Add notification case: missing nemesis records

changelog.txt

@@ -29,6 +29,7 @@ Template for new versions:
 ## New Tools
 
 ## New Features
+- `gui/notify`: new notification type: missing nemesis records; displays a warning message and some recommended steps to test for game corruption.
 
 ## Fixes
 

internal/notify/notifications.lua

@@ -334,8 +334,78 @@ local function save_popup()
     end
 end
 
+local function get_citizens_with_missing_nemesis_records()
+    local citizens = {}
+    for _, unit in ipairs(dfhack.units.getCitizens(true)) do
+        if dfhack.units.getGeneralRef(unit, df.general_ref_type.IS_NEMESIS) then
+            local nid = dfhack.units.getGeneralRef(unit, df.general_ref_type.IS_NEMESIS).nemesis_id
+            if df.nemesis_record.find(nid) == nil then
+                table.insert(citizens, '  ' .. dfhack.units.getReadableName(unit))
+            end
+        end
+    end
+    if #citizens == 0 then return end
+    table.insert(citizens, 1, '\n' .. 'These citizens are missing nemesis records:')
+    table.insert(citizens, '\n')
+    return table.concat(citizens, '\n')
+end
+
 -- the order of this list controls the order the notifications will appear in the overlay
 NOTIFICATIONS_BY_IDX = {
+    {
+        name='missing_nemesis',
+        desc='Reports missing nemesis records, indicating possible game corruption.',
+        default=true,
+        fn = function()
+            local count = df.global.nemesis_next_id - #df.global.world.nemesis.all
+            if count == 0 then return end
+            return string.format('missing %d nemesis record%s', count, (count == 1 and '' or 's'))
+        end,
+        on_click=function()
+            local message = {}
+            table.insert(message,  -- indentation MATTERS here!
+                    (([[THE GAME MAY BE CORRUPT!  Or it may be fine.
+                        This notification is experimental.
+
+                        Nemesis records are missing from the world.
+                        Missing nemesis records have been known to
+                        cause crashes during game save or quit.
+
+                        ]] ):gsub(string.rep(' ',24), '')) )
+            local redtext = get_citizens_with_missing_nemesis_records()
+            if redtext ~= nil and redtext ~= '' then
+                for _, line in ipairs(redtext:split('\n')) do
+                    table.insert(message, { pen = COLOR_LIGHTRED, text = line })
+                    table.insert(message, NEWLINE)
+                end
+            end
+            table.insert(message,  -- indentation MATTERS here!
+                    (([[Suggested course of action:
+                        * Read all of these steps before continuing.
+
+                        * Press `Esc` to show the "Dwarf Fortress"
+                          menu, and choose "Save and continue playing".
+                          Name the savegame "corrupt-nemesis".
+
+                        * If the save succeeds, open that menu again
+                          and choose "Quit without saving".  This may
+                          crash the game!  If the game doesn't crash,
+                          choose "Quit" at the main menu.
+
+                        * Restart Dwarf Fortress and try to load the
+                          "corrupt-nemesis" savegame.
+
+                        * If it loads, things are probably fine, and
+                          you can disable this notification by clicking
+                          the gear symbol to get the notifications
+                          settings, then clicking on "missing_nemesis"
+                          to change it to Disabled.
+                          ]] ):trim():gsub(string.rep(' ',24), '')) )
+            dlg.showMessage(get_citizens_with_missing_nemesis_records() ~= ''
+                and 'Citizens are missing nemesis records' or 'Missing nemesis records',
+                message, COLOR_WHITE)
+        end,
+    },
     {
         name='stuck_squad',
         desc='Notifies when a squad is stuck on the world map.',