From 177361acaeaeeea49a79aa764cba0ebaebe5d80a Mon Sep 17 00:00:00 2001
From: Dillard Blom <dillard.blom@ensembia.com>
Date: Wed, 21 Oct 2026 09:08:50 +0200
Subject: [PATCH] Index load keeps the index when it refuses an empty listing;
 counters of unchanged tables are repaired too, never moved backwards

---
 lib/Db/DbDumper.php          | 12 +++++++++---
 lib/Repository/BlobIndex.php |  3 ++-
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/lib/Db/DbDumper.php b/lib/Db/DbDumper.php
index f99da8f..b0918f7 100644
--- a/lib/Db/DbDumper.php
+++ b/lib/Db/DbDumper.php
@@ -216,7 +216,8 @@ final class DbDumper {
 				}
 				$report['restored'][] = $table;
 			}
-			$this->restoreSequences($manifest['sequences'] ?? [], $report['missing'], $report['restored']);
+			// unchanged tables too: a restore that stopped earlier may have left their counters at 1
+			$this->restoreSequences($manifest['sequences'] ?? [], $report['missing'], array_merge($report['restored'], $report['skipped']));
 			$this->resumeForeignKeys($foreignKeys);
 			$this->db->commit();
 			// Foreign keys of the tables created above, now their rows are in. Not inside the
@@ -575,7 +576,7 @@ final class DbDumper {
 
 	/**
 	 * @param list<string> $leftOut tables not restored (--skip-missing-tables): they do not exist here
-	 * @param list<string> $restored tables restored: their other counters go after their data
+	 * @param list<string> $restored tables restored or unchanged: their other counters go after their data
 	 */
 	private function restoreSequences(array $sequences, array $leftOut = [], array $restored = []): void {
 		if (!$this->db->getDatabasePlatform() instanceof \Doctrine\DBAL\Platforms\PostgreSQLPlatform) {
@@ -616,7 +617,12 @@ final class DbDumper {
 			}
 			$max = (int)$this->db->fetchOne(sprintf('SELECT COALESCE(MAX(%s), 0) FROM %s',
 				$this->db->quoteIdentifier($r['column_name']), $this->db->quoteIdentifier($r['table_name'])));
-			$this->db->executeQuery('SELECT setval(CAST(? AS regclass), ?, false)', [$r['seq'], $max + 1]);
+			// never backwards: a counter already past the data stays where it is
+			$state = $this->db->fetchAssociative('SELECT last_value, is_called FROM ' . self::sequenceIdentifier($r['seq']));
+			$next = $state === false ? 1 : (int)$state['last_value'] + ($state['is_called'] ? 1 : 0);
+			if ($next <= $max) {
+				$this->db->executeQuery('SELECT setval(CAST(? AS regclass), ?, false)', [$r['seq'], $max + 1]);
+			}
 		}
 	}
 }
diff --git a/lib/Repository/BlobIndex.php b/lib/Repository/BlobIndex.php
index 32ca142..fc8e844 100644
--- a/lib/Repository/BlobIndex.php
+++ b/lib/Repository/BlobIndex.php
@@ -94,7 +94,6 @@ final class BlobIndex {
 	 */
 	public function load(bool $verify = false, ?callable $progress = null): void {
 		$hadIndex = $this->blobs !== [];
-		$this->blobs = [];
 		$cached = $verify ? [] : ($this->cache?->all($this->repositoryId) ?? []);
 		$present = [];
 		$this->downloaded = 0;
@@ -114,6 +113,8 @@ final class BlobIndex {
 		if ($present === [] && ($hadIndex || $cached !== [] || ($verify && ($this->cache?->all($this->repositoryId) ?? []) !== []))) {
 			throw new BackendException('The location listed no index files, while some are known: not trusting that listing');
 		}
+		// only now: an empty listing that was refused above leaves the index as it was
+		$this->blobs = [];
 		$this->loaded = $present;
 		// The rest is downloaded several at a time where the location allows it: on a large
 		// repository these are tens of thousands of small files. getMany() keeps their order, so