How to Use GitHub Copilot with Python

Git is a distributed version control system developed by Linus Torvalds. It has become the standard in software development due to its efficiency and flexibility. During the development process, there are situations when you need to urgently switch to another branch using the checkout command and make changes related to a different task. However, the current changes may not be ready for a commit yet, and you don’t want to lose them. In such situations, the git stash command comes to the rescue. This tool is indispensable, allowing you to safely store current changes for a while and then return to them without disrupting the integrity of the repository. Let’s explore how to use git stash in development. Basics of git stash Let's think about how we normally work with the codebase and Git. We create something (a function or a small module), then run git add, followed by git commit and git push. Great; we have finished the task and can move on to the next one. But what if the context changes, and you need to switch urgently? You may not have finished writing the module yet, but you must complete another task now. You don’t want to leave the commit unfinished. This is where git stash comes in. So, what does it do? The process of saving temporary changes consists of two stages: stash: We save the changes to a special storage. You can also add a comment for them. pop or apply: We bring the changes back into our working directory. Preparation The version control system must track changes you are going to stash. You can add files to the tracked list using the command: git add . Creating a Stash To create a stash, use the following command: git stash Output: Saved working directory and index state WIP on master: 099797d start By default, the stash name contains the abbreviation “WIP” (Work In Progress) and the branch name. If you want to specify a comment, you can use the following commands: git stash push or git stash save: git stash push -m "<your comment>" The result will be: Saved working directory and index state On master: <your comment> The same result will occur with this command: git stash save "<your comment>" However, this command is considered deprecated — you can check the documentation for more details. Retrieving Changes Now, let’s return to the original task. We need to bring back the hidden changes. Use the command: git stash pop The output will tell you that the changes have been applied to the current working area and can now be used. It will also indicate that all data has been removed from the special temporary storage. If you need to apply the changes without removing them from the stash, use the command: git stash apply Additional Commands and Parameters List All Stashes To view the list of changes that have been stashed in the repository, you can use the command: git stash list Example output: stash@{0}: On master: User Story #2010stash@{1}: WIP on master: 099797d start Applying Specific Changes by Index To apply a specific change, you can use the pop command with the stash index: git stash pop 'stash@{1}' Example output: no changes added to commit (use "git add" and/or "git commit -a")Dropped stash@{1} (563f9c20ab12525795911fbed0c4ebf4a1298b4e) Additional Parameters for the git stash Command If you need to stash changes while keeping them in the working directory, use the --keep-index flag. In this case, files added to the tracked list using the git add command will remain: git stash --keep-index Output: Saved working directory and index state WIP on master: 099797d start If you call git status after this, the modified files will still be there: On branch main Changes to be committed: (use "git restore --staged <file>..." to unstage) modified: GitStash/Program.cs modified: GitStash/SomeModule.cs If you need to add files that git does not track yet, use the --include-untracked flag: git stash --include-untracked When you retrieve changes using pop, you will see a message about the presence of untracked files: ... Untracked files: (use "git add <file>..." to include in what will be committed) GitStash/NewClass.cs ... Sometimes it may be convenient to split the uncommitted changes into separate stashes. In this case, the git stash -p command will help: git stash -p For each change, hiding will be done separately, with a prompt for confirmation. Here are the options for confirmation: ? — to show all options y — to stash the change n — to not stash this part of the change q — to stash all selected parts and finish Viewing Specific Changes in a Stash The show command displays information about the changes in a specific stash, for example: git stash show GitStash/Program.cs    | 3 ++- GitStash/SomeModule.cs | 7 +++++- 2 files changed, 8 insertions(+), 2 deletions(-) You can also specify the index of a specific stash: git stash show 'stash@{1}' Example output: GitStash/SomeModule.cs | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) Clearing Changes from a Stash To remove a specific stash, you can use the drop command. If you don't specify an index, it will remove the most recent set of stashed changes: git stash drop Or: git stash drop 'stash@{1}' Output: Dropped stash@{1} (bedb3c2add59a3f203e2367602328dca8b33b6e9) To completely clear the stash storage, you can use the command: git stash clear Creating a New Branch from a Stash To create a new branch based on stashed changes, use the following command: git stash branch <branch name> <stash index> Or simply: git stash branch <branch name> For example: git stash branch some-feature stash@{2} How It Works The set of changes we hide in the stash is actually a series of commits. Running this command creates two or three commits: The commit stash@{0} contains the stashed files. The parent commit is the HEAD commit in Git's current working directory. If we run the command with the --keep-untracked flag, a separate commit will be created for the untracked files. What happens when you run the pop command? The stashed changes are returned to the repository's working copy and indexed by Git. Other stashes are shifted. The extracted commits are deleted. The .git/refs/stash file contains a reference to the last commit for the stash. cat .