Tuning Github for SPL development

Branching models and operations for product engineers

Oscar DíazUniversity of the Basque Country

ONEKIN Research GroupSan Sebastian, Spain

Leticia MontalvilloUniversity of the Basque Country

ONEKIN Research GroupSan Sebastian, Spain

SPLC’15 Nashville 2015, TN

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SPL SettingEvolving SPLsFeature-Oriented SPLs

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SPL Scope of reuse

Deestral&Bosch2005: Product Derivation in Software Product Families: A Case Study

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Domain engineering development

Feature-Oriented SPLsFeature implementation =

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Application engineering development

1. Get initial feature configuration

2. Customization

3. Assemble

Customized core asset

Brand newasset

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It looks like two kinds of repositories exist

…

1 Core_Asset_Repository + N Product_Repository

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Where do we keep the assets?

VCSs

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Github highlights

More than 10 million of users

More than 24 million of repositories

Web-based Git Repository hosting service

Popular for collaborative development

"GitHub Press Info". github.com. Github. Retrieved 2015-07-23

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?A Look into a Github Repository

Repository Owner

Repository Name

User logged

Default branch

Source Code

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?A look into a Forked Repository

Cloned Source Code

All branches & commits

A link to the “original” repository

My account

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How do both repositories look like on Github?

…

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How does a core asset repository look like in Github?

Domain developer

Features implementation

Core asset repository name

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How does a Product Repository look like in Github?

Application developer Product repository name

Product assets

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The problemThe sync Challenge

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?Now, let’s have a show of hands …

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Should a product repository be obtained after a core asset repository?

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Should reusable core asset updates be propagated to existing products?

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Should product specific customizations be upgraded as core assets?

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If you answered “Yes” to any ….There is a sync challenge

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The problem: The Sync Challenge

The sync challenge implies to:

1. Create product repositories from core asset repositories along a feature configuration

2. Update product assets with newer versions available at core asset repository

3. Feedback product customizations from product repository to core asset repository

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Does Github support the sync challenge?

Fork & pull Request operate at high granularity. We want them at feature level

Fork Granularity: at repository level (branches and commit history) What if we only want a subset of the features?

Pull Requests Granularity: at branch level ( branches hold a project’s

snapshot) What if we only want the changes related to a given feature to

be propagated? What happens if my product is not reusing that feature?

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How can we tune Github to support engineers on the sync challenge?

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The solutionGitLine: a Firefox plug-in that extends Github functionality

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Github operations for the sync challenge3 OPERATIONS FOR PRODUCT ENGINEERS

1. Create product repositories from Core Asset repositories along a core asset configuration

PRODUCT FORK

2. Update product assets with newer versions from core asset repository

UPDATE PROPAGATION

3. Feedback product specific assets from product repositories to core asset repository

FEEDBACK PROPAGATION

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Product Fork operation

Product Fork ( User_Account X Core_Asset_Repository X Configuration_of_core_assets ) :: Product_Repository

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Product Fork: Accesing the Core Asset Repository

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Product Fork: Getting the feature configuration

Product Fork Update Propagation Feedback Propagation

Feature selection Configuration steps

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Behind the scenes …

… GitLine creates a new product repositoryinitialized only with the core assets of the selected features: deleting not wanted assets & branches & setting up the branching model for the user

Product Fork Update Propagation Feedback Propagation

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Product Fork: A new Product Repository

Product Fork Update Propagation Feedback Propagation

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Update Propagation Operation

Update Propagation ( User_Account X Core_Asset_Repository X Product_Repository):: Pull_Request

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Core Asset Repository has new updates

Product Fork

Update Propagation

Feedback Propagation

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Update Propagation: Enacting the operation

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Behind the scenes …

… GitLine is accessing the core asset repositoryand checks where there are newer feature versions that my product is reusing & brings them into a product’s repository dedicated branch

Product Fork

Update Propagation

Feedback Propagation

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Update Propagation pulling new versions of Core Assets

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Opening the update request: Diff view

Product Fork

Update Propagation

Feedback Propagation

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Feedback Propagation

Feedback Propagation ( User_Account X Product_Repository X customization_branch X Core_Asset_Repository ):: Pull_Request

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There is a new product specific asset

Product specific customizationWe want to feedback

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Selecting the product specific asset

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Behind the scenes …

… GitLine traverses the branch history to cherry-pick only the changes that occurred under that branch and propose them as feedback for a core asset repository feature.

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A new Feedback Pull Requestin the Core Asset Repository

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Opening the feedback request: Diff view

Product Fork Update Propagation

Feedback PropagationComparing PlayMovie Feature

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Almost reaching the end…

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What can you find in the paper?

Things I did not explained during the presentation:

A branching model for core asset repositories

A branching model for product repositories

The operational semantics for 3 sync repository operations

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A branching model for Core Asset Repository

4 main type of branches.Branch-per-purpose style

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What can you find in the paper?

Things I did not explained during the presentation:

A branching model for core asset repositories

A branching model for product repositories

The operational semantics for 3 sync repository operations

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A branching model for Product Repository

7 main type of branches.Branch-per-purpose style

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What can you find in the paper?

Things I did not explained during the presentation:

A branching model for core asset repositories

A branching model for product repositories

The operational semantics for 3 sync repository operations

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What can you find in the Web?

A realization of these operations as a Firefox plug-in: GitLine

GitLine is freely-available as a GitHub project

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https://github.com/letimome/GitLine

FORK & SEND PULL REQUEST

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http://letimome.github.io/GitLine

ASK FOR A LIVE DEMO!!

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Summary

ProblemSync DE & AE developments

ContributionBranching models for Core Asset & Product

RepositoryFormalization of three sync SPL operations

ValidationFeasibility: GitLine tool, Firefox plug-in for GitHub

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Limitations and future lines

Evaluation of the branching model & operations with practitioners

GitLine depends on Github

Provide GitLine with different composition mechanisms

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@

Contact us,leticia.montalvillo@ehu.eus

Thanks for your attention!

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Extra to illustrate operations in action …

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Product Fork Operation

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Update Propagation

Enact update propagation…

Diff=

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Feedback Propagation

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Diff=

Enact Feedback…