General

Mastering Git Rerere: Solving Repetitive Merge Conflicts with Ease

Mattia Magi

Published Jan 5, 2024

Updated Jan 8, 2024

4 min read

Mastering Git Rerere: Solving Repetitive Merge Conflicts with Ease

Introduction:

Git, the popular version control system, has revolutionized how developers collaborate on projects. However, one common pain point in Git is repetitive merge conflicts. Fortunately, Git provides a powerful and not-so-well-known solution called git rerere (reuse recorded resolution) that can save you time and effort when resolving conflicts. In this blog post, we will explore how to configure and use git rerere, and demonstrate its effectiveness in solving merge conflicts.

Understanding Git Rerere:

Git rerere is a feature that allows Git to remember how you resolved a particular merge conflict in a particular file and automatically apply the same resolution in the future. It works by recording the conflict resolution in a hidden directory called .git/rr-cache. This way, when Git encounters the same conflict in the same file in the future, it can reuse the recorded resolution, saving you from manually resolving the conflict again.

Configuring Git Rerere:

Before using git rerere, you need to enable it in your Git configuration; only once git rerere has been enabled, Git will start recording and remembering resolved conflicts.Open your terminal and run the following command:

git config --global rerere.enabled true

This command enables git rerere globally, making it available for all your repositories. You can also enable it per-repository by omitting the --global flag.

How to use it:

Let's start with a really easy example, then describe a couple of use cases.

We have merged a branch (branch-one) into our main, and we are working on two different features in two different branches (branch-two and branch-three). We need to rebase our branches with main, so we start with

git checkout branch-two
git rebase main

It turns out that there are some conflicts on App.tsx file:

We solve all the conflicts and finish with the rebase and push. As you can see, there are an extra line in the rebase output message that says:

This means that thanks to rerere option enabled, we have saved in our project's .git/rr-cache this resolution for this particular conflict.

Now let's switch branches into branch-three cause we want to rebase on main also this one:

git checkout branch-three
git rebase main

It seems that we have the same conflicts here too, but this time, on the rebase output message, we can read:

The conflict has been resolved automatically; if we check our IDE, we can see the change (and check if it works for us) ready to be committed and pushed with the same resolution we manually used in the past rebase.

The example above focuses on a rebase, but of course, git rerere also works for conflicts that came out from a merge command.

Here are a couple of real-life scenarios where git rerere can save the day:

Frequent Integration of Feature Branches: Imagine you're working on a feature branch that frequently needs to be merged into the main development branch. Each time you merge, you encounter the same merge conflicts. With git rerere, you only need to resolve these conflicts once. After that, Git remembers the resolutions and automatically applies them in future merges, saving you from resolving the same conflicts repeatedly.

Reapplying Patches or Fixes: Let's say you have a situation where you need to apply the same set of changes or fixes to multiple branches. When you encounter conflicts during this process, git rerere can remember how you resolved them the first time. Then, when you apply the changes to other branches, Git can automatically reuse the recorded resolutions, sparing you from manually resolving the same conflicts repeatedly.

Benefits of Git Rerere:

Git rerere offers several benefits that make it a valuable tool for developers, regardless of whether you prefer git merge or git rebase:

Time-saving: By reusing recorded resolutions, git rerere eliminates the need to manually resolve repetitive merge conflicts, saving you valuable time and effort.
Consistency: Git rerere ensures consistent conflict resolutions across multiple merges or rebases, reducing the chances of introducing errors or inconsistencies.
Improved productivity: With git rerere, you can focus on more critical tasks instead of getting stuck in repetitive conflict resolutions.

Conclusion:

Git rerere is a powerful feature that simplifies resolving repetitive merge conflicts. By enabling git rerere and recording conflict resolutions, you can save time, improve productivity, and ensure consistent conflict resolutions across your projects. Incorporate git rerere into your Git workflow, and say goodbye to the frustration of repetitive merge conflicts.