\.git\refs\stash Output: 07ea0c456356e883610f43c20d9cb298ff2ebb8a Use Cases Let's look at some common use cases for this mechanism in practice: Backup Before Merge or Rebase The merge / rebase commands are necessary when working with multiple branches. However, conflicts often arise that can cause important changes in the current working directory to be lost. Before performing a merge, ensure that the current branch is up to date, i.e., it doesn't contain unsaved changes. If you have unsaved changes that should be preserved before merging, run this command: git stash push -m "Backup before branch merge" Proceed with the merge, running merge or rebase. Conflicts may arise between the changes in the current branch and the changes in the other branch when executing these commands. You can resolve conflicts using either IDE tools or Git. After successfully completing the merge or rebase, you can restore the changes to the current working directory using apply or pop. Non-Debugging Changes The stash mechanism can also be helpful for working with non-debugging changes, such as temporary fixes, comments, or code formatting. Instead of committing these changes to the current commit, you can use git stash to save them temporarily. This helps in creating clean commits and improves the structure of the Git history. Effective Project Configuration Management Another scenario for using git stash is effectively managing project configurations. Depending on the task or environment you are working in, you might need to modify configuration files, but permanently saving them might not be practical. Saving different configurations Suppose there is a configuration file that defines the parameters for your application (e.g., config.json). You need several versions of this file for different use cases (e.g., local development, testing, and production). You can use the stash to save these configurations. # Saving the configuration for local development git stash save "Local configuration" # Saving the configuration for testing git stash save "Testing configuration" # Saving the configuration for the production environment git stash save "Production configuration" Applying configurations as needed When you need to switch between different configurations, simply use git stash apply or git stash pop to apply the corresponding stash: # Applying the configuration for testinggit stash apply stash@{1} Tips for Effective Using git stash Use clear stash descriptions. The default messages created for stashes usually don’t convey the essence of the changes — they’re simply an abbreviation like WIP, a commit ID, and the branch name: WIP on master: 099797d start Use the push or save commands to add descriptive messages, for example: git stash save "test configuration" Or: git stash push -m "Started working on issue #11 - added contract for the module" Check and clean your stashes. During long-term project development, you may accumulate a large number of changes that are no longer relevant. Use the list and show commands to view the changes and git stash drop to remove obsolete stashes. This mechanism is not intended for long-term data or change storage. Use stash with other commands. You can combine git stash with other commands, such as git stash branch, to create new branches, or with the rebase and merge commands to back up local changes. Conclusion In this article, we’ve explored the git stash command and its use cases. git stash is a powerful tool that can significantly simplify managing changes in your repository and improve your workflow. We’ve examined both basic and advanced scenarios for using this tool, including creating, applying, extracting, and managing stash entries.

In most cases, working with the Git version control system is done locally. However, you sometimes need to sync with a remote repository to update your local storage. Git provides two key commands for this: git fetch and git pull. A remote repository is a storage location hosted on the network, usually on platforms like GitHub, GitLab, or Bitbucket. These services allow developers to collaborate on projects, make changes, and synchronize code between local and remote versions. Both commands are used to download updates from a remote repository, but they work differently. In this guide, we will explore their practical applications and highlight their key differences. Prerequisites Since this article covers practical usage, you’ll need the following: A server, virtual machine, or computer with any operating system where Git can be installed. A Git client pre-installed. An account on GitHub. The git fetch Command Let’s start with what git fetch does. git fetch is used to grab the latest data from a remote repository and put it into your local storage without modifying any files in your working directory. Instead, it updates the so-called remote-tracking branches, which reflect the state of the remote repository at the time the command is executed. This is how git fetch works: Establishes a connection with the remote repository. Downloads new commits, files, branches, and tags. The data is added to the local repository but not merged with the current working branch. Basic syntax of git fetch: git fetch <remote-repository-url> Useful options: git fetch --all — Downloads updates from all remote repositories linked to the local storage. git fetch --dry-run — Checks for changes before downloading without making any actual changes. git fetch --force — Forcefully updates data in the local repository, overwriting any conflicts. git fetch --tags — Downloads all tags from the remote repository. git fetch --prune — Removes references to branches that were deleted in the remote repository. The git pull Command Unlike git fetch, the git pull command downloads the latest changes from a remote repository and automatically merges them into