Merge pull request #9289 from rouault/fix_9288

PMTiles: fix 'Non increasing tile_id' error when opening some files (fixes #9288)

Author: rouault

autotest/ogr/data/pmtiles/subset7_truncated.pmtiles

@@ -617,3 +617,15 @@ def test_ogr_pmtiles_read_corrupted_min_zoom_larger_than_30():
             ds = ogr.Open(tmpfilename)
         assert gdal.GetLastErrorMsg() == "Clamping max_zoom from 255 to 30"
         assert ds.GetMetadataItem("ZOOM_LEVEL") == "30"
+
+
+###############################################################################
+
+
+def test_ogr_pmtiles_read_with_many_directories():
+
+    ds = gdal.OpenEx(
+        "data/pmtiles/subset7_truncated.pmtiles", open_options=["ZOOM_LEVEL=0"]
+    )
+    lyr = ds.GetLayer(0)
+    assert lyr.GetFeatureCount() != 0

autotest/ogr/ogr_pmtiles.py

@@ -202,7 +202,9 @@ class OGRPMTilesTileIterator
     int m_nCurY = -1;
 
     // for sanity checks. Must be increasing when walking through entries
-    uint64_t m_nLastTileId = 0;
+    static constexpr uint64_t INVALID_LAST_TILE_ID =
+        std::numeric_limits<uint64_t>::max();
+    uint64_t m_nLastTileId = INVALID_LAST_TILE_ID;
 
     // Computed values from zoom leven and min/max x/y
     uint64_t m_nMinTileId = std::numeric_limits<uint64_t>::max();

ogr/ogrsf_frmts/pmtiles/ogr_pmtiles.h

@@ -250,7 +250,7 @@ pmtiles::entry_zxy OGRPMTilesTileIterator::GetNextTile(uint32_t *pnRunLength)
                             static_cast<uint8_t>(m_nZoomLevel), m_nCurX,
                             m_nCurY);
                         m_nMaxTileId = m_nMinTileId;
-                        m_nLastTileId = 0;
+                        m_nLastTileId = INVALID_LAST_TILE_ID;
                         while (m_aoStack.size() > 1)
                             m_aoStack.pop();
                         const int nMinEntryIdx = find_tile_idx_lesser_or_equal(
@@ -323,7 +323,8 @@ pmtiles::entry_zxy OGRPMTilesTileIterator::GetNextTile(uint32_t *pnRunLength)
                     break;
                 }
 
-                if (sContext.sEntries[0].tile_id <= m_nLastTileId)
+                if (m_nLastTileId != INVALID_LAST_TILE_ID &&
+                    sContext.sEntries[0].tile_id <= m_nLastTileId)
                 {
                     CPLError(CE_Failure, CPLE_AppDefined,
                              "Non increasing tile_id");