This Dot is a consultancy dedicated to guiding companies through their modernization and digital transformation journeys. Specializing in replatforming, modernizing, and launching new initiatives, we stand out by taking true ownership of your engineering projects.

We love helping teams with projects that have missed their deadlines or helping keep your strategic digital initiatives on course. Check out our case studies and our clients that trust us with their engineering.

About the author(s)

Mattia Magi

A Deep Dive into SvelteKit Routing with Our Starter.dev GitHub Showcase Example

Introduction SvelteKit is an excellent framework for building web applications of all sizes, with a beautiful development experience and flexible filesystem-based routing. At the heart of SvelteKit is a filesystem-based router. The routes of your app — i.e. the URL paths that users can access — are defined by the directories in your codebase. In this tutorial, we are going to discuss SvelteKit routing with an awesome SvelteKit GitHub showcase built by This Dot Labs. The showcase is built with the SvelteKit starter kit on starter.dev. We are going to tackle: - Filesystem-based router - +page.svelte - +page.server - +layout.svelte - +layout.server - +error.svelte - Advanced Routing - Rest Parameters - (group) layouts - Matching Below is the current routes folder. Prerequisites You will need a development environment running Node.js; this tutorial was tested on Node.js version 16.18.0, and npm version 8.19.2. Filesystem-based router The src/routes is the root route. You can change src/routes to a different directory by editing the project config. ` Each route directory contains one or more route files, which can be identified by their + prefix. +page.svelte A +page.svelte component defines a page of your app. By default, pages are rendered both on the server (SSR) for the initial request, and in the browser (CSR) for subsequent navigation. In the below example, we see how to render a simple login page component: ` +page.ts Often, a page will need to load some data before it can be rendered. For this, we add a +page.js (or +page.ts, if you're TypeScript-inclined) module that exports a load function. +page.server.ts If your load function can only run on the server— ie, if it needs to fetch data from a database or you need to access private environment variables like API key— then you can rename +page.js to +page.server.js, and change the PageLoad type to PageServerLoad. To pass top user repository data, and user’s gists to the client-rendered page, we do the following: ` The page.svelte gets access to the data by using the data variable which is of type PageServerData. ` +layout.svelte As there are elements that should be visible on every page, such as top-level navigation or a footer. Instead of repeating them in every +page.svelte, we can put them in layouts. The only requirement is that the component includes a for the page content. For example, let's add a nav bar: ` +layout.server.ts Just like +page.server.ts, your +layout.svelte component can get data from a load function in +layout.server.js, and change the type from PageServerLoad type to LayoutServerLoad. ` +error.svelte If an error occurs during load, SvelteKit will render a default error page. You can customize this error page on a per-route basis by adding an +error.svelte file. In the showcase, an error.svelte page has been added for authenticated view in case of an error. ` Advanced Routing Rest Parameters If the number of route segments is unknown, you can use spread operator syntax. This is done to implement Github’s file viewer. ` svelte-kit-scss.starter.dev/thisdot/starter.dev/blob/main/starters/svelte-kit-scss/README.md would result in the following parameters being available to the page: ` (group) layouts By default, the layout hierarchy mirrors the route hierarchy. In some cases, that might not be what you want. In the GitHub showcase, we would like an authenticated user to be able to have access to the navigation bar, error page, and user information. This is done by grouping all the relevant pages which an authenticated user can access. Grouping can also be used to tidy your file tree and ‘group’ similar pages together for easy navigation, and understanding of the project. Matching In the Github showcase, we needed to have a page to show issues and pull requests for a single repo. The route src/routes/(authenticated)/[username]/[repo]/[issues] would match /thisdot/starter.dev-github-showcases/issues or /thisdot/starter.dev-github-showcases/pull-requests but also /thisdot/starter.dev-github-showcases/anything and we don't want that. You can ensure that route parameters are well-formed by adding a matcher— which takes only issues or pull-requests, and returns true if it is valid– to your params directory. ` ` ...and augmenting your routes: ` If the pathname doesn't match, SvelteKit will try to match other routes (using the sort order specified below), before eventually returning a 404. Note: Matchers run both on the server and in the browser. Conclusion In this article, we learned about basic and advanced routing in SvelteKit by using the SvelteKit showcase example. We looked at how to work with SvelteKit's Filesystem-based router, rest parameters, and (group) layouts. If you want to learn more about SvelteKit, please check out the SvelteKit and SCSS starter kit and the SvelteKit and SCSS GitHub showcase. All the code for our showcase project is open source. If you want to collaborate with us or have suggestions, we're always welcome to new contributions. Thanks for reading! If you have any questions, or run into any trouble, feel free to reach out on Twitter....