your current local branch. Essentially, executing git pull involves two operations: git fetch — Downloads new data. git merge — Merges the downloaded changes with the local branch. This is how git pull works: Establishes a connection with the remote repository. Downloads the latest data, including commits, files, tags, and branches. The downloaded changes are merged into the current local branch. Basic syntax of git pull: git pull Useful options: git pull [remote-repository] [branch] — Downloads changes only from the specified repository and branch. For example, git pull origin main updates the local main branch from the remote repository origin. git pull --rebase — Instead of performing a standard merge, this applies the changes on top of the local commits, helping to avoid unnecessary merge commits. Comparison: git fetch vs git pull To better understand the differences between these two commands, here's a comparison table: Criterion git fetch git pull Action Only downloads changes Downloads and merges changes Impact on Local Repository Does not modify files or branches Modifies the current branch and files Safety Safe, as it does not cause conflicts May cause conflicts during merging Previewing Changes Allows reviewing and analyzing changes before merging Automatically integrates changes without preview Flexibility Requires manual merging Merges automatically When to Use Git Fetch vs. Git Pull When to Use git fetch Before Making Changes to the Source Code: git fetch allows you to see which commits have been made on the remote branch and evaluate the changes before merging them into your local branch. When Working in a Team: If multiple developers are working on the project, git fetch helps you stay up-to-date with their work and minimize potential conflicts before integrating changes. To Retrieve New Branches and Tags: If a new branch or tag has been added to the remote repository, git fetch will download them without automatically switching to them. When to Use git pull To Get the Latest Changes: In team projects, members regularly make updates. To bring all the latest changes into your local repository, use git pull. For Quick Branch Updates: If you need to quickly update your branch without analyzing the changes beforehand, using git pull is the easiest approach. Using Git Fetch and Git Pull in Practice Creating a Repository on GitHub Log in to GitHub. If you don’t have an account, you can register a new one. Click on the New button to create a new repository. Provide a name for the repository and select the Public option. Click on your profile picture in the upper-right corner and select Settings from the drop-down menu. Scroll down to Developer settings on the left. Expand Personal access tokens and go to Tokens (classic). Click on Generate new token, then Generate new token (classic). If prompted, authenticate using the mobile app. Give the token a name and set an expiration date. Under permissions, select the repo category. Click on Generate token to create the token. Copy and save the token, as it won’t be shown again. Creating a Local Repository Go to the server where Git is installed. Create a new directory to store your files and navigate to it: mkdir test-git-fetch-pull && cd test-git-fetch-pull Initialize a new Git repository: git init Create a new file and add a line to it: echo "Test git fetch and pull commands!" > newfile1.txt Add the file to the staging area: git add newfile1.txt Create an initial commit: git commit -m "Initial commit" If you see the message: Author identity unknown*** Please tell me who you are You need to set your name and email using: git config --global user.email "example@example.com"git config --global user.name "<name>" Then, repeat the commit command: git commit -m "Initial commit" Add the remote repository. Use the command from the main page of your newly created repository on GitHub. For example: git remote add origin https://github.com/<github-account>/test-git-fetch-pull.git Push changes to the remote repository: git push -u origin main When prompted for Username for 'https://github.com', enter your GitHub username. When prompted for Password for 'https://<username>@github.com', enter the previously generated token. Go back to the GitHub web interface and check that the file is present in the repository. Working with Changes Now, let’s simulate changes in the remote repository. Open the file for editing directly in the GitHub interface. Add a new line at the end of the file. Click the Commit changes button on the right. Go back to the server where your local repository is located and run: git fetch origin Now, check the file content: cat newfile1.txt You'll notice that git fetch downloaded the changes from the remote repository, but the local branch (main) and the file remained unchanged. However, the changes can be seen in the remote branch: git log origin/main To see exactly what changes were made in the remote repository after running git fetch, use: git diff main origin/main Now, let's pull the changes into the local branch: git pull origin main Display the file content again: cat newfile1.txt Now, the changes made in the GitHub interface are applied to the local copy of the repository. Resolving Conflicts When Using git pull When using git pull, you may encounter conflicts. In Git terminology, a conflict occurs when the system cannot automatically merge changes from two different sources — the local and remote repositories. To learn how to resolve conflicts, let's go through a practical example. We'll simulate the following situation: We have a repository containing a file named future-file1.txt. Two developers (Developer 1 and Developer 2) are working on the same branch (main). Preparing the Repository Create a new repository in GitHub. Follow the same steps as in the previous chapter to create a new repository. On the server, create a new directory and navigate to it: mkdir git-conflicts && cd git-conflicts Initialize the Git repository: git init Create a new file: touch future-file1.txt Write