Using Version Control in Studio Pro

Introduction

This reference guide describes how to use version control in Mendix Studio Pro. The theory behind how version control works in Mendix, and a definition of the concepts can be found in Version Control.

Starting an App with Version Control

To start a new app with version control do the following:

1. In the Open App dialog box, click Create New App, or select File > New App.
2. Select the starting point – an app template.
3. In the App Settings dialog box, set Enable online services to Yes. This option creates a Team Server repository and a Mendix Portal app.
4. Choose Repository type – SVN or Git.
5. Change the App directory, or leave the default suggested by Studio Pro.
6. Click Create app.

The app is created on the Team Server, and a working copy is created in the App directory. This is opened in Studio Pro so that you can start working immediately.

Joining an App

If there is already a Team Server-enabled app, you can be invited to join it (see Team).

Once you are a team member, providing you have been given a role with sufficient rights, you can work on the app by doing the following:

1. Choose Open App in Studio Pro.
2. Choose your app from the list of the Open App dialog box.
3. Click Open in Studio Pro.

The app will be downloaded from the Team Server and opened in Studio Pro.

Day-to-Day Development

Let us say you have a working copy of an app on disk. You make changes to the app and save them. Saved changes are not immediately visible to others. The documents, folders, and modules which have been changed can be identified by looking at the status.

When you are happy with a set of changes, you commit them to the repository. Others can then choose to update/pull and retrieve those changes.

You can update/pull your working copy with changes committed by others.

You can also see a history of all the changes which have been committed, no matter who committed them.

Status

The status of your app is a summary of all the changes in your working copy when compared with the original. Studio Pro shows the status both in the App Explorer and in the Changes pane.

The App Explorer shows an icon in front of items (documents, folders, and modules) that are changed in some way. The different icons indicate the different kinds of changes which have been made.

Icon	Meaning
	Nothing happened to this item. It is unchanged with the respect to the original.
	You modified this item (as in, document, folder or module).
	You added this item.
	You moved this item to another position in the app tree.
	You deleted this item.
	You and somebody else made conflicting changes to this item. For more information, see the Dealing With Conflicts section below.

For example, say that the microflow ChangePassword has been modified. Also a new folder called ‘Flows’ was added and all microflows were moved inside this folder. The folders and modules containing changes will be depicted with a yellow icon, and the microflows which have been moved have a blue icon. This helps you to quickly see where in the app the changes are.

You can see the same information in the Changes pane. In this case there is an entry for each change to an item. If a document is both modified and moved there are two lines for that document. The pane also shows items that were deleted, something the app explorer cannot do.

Committing

Sending changes to the repository is called committing. The idea is that you commit small, consistent pieces of work to the repository. Mendix recommends committing your changes often. Preferably, the versions in the repository are always error-free, Studio Pro will warn against committing while there are errors in your app.

To commit your changes, click the Commit button in the Changes pane, or choose the Version Control > Commit… menu item.

In general, it is a good idea to commit after implementing one feature or fixing one bug. By committing often, your work is integrated with the work of others regularly. The benefits of committing include the following:

• If any conflicts arise, the changes are still fresh in your mind
• Revisions are easier to understand
• If you ever need to revert something, you can revert a small chunk of work

Committing results in a new revision in the repository. You can add the following information in Studio Pro when you perform a commit, and this will be attached to the newly created revision:

• A textual message. This should be a summary of the changes you made

• A list of Mendix Portal stories that relate to the commit. A small commit will probably relate to one story. Studio Pro shows stories that are in the current Sprint and do not have a status of Done. Adding the story to the commit will not change the state of the Mendix Portal story. Setting the status to ‘Done’ must be done manually and depends on your definition of done.

  

Studio Pro also attaches some information automatically:

• The person who committed (the author)
• The date and time of the commit
• The list of changed documents, folders, and modules along with the type of the change (for example modify or add)
• The version of Studio Pro that was used to commit

If you also changed Java source code, added widgets or made other changes that affect files other than the app file you will see a Changes on disk tab page that shows you what disk changes you are about to commit.

Committing is only allowed if your working copy is up to date with the repository. If someone else committed a change since the last time you updated/pulled, you will have to update/pull first. This is because the revision you create with the commit should incorporate both your changes and the changes by the other person. Updating will combine the latest changes in the repository with your changes. After reviewing the result, and fixing any conflicts, you can commit again.

Pushing

Pushing is sending your local changes to the Team Server. After committing you need to push the committed changes if you want them to be accessible to others. By default, this is done when committing, but it is possible to wait for this step until later.

To push changes, select Version Control > Push or make sure that the Also push changes to the remote server setting is set to Yes in the Commit dialog box, this way changes are pushed automatically when you commit them:

Updating/Pulling

Updating (SVN terminology) or pulling (Git terminology) retrieves the latest changes from the repository. You need to do this to incorporate any changes made by others that are not yet in your working copy before you can commit your changes to the repository. It is advisable to frequently update so that the number of changes you retrieve is small.

