Migrate repository from TFS to Github

What you’ll need before you start

Name of old TFS repository
Version number within the old TFS repository you want to migrate history from (important with big, old projects)
Git-TF (see installation instructions below)
New Github repository

Install Git-TF

If you don’t already have Git-TF, you can either use Chocolatey with cinst Git-TF, or download it manually from the Git-TF project page.

Create a new Github repository

Log into Github and create a new repository with the name of project. This may be different from the old TFS name as some repository naming conventions have changed. NB. You may need someone else to do this for you if you don’t have permission.

Clone the TFS repository as a Git repository

Within your git workspace (typically, C:\Git), type the following command (and when promted use the administrator’s credentials):

git tf clone --deep http://my-tfs:8080/tfs/Tfs {src-repo} .

NB. {src-repo} is the TFS repo path, but with the / changed to \. If you fail to do this, you may get a git-tf: A server path must be absolute.

But, if the repository is too big (too many commits), then you may also do:

git tf clone --shallow --version={n} http://my-tfs:8080/tfs/Tfs  {src-repo} .
git tf pull --rebase --deep

E.g. For SAPI, the shallow command looked like:

git tf clone --version=69919 --shallow http://my-tfs:8080/tfs/Tfs  $\SAPI\Main .
git tf pull --rebase --deep

NB. If you get an error like Unable to find a required JAR: C:\ProgramData\chocolatey\lib\Git-TF\Tools\git-tf-2.0.3.20131219/lib/com.microsoft.gittf.client.clc-*.jar does not exist, follow the instructions at http://stackoverflow.com/questions/33915987/git-tf-unable-to-find-required-jar

Prepare to ‘Gitify’ and ‘NuGetify’ the project

First, copy over the following Git files from the FMP project into the new Git project folder:

.gitignore .gitattributes

Then, for the solution folder, copy over into a new .nuget folder from the FMP project:

.nuget\nuget.config

Clean the solution

Remove *.vs{aa}cc files and the packages folder.

Open the solution in Visual Studio:

Ensure it doesn’t have any links to TFS; if it does, remove them
Force a save by creating a new folder, saving the solution and then deleting the folder and re-saving the solution

Incorporating NuGet into the solution

Add the .nuget folder into the solution
Build the solution

Clean the Git repository

Run the following script to remove the packages folder from the repository:

git filter-branch --index-filter "git rm -r --cached --ignore-unmatch packages/" --prune-empty --tag-name-filter cat -- --all

Push to Github

Set the Git remote to that of the Github repository url, and then push to Github by running the following:

git remote add origin {git-repo-link}
git push origin master --force

Update the TeamCity build to use Git, rather than TFS

Go to the TeamCity project and choose Edit Project Settings
Then choose VCS Roots
For each item in the list perform the following:
Change Type of VCS to Git
Change Fetch URL to that of the Github repository (using the format git@github.com:findmypast/{repository}.git)
Change Authentication method to Uploaded Key
Change Uploaded Key to teamcity-fmp
(Click Advanced Settings if necessary)
Tick Convert line-endings to CRLF
Hit the Test connection button
Hit the Save button

Update TeamCity to restore NuGet

Within the TeamCity project choose Edit Project Settings
Then choose Build Steps

Add build step to restore NuGet

Click Add Build Step
Choose Runner type of NuGet Installer
Click Show advanced options
Set Step name to that of Restore NuGet packages
Set Path To Solution File by clicking the tree dropdown to the right and selecting it
Set Package Sources to the urls contained within .nuget\nuget.config
Click Save
Hit Reorder build steps and move the newly created step to the top of the list and click Apply