Using TortoiseSVN how do I merge changes from the trunk to a branch and vice versa?

Question

I've been reading up on branching/merging with Subversion 1.5 using the excellent and free Version Control with Subversion book. I think that I understand how to use the Subversion command line client to perform the actions that I need most often, which are:

Update Branch with Changes from Trunk

From the branch's working directory run:

svn merge http://svn.myurl.com/proj/trunk

Merge Branch into Trunk

From the trunk's working directory run:

svn merge --reintegrate http://svn.myurl.com/proj/branches/mybranch

However, we are using TortoiseSVN 1.5 as our interface to Subversion. I would like to know how best to perform these operations with TortoiseSVN. The new dialog provides three different options on the main menu.

1. Merge a range of revisions
2. Reintegrate a branch
3. Merge two different trees

From what I can gather, TortoiseSVN always executes svn with the following syntax.

svn merge [--dry-run] --force From_URL@revN To_URL@revM PATH

Additionally, reintegrate a branch often fails with a message stating that some targets have not been merged and so it cannot continue, and so I had to use option #3.

My questions are:

1. How do I use TortoiseSVN 1.5 to merge changes from the trunk to a branch?
2. How do I use TortoiseSVN 1.5 to merge the branch to the trunk, with and without the reintegrate method?
3. Which of the above options should I use for each, and why?

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EDIT

Through "dry run" testing I have found that the command line Subversion operation

svn merge http://svn.myurl.com/proj/trunk

is analogous to option #1 (Merge a Range of Revisions) in TortoiseSVN, as long as I leave the revision range blank.

Answer 1

You should use "merge a range of revision".

To merge changes from the trunk to a branch, inside the branch working copy choose "merge range of revisions" and enter the trunk URL and the start and end revisions to merge.

The same in the opposite way to merge a branch in the trunk.

About the --reintegrate flag, check the manual here: http://tortoisesvn.net/docs/release/TortoiseSVN_en/tsvn-dug-merge.html#tsvn-dug-merge-reintegrate

Answer 2

The behavior depends on which version your repository has. Subversion 1.5 allows 4 types of merge:

1. merge sourceURL1[@N] sourceURL2[@M] [WCPATH]
2. merge sourceWCPATH1@N sourceWCPATH2@M [WCPATH]
3. merge [-c M[,N...] | -r N:M ...] SOURCE[@REV] [WCPATH]
4. merge --reintegrate SOURCE[@REV] [WCPATH]

Subversion before 1.5 only allowed the first 2 formats.

Technically you can perform all merges with the first two methods, but the last two enable subversion 1.5's merge tracking.

TortoiseSVN's options merge a range or revisions maps to method 3 when your repository is 1.5+ or to method one when your repository is older.

When merging features over to a release/maintenance branch you should use the 'Merge a range of revisions' command.

Only when you want to merge all features of a branch back to a parent branch (commonly trunk) you should look into using 'Reintegrate a branch'.

And the last command -Merge two different trees- is only usefull when you want to step outside the normal branching behavior. (E.g. Comparing different releases and then merging the differenct to yet another branch)

Answer 3

Take a look at svnmerge.py. It's command-line, can't be invoked by TortoiseSVN, but it's more powerful. From the FAQ:

Traditional subversion will let you merge changes, but it doesn't "remember" what you've already merged. It also doesn't provide a convenient way to exclude a change set from being merged. svnmerge.py automates some of the work, and simplifies it. Svnmerge also creates a commit message with the log messages from all of the things it merged.