To update the working copy of your app, click Update (for SVN) or Pull (for Git) in the Changes pane, or choose the Version Control > Update/Pull menu item.

Changes you receive from the repository when updating/pulling are combined with the changes you have made to your working copy (if any). Afterwards, your working copy will contain both your changes and the changes you received. As part of the update/pull, the original of your working copy is updated as well.

For example, if the last time you updated/pulled you received all changes up to and including revision N, this means that the original for your working copy is revision 40. Since you started making changes to your working copy, other people on your team have made another four commits (X, Y, and Z). If you now update/pull, you will receive those changes and Z will be the new original to which your changes are compared.

Usually, combining your changes with the latest revision from the repository will be done automatically. For example, one person may add a page while you are changing a microflow. If the changes are too close, however, a conflict can arise. For example, if one of your team has changed the properties of the same data view which you have also changed. You will have to resolve such conflicts before you can commit. See the Dealing With Conflicts section, below, for information on how to do this.

If your team is committing often you will have to update/pull often. Frequent updating/pulling has the benefit that you receive fewer changes with each update/pull, so integrating those changes with your work is easier.

History

The history of the app is a list of all revisions that have been committed. To view the history of the app, click the History button in the Changes pane, or choose the Version Control > History menu item.

The revisions are shown in reverse chronological order (newest is at top of list). The history dialog shows you revision number, date, time, author and message of each revision.

Select a revision to see additional details such as related stories, changed documents, Studio Pro version and changes on disk. Icons summarize the kinds of changes that happened in the app.

Reverting Changes

Changes that have not yet been committed can be reverted. Say, for example, that you have made a lot of changes to a page and you are not happy with the result. You can revert the page to the original: that is, the state of the page before you started making changes.

Deletes of documents, folders, and modules can also be reverted. This will bring them back into the app. Note that you will get back the latest version you have committed. For example, if you commit, make some changes to a microflow, and then delete the microflow, reverting the delete will give you the microflow without the changes that you made.

You can revert changes in the Changes pane, from Version Control > Revert All Changes, or from the right-click menu on the document you want to revert.

Dealing With Conflicts

If you update/pull your app and the changes cannot be merged automatically you will receive a message telling you there are conflicts. A conflict arises when two changes cannot be combined.

There are two different sorts of conflict:

• Document conflicts
• App conflicts

Resolving a Document Conflict

Two changes in the same document that are really close to each other can cause a document conflict. For example, two people both change the properties of the same element on the page. The document will be marked as conflicted in the Changes pane. Conflicts have to be resolved before you can commit again.

For more information on resolving document conflicts see New Merge Algorithm with Fine-Grained Conflict Resolution and Changes Pane.

Resolving an App Conflict

App conflicts are conflicts are conflicts at the level of the app. There are two cause for app conflicts:

1. One person deletes a document and the other makes a change inside that document.
2. Both people move a document but to different places in the app tree.

The involved document is marked as conflicted and you can see the reason in the details column of the Changes pane.

You can resolve an app conflict by choosing Tasks > Use mine or by deleting the involved documents or folders.

Using Branches

A repository can contain a number of development lines. Each development line offers independent development from the other development lines. In the simple case there is just one development line called the main line (called ’trunk’ in subversion). All development then happens inside that one line.

It is often convenient to have more than one development line. For example, one development line for fixing bugs in the currently deployed version of your app and another line where you develop new functionality. If you then find a bug in the deployed version you can fix it in the corresponding development line irrespective of the state of the development line where new functionality is developed. See Version Control for more information about branches.

When to Use a Branch

Patching a Deployed Application

If you want to add some functionality to a deployed application or you want to fix a bug in it, you can do so without interfering with other development.

1. Determine the version of the deployed application. This information is in the Mendix Portal. Alternatively, you can find the version in the metadata.json file in the model subfolder of your deployment package (mda) archive. For example, "ModelVersion": "1.0.0.16"

2. Choose Version Control > Manage Branch Lines… and create a branch based on the tag with the that version number as its name.

   

3. Add the functionality or fix the bug in this newly created branch.

4. Testing that things work as intended.

5. Create a new deployment archive with a higher version number (increase patch or minor version).

Developing a New Feature Independently

Another reason for creating a branch is to develop a big new feature without interfering with other development. This gives you the freedom to commit a half-implemented feature, possibly even with errors, while other people can still commit and update/pull on the main line. Without using a branch line, you would have to constantly make sure that your app is error free and does not break other parts of the system.

Firstly, select Version Control > Manage Branch Lines… and create a branch from a revision of the main line.

