keep imported save cache on export

Red restores the current-map cache from SRAM before Continue. Dropping the import template made a later export boot with zeroed map data.

src/save_convert/SaveConvert.lua

@@ -116,13 +116,12 @@ local function defaultsSave()
 end
 
 -- Merge a GenSave.decode() result over the new-game defaults, exactly the
--- way convert.lua did, then stamp the requested version.  The 32768-byte
--- import template GenSave stashes as `rawImport` and the decode `warnings`
--- are dropped here: neither belongs in a serialized slot file (a fresh
--- export always starts zero-filled -- see GenSave.lua's header).
+-- way convert.lua did, then stamp the requested version.  Keep the imported
+-- SRAM image with the slot: Pokémon Red restores its saved current-map cache
+-- before Continue, and an export needs that unmodeled data to remain bootable.
+-- Decode warnings are only import diagnostics and do not belong in the slot.
 local function mergeDefaults(decoded, version)
   decoded.warnings = nil
-  decoded.rawImport = nil
   local save = defaultsSave()
   for k, v in pairs(decoded) do save[k] = v end
   save.lastHeal = { map = save.player.map, x = save.player.x, y = save.player.y }

tests/engine/save_file_io_tests.lua

@@ -96,7 +96,14 @@ local function syntheticSave(name)
     moves = { { id = "TACKLE", pp = 35, ppUps = 0 } },
     nickname = "SQ", ot = name, otId = seed.player.id, catchRate = 45,
   } }
-  return GenSave.encode(seed, data, nil)
+  -- The current-map view pointer is part of wMainData's map cache, not a
+  -- modeled save field.  Pokémon Red restores that cache before Continue,
+  -- so it is a useful canary for the import -> slot -> export path.
+  local raw = GenSave.encode(seed, data, nil)
+  local cacheOff = OFF.mainData + 104
+  local cacheTemplate = raw:sub(1, cacheOff) .. string.char(0xA5)
+    .. raw:sub(cacheOff + 2)
+  return GenSave.encode(seed, data, cacheTemplate)
 end
 
 -- ---------------------------------------------- importToSlot -> listSlots
@@ -149,6 +156,8 @@ do
   eq(outBytes and #outBytes, GenSave.SAVE_SIZE, "the export is exactly 32768 bytes")
   check(outBytes and mainChecksumValid(outBytes),
     "the export carries a valid main-data checksum")
+  eq(outBytes and outBytes:byte(OFF.mainData + 105), 0xA5,
+    "the export keeps the saved current-map cache")
 
   -- the export re-imports to an equivalent save
   local re = SaveConvert.importSav(outBytes, "red")

tests/save_convert_tests.lua

@@ -297,9 +297,10 @@ check(scSave and scSave.lastHeal and scSave.lastHeal.map == scSave.player.map,
       "SaveConvert.importSav: lastHeal derives from the decoded position")
 check(scSave and scSave.lastOutdoor and scSave.lastOutdoor.id ~= nil,
       "SaveConvert.importSav: lastOutdoor is set")
--- the import template + decode warnings never leak into the slot table
-check(scSave and scSave.rawImport == nil and scSave.warnings == nil,
-      "SaveConvert.importSav: rawImport/warnings stripped from the returned table")
+-- The original SRAM image carries the current-map cache that Red restores on
+-- Continue, while decode warnings are only import diagnostics.
+check(scSave and type(scSave.rawImport) == "string" and scSave.warnings == nil,
+      "SaveConvert.importSav: keeps the SRAM template but drops warnings")
 
 -- size / type validation
 local badSize, badSizeErr = SaveConvert.importSav("too short", 2)