Git Rev News: Edition 48 (February 27th, 2019)

Welcome to the 48th edition of Git Rev News, a digest of all things Git. For our goals, the archives, the way we work, and how to contribute or to subscribe, see the Git Rev News page on

This edition covers what happened during the month of January 2019. It also covers the Git Contributor Summit and the Git Merge conference that took place on January 31th and February 1st.




Last November Derrick Stolee, who prefers to be called just Stolee, sent a patch series to the mailing list to speed up git push operations by implementing and using a new “sparse” tree walk algorithm.

Stefan Beller wondered how users can know about this new algorithm and if it should be turned on by default for users. Stolee replied that indeed “we should actually make the config setting true by default, and recommend that servers opt-out”.

Junio Hamano, the Git maintainer, disagreed saying that we should wait until “enough users complain that they have to turn it on” before we turn it on by default.

Stolee later sent a version 2 of the patch series improving the tests, then a version 3 improving the documentation, and a version 4 with a few code and commit message improvements.

Junio and Stolee discussed how the mark_trees_uninteresting_sparse() function is implemented in the first patch, and how a variable is named in this function.

They also discussed the purpose of patches 2 and 3 and agreed that they should be merged and what the related tests should do.

Additionally, Junio suggested a number of small code improvements in the last patch. Especially he suggested to get rid of a global variable that was unused. Ramsay Jones, who regularly uses the sparse tool and his own script on the Git code base to find errors, had also found this unused variable separately.

Ævar Arnfjörð Bjarmason chimed in to ask for a clarification about which step the patch speeds up, and if a progress bar should be added while the user is waiting during this step, and how this step should be named on the command line interface. It seems though that some preliminary work would be needed to untangle the steps during which a progress bar is already displayed.

Stolee eventually sent a version 5 of the patch series on January 16th which has since been merged and is in the recently released Git v2.21.0.


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This edition of Git Rev News was curated by Christian Couder <>, Jakub Narębski <>, Markus Jansen <> and Gabriel Alcaras <> with help from David Pursehouse and Luca Milanesio.