t1700: add tests for splitIndex.maxPercentChange

diff --git a/read-cache.c b/read-cache.c
index 732b7fe6113dfd8ca71be1fa00a4dd4b27f23f08..fd1c88aa0f52911dd3171e502887968eb187d8ea 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -2220,6 +2220,36 @@ static int write_shared_index(struct index_state *istate,
        return ret;
 }
 
+static const int default_max_percent_split_change = 20;
+
+static int too_many_not_shared_entries(struct index_state *istate)
+{
+       int i, not_shared = 0;
+       int max_split = git_config_get_max_percent_split_change();
+
+       switch (max_split) {
+       case -1:
+               /* not or badly configured: use the default value */
+               max_split = default_max_percent_split_change;
+               break;
+       case 0:
+               return 1; /* 0% means always write a new shared index */
+       case 100:
+               return 0; /* 100% means never write a new shared index */
+       default:
+               break; /* just use the configured value */
+       }
+
+       /* Count not shared entries */
+       for (i = 0; i < istate->cache_nr; i++) {
+               struct cache_entry *ce = istate->cache[i];
+               if (!ce->index)
+                       not_shared++;
+       }
+
+       return (int64_t)istate->cache_nr * max_split < (int64_t)not_shared * 100;
+}
+
 int write_locked_index(struct index_state *istate, struct lock_file *lock,
                       unsigned flags)
 {
@@ -2237,6 +2267,8 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
                if ((v & 15) < 6)
                        istate->cache_changed |= SPLIT_INDEX_ORDERED;
        }
+       if (too_many_not_shared_entries(istate))
+               istate->cache_changed |= SPLIT_INDEX_ORDERED;
        if (istate->cache_changed & SPLIT_INDEX_ORDERED) {
                int ret = write_shared_index(istate, lock, flags);
                if (ret)