Now work on the branch until the feature is done and commit the completed work.

When you want to merge the whole branch back to the main line to integrate the feature there. Do the following:

1. Open the main line.
2. Choose Version Control > Merge changes here.
3. Select Merge feature branch option.
4. Click Merge.
5. Resolve any conflicts and errors.
6. Commit the new feature to the main line.

You can delete the branch after merging it back, if you want.

Working with Branches in Studio Pro

Branching

Development lines other than the main line are called branch lines. Our advice would be to develop new features in the main line and to use branch lines for fixing bugs in versions that have been deployed. This is the scenario Studio Pro makes easy but other scenarios for more complex apps are supported as well.

You can create branch lines from the Branch Line Manager which you can find at Version Control > Manage Branch Lines….

Merging

If you have multiple development lines, you sometimes want to port changes from one development line to another. For example, the fix that you made in a branch line for the production version should also be applied to the new 2.0 version you are developing in the main line. You can, of course, do this by hand but Studio Pro can also help you by merging changes from one development line to another.

Merging is always done while you have a working copy open. The merge will result in extra local changes in that working copy. It is advisable to commit local changes first before merging extra changes into a working copy. Otherwise, the uncommitted local changes and the changes caused by the merge will be combined and it is very hard to untangle them if you are unhappy with the merge. Studio Pro will warn you if you have uncommitted changes.

Select Version Control > Merge Changes Here, select the option available for the version control you are using:

• For SVN, Port fix, Merge feature branch, and Advanced merge options are available
• For Git, Port fix and Merge feature branch options are available

For more information on merge settings, see Merge Dialog.

Reverse Merging

Reverting changes works for changes that have not been committed yet. Changes that have been committed can never be deleted. However, you can apply the changes ‘in reverse’ and commit that. This feature is called ‘Reverse merging’ in Studio Pro.

Choose Version Control > Reverse Merge Changes…

For SVN, you can choose a range (Start revision and End revision):

For Git, reverting changes is done with one commit at a time. If you want to revert multiple commits, you can do that by reverting the latest commit, then the previous one, and so on.

After a reverse merge the app will look like the changes never happened; if you ‘reverse merge’ the adding of a page, the page will be deleted locally. Just like when you are doing a normal merge, conflicts can arise. In the example, if later commits change the added page, the reverse merge will result in a conflict. After resolving any problems, you can commit the results to the repository.

Replacing the Main Line with a Branch Line

There are two methods for fully replacing your main line with a branch line.

The first method is to merge the entire branch line into the main line, essentially replacing the main line contents with the branch line contents). This works as long as the branch line is up to date with the main line (to avoid conflicts). To do this, follow these steps:

1. Select Version Control > Merge Changes Here > Merge feature branch.
2. Select the branch to merge into the main line.

The second method should be used if the first method is not possible for some reason and you want to “overwrite” the main line with your branch line. For this method, you must follow these steps:

1. Check out both the main line and the branch line locally.
2. Overwrite all the files in the main line app directory with those of the branch line (except for the .svn directory).
3. Commit your changes using Studio Pro.
4. Reopen the main line app in Studio Pro only after overwriting the files.

Merging Using Git in the Command Line

For merging .mpr files using Git in the command line to work, it is necessary to attach mx.exe merge to Git as a driver.

When doing a git merge operation on two branches in the command line, Git attempts to merge the binaries of .mpr files, which does not work. You need to apply Studio Pro merge algorithm and that is where mx.exe as a driver is needed.

Navigate to the .gitconfig file in C:/Users/[USER_NAME] and add the following:

[core]
  attributesfile = ~/.gitattributes
[merge "custom"]
  name = custom merge driver for specific files
  driver = [MX.EXE_PATH] merge %O %A %B

Where [MX.EXE_PATH] should be replaced by the mx.exe path with only forward slashes pointing to a drive using /C/ instead of C:/.

You can also configure the Git driver locally per repository using the following commands:

git config merge.custom.name "custom merge driver for specific files"
git config merge.custom.driver "[MX.EXE_PATH] merge %O %A %B"

After setting up the driver either locally or globally, create a .gitattributes file in the same folder with the following contents:

*.mpr merge=custom

Save the files and now when git merge is run and it involves .mpr files, the mx.exe merge will run Studio Pro merge algorithm before Git finishes the merge.

Versioning an App Deployed to the Cloud

Deploying Locally

While developing you can deploy and run your app on your local machine by clicking the menu item Run > Run Locally. This allows you to test the app as it currently is stored on your local machine.

Deploying Your Working Copy

When you deploy to the cloud, you can choose to use the version of the app stored on your local machine, the working copy and deploy that to the default environment. If you are using the Mendix Cloud, or other partner cloud (SAP BTP, for example), click Publish to commit the version of the app stored on your local machine and deploy that to the default environment.

