Why does git prevent merging binary files?

@thelma.stanton 

Git does not prevent merging binary files outright, but it does not handle binary file merging as effectively as it does for plain text files. The reason behind this lies in the fundamental design principles of Git.

Git is primarily designed for tracking changes in source code, which is typically plain text. Git uses an algorithm called three-way merge (also known as a "merge commit") to automatically merge changes from different branches into one unified version. This algorithm relies on comparing and merging line-by-line changes in text files, which works well for source code.

Binary files, on the other hand, are not easily comparable or mergeable because they lack a clear line-based structure. These files, such as images, audio files, compiled binaries, etc., are stored as a sequence of bytes without any higher-level structure. When Git encounters a binary file during a merge, it treats it as an opaque blob of data rather than trying to understand the contents and merge them intelligently.

As a result, Git's default behavior for binary files is to keep only one version of the file, discarding the changes from other branches during a merge conflict. This behavior is generally desired for binary files, as merging their contents automatically could lead to unexpected results or data corruption, especially when the binary file formats are complex.

To handle binary files more effectively, Git provides a feature called "binary file merge" or "binary merge driver." With a custom merge driver, users can define how to merge specific types of binary files by writing a script or specifying a specific tool to use during the merge process. However, this approach requires manual intervention and configuration, as the appropriate tools and merge strategies need to be determined for each specific binary file type.

Overall, Git's focus on managing text-based source code and its inability to visually analyze or understand binary file contents lead to the caution and limitations around merging binary files.

@thelma.stanton 

In a nutshell, Git prevents merging binary files seamlessly because binary files lack a line-by-line structure that Git uses for merging text files. Merging binary files could potentially lead to data corruption or unexpected results due to their complex and opaque nature. Git's design primarily caters to tracking changes in text-based source code efficiently rather than handling binary file merges. While Git does not prevent merging binary files entirely, it is not as effective in this context compared to its handling of plain text files. Developers typically use custom merge drivers or manual intervention to handle binary file merges in Git.