Side-by-side code diff view UX

I'm working on code diff view design, and would like to gather your opinion on two existing patterns.

Below are screenshots of two different side-by-side diff view designs.

One is leaving white space for code that didn't exit in the old version (on the left), and the line numbers don't continue.

The other design is similar to sankey diagram where the white spaces are removed on the left side, you can see lines of code in its original flow.

Which design do you prefer and why?