Mar 22, 2023

5 mins

SvelteGit

Ensuring Accurate Workflow Status in GitHub for Enhanced Visibility

Introduction In the world of software development, GitHub workflows are crucial for automating CI/CD processes. However, a key challenge emerges when these workflows report a 'success' despite underlying issues, like failed tests. This is especially common in scenarios involving tests (e.g., Cypress) and notifications (e.g., Slack) within the same workflow. This blog post aims to highlight the importance of accurate GitHub workflow statuses for better visibility and team response, and how to ensure your workflows reflect the true outcome of their runs. The Problem with Misleading Workflow Statuses Consider a scenario in a GitHub workflow where end-to-end tests are run using Cypress. ` If these tests fail, but the workflow proceeds to a subsequent step, like sending a notification via Slack, which completes successfully, the entire workflow might still show a green checkmark. This misleading success status suggests everything is functioning as intended, when in fact, there could be significant underlying issues. The core issue is the determination of workflow success. Even if critical steps like testing fail, later steps without errors can override this, resulting in a false sense of security. This not only delays bug detection but can also lead to faulty code advancing in the CI/CD pipeline. It's crucial for the overall workflow status to accurately reflect failures in critical steps to ensure prompt and appropriate responses to issues. Crafting a Solution and Best Practices Ensuring Accurate Status Reporting To address the issue of misleading workflow statuses, it’s essential to configure your GitHub Actions properly. The goal is to ensure that the workflow accurately reflects the success or failure of critical tasks, such as running tests, regardless of the success of subsequent steps. Adjusting the Workflow Conditional Notifications: First, set up notifications to execute conditionally based on the outcome of critical steps. This ensures you're alerted of the workflow status without altering the overall result. For example, sending a Slack message if a Cypress test fails: ` Explicit Failure Handling: After configuring conditional notifications, explicitly handle failure scenarios. If a critical step like a Cypress test fails, force the workflow to exit with a failure status. This step is crucial to ensure that the overall workflow reflects the true status: ` Best Practices: Clear Step Separation: Clearly separate and label each step in your workflow for easier readability and troubleshooting. Regular Reviews: Periodically review your workflows to ensure they are aligned with the latest project requirements and best practices. Document Workflow Logic: Maintain documentation for your workflows, especially for complex ones, to aid in understanding and future modifications. By first setting up conditional notifications and then enforcing explicit failure handling, you maintain both alertness to issues and accuracy in workflow status. This approach ensures that failures in critical steps like tests are not overshadowed by subsequent successful steps, keeping the reported status of your workflow true to its actual state. Conclusion Accurate GitHub workflow statuses are vital for a transparent and efficient CI/CD process. By implementing conditional notifications and explicit failure handling, we ensure that our workflows truthfully represent the success or failure of critical tasks. This not only fosters better issue awareness and response but also upholds the integrity of our development practices. Embrace these steps as part of your commitment to maintaining clear and reliable automation processes in your projects. Happy coding!...

