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dbgrbydbalance: Fixed height=0 corner case

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This use of 0 here as a no-height indicator is probably not a good idea.
If this loop ever encounters height=0, it will reset progress, and
possibly calculate an incorrect min_height.

Fortunately this can't actually happen with our current rbyds. Only the
single element rbyd has height=0, and, lacking a tree, it is trivially
balanced. But this is the sort of sleeping bug that risks becoming a
real bug in the future, so might as well fix.

Using -1 (UINT_MAX) as a default value for min_height avoids this.
This commit is contained in:
Christopher Haster
2025-07-17 14:11:31 -05:00
parent 9f246b33a8
commit b0ac5bf9e6
1 changed files with 8 additions and 14 deletions
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lfs3.c
+8 -14
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@@ -3056,9 +3056,9 @@ static int lfs3_rbyd_fetch_(lfs3_t *lfs3,
#ifdef LFS3_DBGRBYDBALANCE
lfs3_srid_t rid = -1;
lfs3_tag_t tag = 0;
lfs3_size_t min_height = 0;
lfs3_size_t min_height = -1;
lfs3_size_t max_height = 0;
lfs3_size_t min_bheight = 0;
lfs3_size_t min_bheight = -1;
lfs3_size_t max_bheight = 0;
while (true) {
lfs3_rheight_t rheight;
@@ -3074,19 +3074,13 @@ static int lfs3_rbyd_fetch_(lfs3_t *lfs3,
}
// find the min/max height and bheight
min_height = (min_height)
? lfs3_min(min_height, rheight.height)
: rheight.height;
max_height = (max_height)
? lfs3_max(max_height, rheight.height)
: rheight.height;
min_bheight = (min_bheight)
? lfs3_min(min_bheight, rheight.bheight)
: rheight.bheight;
max_bheight = (max_bheight)
? lfs3_max(max_bheight, rheight.bheight)
: rheight.bheight;
min_height = lfs3_min(min_height, rheight.height);
max_height = lfs3_max(max_height, rheight.height);
min_bheight = lfs3_min(min_bheight, rheight.bheight);
max_bheight = lfs3_max(max_bheight, rheight.bheight);
}
min_height = (min_height == (lfs3_size_t)-1) ? 0 : min_height;
min_bheight = (min_bheight == (lfs3_size_t)-1) ? 0 : min_bheight;
LFS3_DEBUG("Fetched rbyd 0x%"PRIx32".%"PRIx32" w%"PRId32", "
"height %"PRId32"-%"PRId32", "
"bheight %"PRId32"-%"PRId32,