the first line into the file: echo "First message" > future-file1.txt Stage the file: git add future-file1.txt Commit the changes: git commit -m "Initial commit" Connect the local repository to GitHub. Replace the URL with the one for your GitHub repository: git remote add origin https://github.com/<github-account>/git-conflicts.git Push changes to the remote repository: git push -u origin main You'll be prompted to enter your GitHub username and personal access token. Making Changes as Developer 2 Now, let's simulate the scenario from the perspective of the second developer (Developer 2). On another machine or in a new directory on the same server, run: git clone https://github.com/<github-account>/git-conflicts.git At this point, both developers have an up-to-date copy of the repository. Making Changes as Developer 1 Switch back to the local repository used by Developer 1: Add a new line by overwriting the content of future-file1.txt: echo "Second message" > future-file1.txt Stage the changes: git add future-file1.txt Commit the changes: git commit -m "Second commit" Push changes to the remote repository: git push origin main Conflict At this point, Developer 1's changes are in the remote repository. However, Developer 2 still has the old version of future-file1.txt. Navigate to the project folder that was previously cloned by Developer 2. Overwrite the file by adding a new message: echo "Third message" > future-file1.txt Stage the file: git add future-file1.txt Commit the changes: git commit -m "Third commit" Pull the latest changes from the remote repository: git pull origin main As you can see, Git has detected a conflict: When viewing the file, you will notice a conflict block in the file, marking the conflicting changes. Resolving the Conflict To resolve the conflict, you need to delete the lines starting with <<<<<<< and ending with >>>>>>>. Then, you can decide whether to keep only the local changes or to retain the old ones and add the new ones. As an example, let's keep the changes from both developers: Developer 1's message ("Second message") Developer 2's message ("Third message") After editing the file, stage it again: git add future-file1.txt Commit the resolved conflict: git commit -m "Resolved conflict" Push the changes to the remote repository: git push origin main You will need to enter your username and token to push the changes. Go to the GitHub interface and verify the result. Conclusion The git fetch and git pull commands are used to retrieve the latest changes from a remote repository into your local repository, but they do so differently. git fetch allows you to safely fetch updates and analyze the changes made by others without affecting your current working copy. This is especially useful for avoiding unexpected conflicts, as no changes are applied automatically. git pull fetches the data and immediately merges it into the local repository. This process requires caution. If conflicts occur, you will need to resolve them manually. The choice between these commands depends on your goals: If you want to check changes first, use git fetch. If you need to quickly update the code, use git pull, but be aware of the possible conflicts.

In Git, managing code history is important for tracking changes. For this purpose, git supports several commands, such as commit, log, diff, branch, merge, revert, and rebase. The git rebase command, in particular, is useful for keeping branch histories clean by allowing developers to reapply commits from one branch to another. In this article, we’ll discuss what git rebase is, how it differs from the git merge command, and how to use it to maintain a structured, linear commit history that’s easier to read and review. Understanding Git Rebase: What Is It? The git rebase command allows us to move, combine, reorder, edit, or remove commits. Moreover, it simplifies the project history by moving the commits of one branch onto the base of another branch. Rebase in git is especially useful when integrating changes into a feature branch, resulting in a streamlined history without unnecessary merge commits. Git Rebase vs. Git Merge: What’s the Difference? Both merge and rebase commands are used to combine branches, but they differ in how the commit history looks after one branch is added to another. Here’s a comparison to understand when to use rebase versus merge: Git Merge: It combines the histories of both branches and creates a merge commit, marking the point where they joined. This commit retains the complete history of both branches. Git Rebase: It applies changes from one branch to another and rewrites the history as though all work was done linearly. Git Merge maintains separate histories for each branch, while Git Rebase linearizes the history, making it appear as if all work was done in a straight line. When using git merge, the focus is on merging feature branches, whereas git rebase is used to rewrite and clean up the commit history for better organization and readability. Basic Syntax and Options for Git Rebase The git rebase command allows users to transfer commits from the current branch to the base of another branch. The basic syntax of the git rebase command is shown below: git rebase <target-branch> Users can use different options with the git rebase command, which are listed below:  git rebase master: This command adds all the changes from the master branch to your current branch. -I or --interactive: This option opens an editor to reorder, combine, or modify commits interactively. --onto <newbase>: This option enables us to set a new base commit for the rebase. We can use it to move several commits to a different branch or commit. --skip: This option skips a commit if there's a conflict during rebase. It tells Git to ignore that commit and continue with the rebase. --no-verify: This option ignores any pre-commit checks set up in the repository. It’s useful if we want to commit quickly without running those checks. --auto-squash: It automatically applies the fixup or squash flags to