete -m"delete old branch" $BRANCH $ svn copy -m"Clone new branch" $TRUNK $BRANCH $ cd $SRC $ svn co $BRANCH $ cd $BNAME $ svnmerge init $ svn update # this is sometimes needed $ svn commit -m'Create svnmerge init info' $ export REV="xxxx" # substitute subversion id for xxxxx $ echo "power7-meissner branch, based on $REV." > gcc/REVISION $ touch gcc/ChangeLog.power7 $ <edit gcc/ChangeLog.power to create initial contents> $ svn add gcc/ChangeLog.power gcc/REVISION $ svn commit -m'Add REVISION to branch'

In particular, creating GCC/REVISION allows you to tell what subversion revision the source is based against. You can find the information via: $ svn propget svnmerge-integrated

but it is a lot easier if you have a compiler tree to do gcc -v. After you do a propget, you will need to do a svn update.

In this case, I use gcc/ChangeLog.power7 to hold the ChangeLog entries local to the branch. That way I can see a summary of the changes, but not pollute the normal ChangeLog files.

To do merges, you need to make sure that all local changes are checked into the branch. Then do: $ cd $SRC/$BNAME $ svnmerge merge $ <edit gcc/REVISION and ChangeLog.power7 to indicate merge> $ <test merged files, if satisified, check them in> $ export REV="xxxx" # substitute subversion id for xxxxx $ svn update # just in case $ svn commit -m"Update to subversion id $REV"

Now, to create a patch file do, make sure the files are checked in: $ cd $SRC/$BNAME $ export PATCHFILE="$HOME/patches/mypatch.patch01" $ <make ChangeLog entries in $PATCHFILE> $ svn diff --old $TRUNK --new . -r $REV >> $PATCHFILE $ <delete ChangeLog.power7, REVISION, property changes from $PATCHFILE> $ submit patch

To see if there are changes to be merge in: $ svnmerge avail

For example on the ibm-gcc-4_5-branch, the following changes are available to be merged in: 164657-166510 when I originally wrote this message on the 9th of November, and Peter has subsequently updated the merge.

I put the folliwng in ~/.subversion/config to provide my own diff command: ### Set diff-cmd to the absolute path of your 'diff' program. ### This will override the compile-time default, which is to use ### Subversion's internal diff implementation. diff-cmd = /home/meissner/bin.sh/svndiff

Every so often, I find svnmerge misses, for example in deleting directories. It is helpful to do a diff from the mainline every so often to make sure you are not missing newly created files or still are keeping older files or just missed a change.

I'll include svndiff for the smarter svndiff command and mrm-changelog.el that looks for the ChangeLog.<name> files I use in different branches. Feel free to contact me to clarify some stuff.

-- Michael Meissner, IBM 5 Technology Place Drive, M/S 2757, Westford, MA 01886-3141, USA meissner@linux.vnet.ibm.com fax +1 (978) 399-6899 (See attached file: svnmerge)(See attached file: svndiff)(See attached file: mrm-changelog.el)