Choosing a Specific Development Line and Revision

It is also possible to choose a specific development line and revision to deploy to the default environment, or to create a package from.

In this case, Studio Pro will create a fresh checkout of the chosen revision. This means that any team member can always recreate this version of the deployment package. In other words, Studio Pro does not rely on your local files for creating a versioned deployment package.

When it creates the package, Studio Pro will also create a tag representing this version of your app. If you want to make modifications to this version later, independently of other development which has taken place, you can create a branch based on this tag. The name of the tag is a version number that you choose.

Deploying a Specific Version to a Mendix Licensed Cloud Node

If you are using Mendix Cloud you can choose App > Deploy to Licensed Cloud Node to deploy a specific version.

Creating a Deployment Package from a Specific Version

If you are using a different hosting environment, you create a deployment package using the menu item App > Create Deployment Package.

Working Outside Studio Pro

Studio Pro takes care of some file management automatically. If you add or remove custom widgets they are automatically added or removed from version control, too. Some files and directories (for example, deployment and releases directories) are automatically ignored so that they are not committed to version control.

We advise you to always commit and update/pull inside Studio Pro because in this way useful metadata is added to your revisions. Studio Pro has ways to recover from external updates or merges but it is best to not depend on that.

External Tools

If you are doing more advanced changes to files, like adding Java actions or resources to your app, you will have to install a separate tool on your computer and perform some operations yourself. When using SVN, use TortoiseSVN https://tortoisesvn.net/. When using Git, use TortoiseGit https://tortoisegit.org/. Both can be downloaded for free.

Authenticating to Team Server

When using external tools, you might be asked to authenticate separately to Team Server.

Connecting to Git is done via a personal access token (PAT). For information on how to create a PAT, see the Personal Access Tokens section of Mendix Profile.

You need to use the following credentials:

• URL: https://git.api.mendix.com/<your AppID>.git
• Username: your Mendix account username (alternatively, you can use the word pat as your username)
• Password: the personal access token you created

Connecting to SVN is done with your Mendix credentials:

• URL: https://teamserver.sprintr.com/<your AppID>/

• Username: your Mendix account username

• Password: your Mendix account password

  If you are using BYOIDP, direct access to Team Server is no longer possible. For more information, see the in the BYOIDP and Team Server section Set Up an SSO (BYOIDP) .

Adding Files and Directories

If you add files or directories or delete files using Windows Explorer, Studio Pro automatically adds or deletes these from version control, too.

Make sure you use the Export feature of TortoiseSVN/TortoiseGit if you are copying a directory that is already under version control in your app.

Deleting Files and Directories

If you delete a file from your app, Studio Pro will automatically also delete it from the Team Server.

If you are using SVN and want to delete a whole directory, you have to use the delete command of TortoiseSVN. You can execute this command by right-clicking the directory and choosing TortoiseSVN > Delete.

When using Git, a folder is no longer be tracked if all the files in the folder are removed.

Branching and Deploying

If you perform branching outside of Studio Pro, you will not be able to immediately deploy to Mendix Cloud. That is because Studio Pro adds metadata about the Mendix version of your app to each revision when you commit or create a branch, which is needed by the Mendix Cloud deployment. Branching outside of Studio Pro means that metadata is missing from your branch, thus your app cannot successfully be deployed.

To fix this, make a small commit on your branch in Studio Pro (for example, changing a documentation field). Studio Pro will then add the metadata that Mendix Cloud deployment requires, and you will be able to deploy your app.

Reverting Accidental Studio Pro App Model Upgrade

When working in different apps with different Studio Pro versions, you may one day find yourself with an app model upgraded and committed to a newer Studio Pro version, while the rest of your team is not yet ready to upgrade.

To revert this version upgrade of the app model, follow these steps, using either TortoiseGit or TortoiseSVN depending on your repository type:

1. Inform your team of the situation and prevent them from making further commits.
2. Close Studio Pro.
3. In Windows Explorer, go to your main app directory.
4. Right-click the directory and select Tortoise(Git/SVN) > Show log.
5. Find the latest revision that was in the desired Studio Pro version.
6. When using TortoiseGit, select all revisions up to but excluding the desired revision. Right-click and select Revert changes by these commits, then confirm and click Yes.
7. When using TortoiseSVN, right-click that the desired revision, select Revert to this version, confirm, and click OK.
8. Back in Windows Explorer, right-click the folder again, select TortoiseSVN > Commit, enter your commit message, and click OK.
9. Start the desired Studio Pro version and download the app from Team Server.
10. Check that everything is okay in your app.
11. Inform your team that they need to do a fresh checkout of the app or run TortoiseSVN > Update on their app folder before opening the app in the desired Studio Pro version again.

Read More

• Advanced Branching and Merging Strategies