Team Foundation Server - Moving Source with History

Question

I was wondering what the best approach might be in moving source code, with history, from one Team Project to another Team Project. I am not concerned with work items, reporting, or SharePoint sites, as the system we are going to be restoring from did not use these functionalities. The reason for wanting to move to a different Team Project also is driven by the fact that the original implementation (being restored from a backup that was maintained by a third party) were using a third-party process template that we do not wish to use going forward. We want to start utilizing work item tracking and reporting after the migration is complete.

The TFS Integration Platform seems to be one likely scenario. It can be used to change the process template, according to the documentation. However, I was curious if the tf.exe move syntax might work? Something like:

tf.exe move $/ProjectA $/ProjectB

It is my understanding that this command operates much like a rename operation, whereas moving with the "Move" context menu item in Source Control Explorer is more like a delete and add operation. Also, would the tf.exe move path actually associate the code under the folders with the appropriate Team Project, assuming that $/ProjectA is the root source control folder for one project and $/ProjectB is the root source control folder for the other? The key is to be able to preserve the history, if possible.

Any advice or tips would be greatly appreciated!

Edit - Could branching to another project handle this scenario - much like Microsoft discusses in the Branching Guidance documentation? I think that this could be the answer, since the history would likely be preserved with the branch. However, I do not have access to a Team Foundation Server 2008 instance at the moment to test it.

Answer 1

Move and Rename are aliases. There is absolutely no difference, in any version of TFS, from the command line or the UI.

Both of them preserve history. At least in 2005/2008, you keep the same physical item in the VersionedItem table no matter how often or how drastically the name and/or parent path changes. There is actually no way to get a "fake" rename (delete + add) without a lot of manual work on your part.

However, while this versioning model is very pure in a theoretical sense, it has some practical gotchas. Because different items can occupy the same name at different points in time, TFS needs the full name + version to uniquely identify any inputs you send it. Normally you don't notice this restriction, but once have you renamed items in the system, if you say tf [doSomething] $/newname -version:oldversion then it will get confused and either throw an error or operate on an item you may not have intended. You have to be careful to pass valid combinations (newname+newversion or oldname+oldversion) to ensure commands behave the way you want.

TFS 2010 changes the story somewhat: it's a branch+delete under the covers, causing the itemID to change. Even so, everyday commands like Get and History are "faked" very well; old clients are about 95% compatible. The advantage is that when you have multiple renames in the system and path-based item lookups start to become ambiguous as alluded to above, the server will simply accept the name you specify and run with it. This improves overall system performance and eliminates several traps that unfamiliar users often fell into, at the cost of not being quite as flexible and not preserving history with 100% precision (eg when there are name collisions during a Merge of two branches).

Returning to the problem at hand...

It's not as simple as saying tf rename $/projectA $/projectB. Top level folders in the source control tree are reserved for the Team Project Creation Wizard; you can't run standard tf commands against them. What you need is a script like:

Get-TfsChildItem $/ProjectA |
    select -Skip 1 |  # skip the root dir
    foreach {
        tf rename $_.serveritem $_.serveritem.replace("$/ProjectA", "$/ProjectB")
    }

[of course, you can do it by hand if there aren't too many children under $/ProjectA]

As far as the gotchas I mentioned, I'll elaborate on one right now since looking up old history seems very important to you. Once you checkin the rename, tf history $/ProjectA/somefile.cs will NOT work. By default, tf commands assume version = "latest." Any of these alternatives will the full history you want:

• tf history $/ProjectA/somefile.cs;1234 where changeset 1234 was before the move
• tf history $/ProjectB/somefile.cs;5678 where changeset 5678 was after the move. Or you could just omit the version.

A final alternative for completeness & debugging purposes:

• tf history $/ProjectA/somefile.cs -slotmode. You will only see the changes that happened prior to the move; however you'll also see the history of any other items that may have lived in the $/ProjectA/somefile.cs "slot" prior to or subsequent to the item you moved underneath B.

(In TFS 2010, "slot mode" is the default behavior; there's an -ItemMode option to request that your lookup be traced across history like it was 2008 rather than path-based.)

EDIT - no, branching is not a great alternative. While branching does leave enough metadata in the system to trace the full history to & from ProjectB, it's not terribly user friendly in 2008. Plan to spend a lot of time learning the tf merges command (no UI equivalent). 2010 dramatically improves your ability to visualize changes across multiple branches, but it's still not the clean unified experience you'd get from a Rename.