commits. This is helpful for cleaning up commit history during an interactive rebase. These git rebase options should be used carefully, as they can change the commit history of the repository. It is recommended to back up your code before running the rebase command in Git. This way, users can restore the original code if anything goes wrong. How to Perform an Interactive Rebase Interactive rebasing enables users to reorder, combine, or edit commit messages. This practice gives users precise control over their history. Go through the following steps to perform an interactive rebase: Step 1: Switch to the feature branch Users can use the git checkout command to navigate to a different branch in a Git repository: git checkout <feature-branch> This command changes the user's current working branch to the specified <feature-branch>. After switching, any subsequent Git operations, including rebase, will be performed in the context of that branch. Step 2: Start interactive rebase Users can run the rebase command with the -i option to perform an interactive rebase: git rebase -i <target-branch> When a user runs this command, it opens the default text editor. The user will see a list of commits from the current branch that are not present in <target-branch>. Each commit comes with actions to choose from, such as: pick: Keep the commit as it is. edit: Stop and allow changes to the commit (like the message or the files). squash: Combine this commit with the one before it. drop: Removes a commit.  After the user makes the desired changes and saves the file, Git will continue the rebase based on the selected choices. Handling Merge Conflicts During Rebase When rebasing, conflicts can occur if the same line of code is modified in both branches. In that case, Git pauses the rebase process, allowing users to resolve conflicts. Follow the steps below to resolve the merge conflicts during the rebase: Step 1: Identify Conflicting Files Run the git status command to see where the problem/conflict lies in a Git repository: git status This command displays a list of files that have conflicts, marked as unmerged. Step 2: Edit the Conflicted Files When there are conflicts during a Git operation, like a merge or rebase, Git marks the conflicting parts in the files with special markers: <<<<<<< HEAD: It shows the user's changes (from the current branch). =======: It separates the user's changes from the other branch's changes. >>>>>>> <branch-name>: It shows the end of the conflicting section and shows the name of the branch with the conflicting changes. To resolve the conflicts, users should open the files in a text editor and decide which changes to keep. They can choose to: Keep their changes. Keep the changes from the other branch. Combine both sets of changes. After making the edits, it's important to remove the conflict markers to clean up the code and make sure it works properly. Step 3: Stage the Resolved Files Once conflicts have been resolved, the next step is to stage the resolved files. This is done using the following command: git add <file-name> Replace <file-name> with the file’s name that was edited. If multiple files are resolved, they can be added simultaneously or individually. Step 4: Continue the Rebase After staging the resolved files, users can continue the rebase process with the command: git rebase --continue How to Abort, Skip, or Continue a Rebase Users can manage the rebase process by executing the git rebase command with the abort, skip, and continue options. Aborting the Rebase Run the git rebase command with the --abort option to cancel the ongoing rebase and return the branch to its original state: git rebase --abort Skipping the Rebase Similarly, if a user runs into unresolved conflicts during a rebase, he can execute the git rebase command with the --skip option to omit the problematic commit: git rebase --skip Continuing the Rebase If we encounter conflicts while rebasing, we need to resolve them first. After fixing the issues, we can run the rebase command with the --continue option to continue the rebasing process: git rebase --continue Common Mistakes Users can encounter several issues during Git rebase, such as merge conflicts, uncommitted changes, aborted rebase attempts, etc. Here are some common mistakes that users may face while rebasing: Merge Conflicts Users can face merging conflicts when changes in the rebased branch overlap with the base branch. These conflicts require manual resolution. Use the git add <filename> command to mark conflicts as resolved. Then, continue with the git rebase --continue command. Uncommitted Changes If you have uncommitted changes in your working directory, Git won't allow a rebase. In that case, commit or stash your changes with git stash before starting the rebase. Rebasing Shared Branches Rebasing the shared branches can create confusion and conflicts. To avoid this issue, users can rebase the branches that they own or are not currently used by anyone else. Complex History A branch with a complicated commit history can make the rebase process error-prone. In such cases, consider using git merge instead or simplify the history before rebasing. Incorrect Rebase Sequence Specifying the wrong base commit can lead to unexpected changes. Therefore, it is recommended to always double-check that you are rebasing onto the correct branch. Apart from this, the git rebase command has several disadvantages, including increased complexity compared to merging, especially with complex commit histories. It can lead to lost commits if the wrong branch is rebased or if conflicts are unresolved. Additionally, rebasing alters the commit history in public repositories, which makes collaboration difficult. Conclusion In Git, the rebase command helps maintain a clean and readable commit history. However, it requires careful usage due to certain challenges. Therefore, before making significant changes to a branch’s commit history, it’s important to carefully consider the risks and benefits of using the git rebase command.