From: Johannes Schindelin <johannes.schindelin@xxxxxx> In 6e773527b6b (sparse-index: convert from full to sparse, 2021-03-30), we introduced initial support for a sparse index, and were careful to avoid converting to a sparse index in the presence of a split index. However, when we _just_ read a freshly-initialized index, it might not contain a split index even if _writing_ it will add one by virtue of being asked for via the `GIT_TEST_SPLIT_INDEX` variable. We did not notice any problems with checking _only_ for `split_index` (and not `GIT_TEST_SPLIT_INDEX`) right until both `vd/sparse-sparsity-fix-on-read` _and_ `vd/sparse-reset` were merged. Those two topics' interplay triggers a bug in conjunction with running t1091.15 when `GIT_TEST_SPLIT_INDEX=true` in the following way: `vd/sparse-sparsity-fix-on-read` ensures that the index is made sparse right after reading, and `vd/sparse-reset` ensures that the index is made non-sparse again unless running in the `--soft` mode. Since the split index feature is incompatible with the sparse index feature, we see a symptom like this: fatal: position for replacement 4 exceeds base index size 4 Let's fix this by avoiding the conversion to a sparse index when `GIT_TEST_SPLIT_INDEX=true`. Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx> --- sparse-index.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sparse-index.c b/sparse-index.c index a1d505d50e9..08f54747bb4 100644 --- a/sparse-index.c +++ b/sparse-index.c @@ -136,7 +136,7 @@ static int is_sparse_index_allowed(struct index_state *istate, int flags) /* * The sparse index is not (yet) integrated with a split index. */ - if (istate->split_index) + if (istate->split_index || git_env_bool("GIT_TEST_SPLIT_INDEX", 0)) return 0; /* * The GIT_TEST_SPARSE_INDEX environment variable triggers the -- gitgitgadget