How to use the command "git range-diff" (with examples)

Git is a widely-used distributed version control system that allows multiple developers to collaborate on a project by tracking changes and managing source code. The “git range-diff” command is a powerful tool that helps compare two commit ranges, making it easier to understand the changes introduced by different sets of commits. This article will illustrate three use cases of the command and provide code examples, motivations, explanations, and example outputs for each.

Use case 1: Diff the changes of two individual commits

Code:

git range-diff commit_1^! commit_2^!

Motivation: In a collaborative development environment, it’s important to review and understand the changes introduced by individual commits before merging them into a shared branch. By using “git range-diff” with two individual commit references, you can easily see the differences between them.

Explanation: In this use case, the command takes two individual commits: “commit_1” and “commit_2”. The “^!” suffix is used to exclude merge commits and only consider the changes introduced by those individual commits.

Example output:

commit_1

    + This line was added

- This line was removed

commit_2

+ Another line was added

Use case 2: Diff the changes of ours and theirs from their common ancestor

Code:

git range-diff theirs...ours

Motivation: During an interactive rebase or when merging branches, it can be useful to compare the changes introduced by “ours” (current branch) and “theirs” (other branch) from their common ancestor. This helps identify conflicting changes and ensures proper resolution.

Explanation: In this use case, the command uses the “theirs…ours” range to compare the changes. The “theirs” represents the branch you want to compare against, and “ours” represents the current branch. The command automatically detects the common ancestor and performs a diff on the changes.

Example output:

common_ancestor...theirs

- This line was removed

common_ancestor...ours

+ This line was added

Use case 3: Diff the changes of two commit ranges

Code:

git range-diff base1..rev1 base2..rev2

Motivation: When rebasing commits from one base to another, it’s crucial to ensure that conflicts have been resolved appropriately. By using “git range-diff” with two commit ranges, you can easily spot any unresolved conflicts and review the changes between the two ranges.

Explanation: This use case involves providing two commit ranges separated by “..”. The first commit range, “base1..rev1”, represents the original range of commits. The second commit range, “base2..rev2”, represents the rebased range. The command then compares the changes between the ranges.

Example output:

base1...base2

- This line was removed

base1...rev1

  Modified line 1

+ This line was added

base2...rev2

  Modified line 1

Conclusion:

The “git range-diff” command is a versatile tool for comparing commit ranges in Git. By understanding its various use cases and providing relevant commit references, you can utilize this command to efficiently analyze changes and ensure the integrity of your codebase. Whether you want to review individual commits, compare branches, or validate conflict resolutions, “git range-diff” has you covered.