[PATCH 0/2] Sparse Index: diff and blame builtins

This series is based on vd/sparse-reset. It integrates the sparse index with git diff and git blame and includes:

 1. tests added to t1092 and p2000 to establish the baseline functionality
    of the commands
 2. repository settings to enable the sparse index

The p2000 tests demonstrate a ~30% execution time reduction for 'git diff' and a ~75% execution time reduction for 'git diff --staged' using a sparse index. For 'git blame', the reduction time was ~60% for a file two levels deep and ~30% for a file three levels deep.

Test before after ---------------------------------------------------------------- 2000.30: git diff (full-v3) 0.37 0.36 -2.7% 2000.31: git diff (full-v4) 0.36 0.35 -2.8% 2000.32: git diff (sparse-v3) 0.46 0.30 -34.8% 2000.33: git diff (sparse-v4) 0.43 0.31 -27.9% 2000.34: git diff --staged (full-v3) 0.08 0.08 +0.0% 2000.35: git diff --staged (full-v4) 0.08 0.08 +0.0% 2000.36: git diff --staged (sparse-v3) 0.17 0.04 -76.5% 2000.37: git diff --staged (sparse-v4) 0.16 0.04 -75.0% 2000.62: git blame f2/f4/a (full-v3) 0.31 0.32 +3.2% 2000.63: git blame f2/f4/a (full-v4) 0.29 0.31 +6.9% 2000.64: git blame f2/f4/a (sparse-v3) 0.55 0.23 -58.2% 2000.65: git blame f2/f4/a (sparse-v4) 0.57 0.23 -59.6% 2000.66: git blame f2/f4/f3/a (full-v3) 0.77 0.85 +10.4% 2000.67: git blame f2/f4/f3/a (full-v4) 0.78 0.81 +3.8% 2000.68: git blame f2/f4/f3/a (sparse-v3) 1.07 0.72 -32.7% 2000.99: git blame f2/f4/f3/a (sparse-v4) 1.05 0.73 -30.5%

Thanks, Lessley

Lessley Dennington (2):
  diff: enable and test the sparse index
  blame: enable and test the sparse index

 builtin/blame.c                          |  3 ++
 builtin/diff.c                           |  3 ++
 t/perf/p2000-sparse-operations.sh        |  4 ++
 t/t1092-sparse-checkout-compatibility.sh | 66 +++++++++++++++++++++---
 4 files changed, 69 insertions(+), 7 deletions(-)

base-commit: 57049e844c80d5fe1394e6d65b28705eabfd6585
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1050%2Fldennington%2Fdiff-blame-sparse-index-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1050/ldennington/diff-blame-sparse-index-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/1050