repack: teach MIDX retention about geometric rollups
When writing an incremental MIDX, existing_packs_retain_midx_packs() marks packs in the existing MIDX chain as retained. This keeps them from being deleted by the later existing_packs deletion pass, since retained MIDX layers may still refer to those packs. Geometric repacks need a narrower rule. Packs below the split are rolled up into the newly-written pack, and should remain eligible for deletion even if the old MIDX chain mentions them. Packs above the split were marked as retained by the previous commit. Teach existing_packs_retain_midx_packs() to skip packs which are part of the geometric rollup. This does not change the current caller's behavior, since geometric repacks do not yet use the existing_packs deletion path. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Taylor Blau committed
Jun 26, 2026 at 15:02 UTC
5ff781e9fa3cfea4ac008c7e0e06a5f720b78060
3 files changed
+44
-4
builtin/repack.c
+1
-1
@@ -576,7 +576,7 @@ int cmd_repack(int argc,
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if (delete_redundant && pack_everything & ALL_INTO_ONE) {
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if (write_midx == REPACK_WRITE_MIDX_INCREMENTAL)
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- existing_packs_retain_midx_packs(&existing);
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+ existing_packs_retain_midx_packs(&existing, &geometry);
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existing_packs_mark_for_deletion(&existing, &names);
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}
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repack.c
+41
-2
@@ -292,6 +292,39 @@ void existing_packs_mark_for_deletion(struct existing_packs *existing,
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&existing->cruft_packs);
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}
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+static int pack_geometry_contains_pack(struct packed_git **packs,
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+ uint32_t packs_nr,
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+ const char *base)
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+{
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+ struct strbuf buf = STRBUF_INIT;
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+ uint32_t i;
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+
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+ for (i = 0; i < packs_nr; i++) {
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+ strbuf_reset(&buf);
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+ strbuf_addstr(&buf, pack_basename(packs[i]));
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+ strbuf_strip_suffix(&buf, ".pack");
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+
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+ if (!strcmp(buf.buf, base)) {
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+ strbuf_release(&buf);
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+ return 1;
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+ }
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+ }
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+
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+ strbuf_release(&buf);
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+ return 0;
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+}
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+
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+static int pack_geometry_contains_rollup(const struct pack_geometry *geometry,
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+ const char *base)
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+{
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+ if (!geometry || !geometry->split_factor)
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+ return 0;
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+
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+ return pack_geometry_contains_pack(geometry->pack, geometry->split, base) ||
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+ pack_geometry_contains_pack(geometry->promisor_pack,
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+ geometry->promisor_split, base);
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+}
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+
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/*
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* Mark every pack that is referenced by the existing MIDX chain as
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* retained, so that a subsequent call to
@@ -300,9 +333,12 @@ void existing_packs_mark_for_deletion(struct existing_packs *existing,
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* This is used when writing an incremental MIDX layer on top of an
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* existing chain: retained layers continue to reference the same
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* packs on disk, so those packs must not be unlinked even if the
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- * freshly-written pack supersedes them.
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+ * freshly-written pack supersedes them. When doing a geometric repack,
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+ * packs below the split are rewritten into the new MIDX tip and should
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+ * remain eligible for deletion.
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*/
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-void existing_packs_retain_midx_packs(struct existing_packs *existing)
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+void existing_packs_retain_midx_packs(struct existing_packs *existing,
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+ const struct pack_geometry *geometry)
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{
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struct string_list_item *item;
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struct strbuf buf = STRBUF_INIT;
@@ -315,6 +351,9 @@ void existing_packs_retain_midx_packs(struct existing_packs *existing)
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strbuf_strip_suffix(&buf, ".pack");
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strbuf_strip_suffix(&buf, ".idx");
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+ if (pack_geometry_contains_rollup(geometry, buf.buf))
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+ continue;
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+
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found = string_list_lookup(&existing->non_kept_packs, buf.buf);
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if (found)
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existing_packs_mark_retained(found);
repack.h
+2
-1
@@ -87,7 +87,8 @@ void existing_packs_retain_from_geometry(struct existing_packs *existing,
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const struct pack_geometry *geometry);
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void existing_packs_mark_for_deletion(struct existing_packs *existing,
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struct string_list *names);
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-void existing_packs_retain_midx_packs(struct existing_packs *existing);
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+void existing_packs_retain_midx_packs(struct existing_packs *existing,
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+ const struct pack_geometry *geometry);
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void existing_packs_remove_redundant(struct existing_packs *existing,
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const char *packdir,
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bool wrote_incremental_midx);