What exactly does each line in the graph represent?

Question

I work with a team of developers developing enterprise applications, and we have used source tree with Git for about half a year now. However, we still can't seem to figure out exactly what each line in the graph represents? Is each line one branch? If so, which color corresponds to which branch? Why is there no key?

Seth · Accepted Answer

In general, each line is one branch. Keep in mind that working in a team environment will often create multiple branches with the same name (in the graph). For example, my repository's "master" is a different branch than my coworker's "master". As long as we are staying in sync, these will be displayed together, but if the two of us make commits simultaneously, someone has to merge, and the "master" branch will temporarily diverge to reflect that activity (unless the merger uses rebase, which rewrites their history to make it appear as if the branch did not diverge).

Colors are arbitrary, intended only as a visual aid when scrolling through the history. It seems that Sourcetree cycles through a fixed sequence of colors, starting with blue for the most recently touched branch.

I believe the reason this gets so confusing is because the distributed nature of Git makes a commits membership in any particular branch much more ambiguous that for a centralized system like SVN.