Mar 22, 2024

3 mins

GitHubGit

"How do I undo my most recent commit?" - Mastering the git reset command

"How do I undo my most recent commit?" - Mastering the git reset command Git is a powerful version control system, but even experienced developers sometimes make mistakes. Whether you've committed changes to the wrong branch, made a typo in your commit message, or simply want to undo recent changes, the git reset command is your go-to solution. In this post, we'll explore how to use git reset to manage your commit history effectively. The Basics of git reset At its core, git reset moves the HEAD and current branch pointer to a specified commit, effectively "resetting" your working directory to a previous state. The basic syntax is: ` Where specifies how to handle changes in the working directory and staging area, and is the commit you want to reset to. Soft vs. Hard Reset: Understanding the Difference Git reset has two main modes: --soft and --hard. Let's explore each: Soft Reset (--soft) A soft reset moves your HEAD to the specified commit but keeps your changes staged. This is useful when you want to undo commits but keep the changes for recommitting. Example: ` This command undoes the last commit, keeping the changes staged. You can now make additional changes or recommit with a new message. Hard Reset (--hard) A hard reset is more drastic. It moves your HEAD to the specified commit and discards all changes after that commit. Example: ` This command undoes the last commit and discards all changes. Be cautious with this command, as it can lead to data loss! Specifying a Commit Hash Instead of using relative references like HEAD~1, you can specify an exact commit hash: ` This resets to the commit with hash 1a2b3c4, keeping changes staged. Using HEAD~n Notation The HEAD~n notation allows you to specify how many commits back you want to reset. For example: ` This resets to three commits before the current HEAD, discarding all changes. Reverting Pushed Changes If you've already pushed commits you want to undo, you should use git revert instead of git reset to avoid rewriting public history. However, if you must use git reset on a shared branch, you'll need to force push: ` Be extremely cautious with force pushing, as it can cause issues for other developers. Generic Usage of git reset git reset can also be used to unstage changes: ` This removes file.txt from the staging area without changing its contents. Conclusion The git reset command is a powerful tool for managing your Git history. Whether you're undoing recent commits, unstaging changes, or completely resetting your working directory, understanding the different modes of git reset can help you navigate tricky situations in your Git workflow. Remember to use git reset with caution, especially when working with shared repositories. When in doubt, create a backup branch before performing any reset operations....

Oct 18, 2024

2 mins

Git

Svelte 5 is Here!

