1. nbdime: Notebook Diffing and Merging
Vidar Tonaas Fauske
Martin Sandve Alnæs
Min Ragan-Kelley
Simula Research Laboratory, Oslo, Norway

2. Outline Notebook format: Why we need custom diff/merge
Interfacing nbdime with git
Merge tool

3. Why do we need custom diff/merge?
Notebook format:
Sequences
Dictionaries
(Strings = sequences)
Atomic values: numbers, booleans, binary data (base64)

4. Why do we need custom diff/merge?
Standard algorithms: - Sequence of strings (lines) We have a lot of a priori information!

5. How to interface CLI applications Rich renderes
git diff driver / difftool
git merge driver / mergetool
Rich renderes

6. Diffing entries
App / driver / CLI difftool
Difftool: Browser view

7. Merging notebooks Major unit: Cell
Source is more important than outputs!
Source is “traditional” string merge
Outputs are atomic (pick and mix)

8. git mergedriver Associate ipynb files with our merger
Fewer conflict than default merger
A: Execution count changed, B: Cell deleted

9. Mergetool – git mergetool

10. Mergetool – Outputs mockup

11. Summary Custom diff/merge because of structured format (JSON)
Also allows us to make informed merges
Interfacing nicely with git
Rich rendering allows for better oversight

12. Thanks!