[PATCH 0/2] sparse-index: expand/collapse based on 'index.sparse'

This series updates do_read_index to use the index.sparse config setting when determining whether the index should be expanded or collapsed. If the command & repo allow use of a sparse index, index.sparse is enabled, and a full index is read from disk, the index is collapsed before returning to the caller. Conversely, if index.sparse is disabled but the index read from disk is sparse, the index is expanded before returning. This allows index.sparse to control use of the sparse index in addition to its existing control over how the index is written to disk. It also introduces the ability to enable/disable the sparse index on a command-by-command basis (e.g., allowing a user to troubleshoot a sparse-aware command with '-c index.sparse=false' [1]).

While testing this change, a bug was found in 'test-tool read-cache' in which config settings for the repository were not initialized before preparing the repo settings. This caused index.sparse to always be 'false' when using the test helper in a cone-mode sparse checkout, breaking tests in t1091 and t1092. The issue is fixed by moving prepare_repo_settings after config setup.

[1] https://lore.kernel.org/git/cc60c6e7-ecef-ae22-8ec7-ab290ff2b830@gmail.com/

Thanks! -Victoria

Victoria Dye (2):
  test-read-cache.c: prepare_repo_settings after config init
  sparse-index: update index read to consider index.sparse config

 read-cache.c                             |  5 +++-
 t/helper/test-read-cache.c               |  5 ++--
 t/t1092-sparse-checkout-compatibility.sh | 31 ++++++++++++++++++++++++
 3 files changed, 38 insertions(+), 3 deletions(-)

base-commit: f443b226ca681d87a3a31e245a70e6bc2769123c
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1059%2Fvdye%2Fsparse%2Findex-sparse-config-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1059/vdye/sparse/index-sparse-config-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1059