Svelte 5 was finally released after a long time in development. Fortunately, we've been able to test it for some time, and now it has a stable release. Let's dig into its features and why this is such a significant change, even though Svelte 4 code is almost 100% compatible. Svelte syntax everywhere This is one of my favorite additions. Previously, Svelte syntax was limited to a component element. Refactoring code from a component and moving it to a JavaScript file worked differently. Now you can use the .svelte.js or .svelte.ts extension, which allows you to use the same syntax everywhere. It's important to note that it's a way to express that this is not just JS, and what you write may be compiled to something else, just like .svelte files are not just html even though they look very similar. Runes The introduction of runes is one of the most significant changes in Svelte. Many users felt attracted to variables being instantly reactive in previous versions. ` There was, however, a lot of magic underneath and a considerable amount of work from the compiler to make it behave reactively. $state In Svelte 5, a reactive variable has to be explicitly declared using the $state rune, which brings a clear distinction between what is reactive and what isn’t. ` In the previous code, $state is not an actual function being called; it's a hint for the compiler to do something special with this declaration. Rune names always start with a dollar sign ($) and do not need to be imported. However, there’s much more to the changes than just the way we declare reactive variables. Runes bring a lot of new features that make Svelte 5 a great improvement. In Svelte 5, objects or arrays use Proxies to allow for granular reactivity, meaning that individual properties in an object are reactive, even if they are nested objects or arrays. If you modify a property, it will only update that property and will not trigger an update on the whole object. It also supports triggering updates when methods like array.push are called. In previous versions, an assignment was required to trigger an update: ` To have a similar behavior of svelte 4 (no deep reactivity), use the $state.raw() rune. This syntax of .* is common for related features of a rune: $state.raw() will require an assignment to trigger reactivity. ` Because proxies are used, you may need to extract the underlying state instead of the proxy itself. In that case, $state.snapshot() should be used: ` $derived We will use $derived and $derived.by to declare a derived state. The two runes are essentially the same, except one allows us to use a function instead of an expression, allowing for more complex operations to calculate the derived values. ` $effect Effects are useful for running something triggered by a change in state. One of the things you'll note from the $effect rune is that dependencies don't need to be explicit. Those will be picked from reactive values read synchronously in the body of the effect function. ` Something to bear in mind is that these dependencies are picked each time the effect runs. The values read during the last run become the dependencies of the effect. ` Depending on the result of the random method, foo or bar will stop being a dependency of the effect. You should place them outside the condition so they can trigger reruns of the effect. *Variants* of the effect rune are $effect.pre, which runs before a DOM update, and $effect.tracking(), which checks for the context of the effect (true for an effect inside an effect or in the template). $props This rune replaces the export let keywords used in previous versions to define a component's props. To use the $props syntax, we can consider it to return an object with all the properties a component receives. We can use JavaScript syntax to destructure it or use the rest property if we want to retrieve every property not explicitly destructured.. ` $bindable If you want to mutate a prop so that the change flows back to the parent, you can use the $bindable prop to make it work in both directions. A parent component can pass a value to a child component, and the child component is able to modify it, returning the data back to the parent component. ` $inspect The $inspect rune only works in dev mode and will track dependencies deeply. By default, it will call console.log with the provided argument whenever it detects a change. To change the underlying function, use $inspect.with().with): ` $host The host rune gives access to the host element when compiling as a custom element: ` ` Other changes Another important change is that component events are just props in Svelte 5, so you can destructure them using the $props() rune: ` A special children property can be used to project content into a component instead of using slots. Inside the components, use the [@render[(https://svelte.dev/docs/svelte/@render) tag to place them. ` Optional chaining (?.) prevents from attempting to render it if no children are passed in. If you need to render different components in different places (named slots before Svelte 5, you can pass them as any other prop, and use @render with them. Snippets Snippets allow us to declare markup slices and render them conveniently using the render tag (@render). They can take any number of arguments. ` Snippets can also be passed as props to other components. ` ` Conclusion Some exciting changes to the Svelte syntax were introduced while, at the same time, maximum compatibility efforts were made. This was a massive rewrite with numerous improvements in terms of performance, bundle size, and DX. Besides that, a new CLI has been released, making the whole experience of starting a project or adding features delightful. If you haven't tried Svelte before, it's a great time to try it now....

Nov 27, 2024

4 mins

Svelte

Let's innovate together!

We're ready to be your trusted technical partners in your digital innovation journey.

Whether it's modernization or custom software solutions, our team of experts can guide you through best practices and how to build scalable, performant software that lasts.

Mastering Git Rerere: Solving Repetitive Merge Conflicts with Ease

Mastering Git Rerere: Solving Repetitive Merge Conflicts with Ease

Introduction:

Understanding Git Rerere:

Configuring Git Rerere:

How to use it:

Benefits of Git Rerere:

Conclusion:

Mattia Magi

You might also like

A Deep Dive into SvelteKit Routing with Our Starter.dev GitHub Showcase Example

Ensuring Accurate Workflow Status in GitHub for Enhanced Visibility

"How do I undo my most recent commit?" - Mastering the git reset command

Svelte 5 is Here!

Let's innovate together!

You might also like

A Deep Dive into SvelteKit Routing with Our Starter.dev GitHub Showcase Example

Ensuring Accurate Workflow Status in GitHub for Enhanced Visibility

"How do I undo my most recent commit?" - Mastering the git reset command

Svelte 5 is Here!