From d388fbf665677ac5c08761a93e51521e36de0c47 Mon Sep 17 00:00:00 2001
From: Alistair-Afton <AlistairDev@gmx.de>
Date: Thu, 17 Sep 2026 22:52:16 +0200
Subject: [PATCH] quickfix: repair unassigned site_id on reclaimed fortresses

---
 data/init/onMapLoad.default.init   |  2 ++
 docs/changelog.txt                 |  1 +
 library/lua/quickfix.lua           | 17 +++++++++++++++++
 test/modules/quickfix_fortress.lua | 26 ++++++++++++++++++++++++++
 4 files changed, 46 insertions(+)
 create mode 100644 test/modules/quickfix_fortress.lua

diff --git a/data/init/onMapLoad.default.init b/data/init/onMapLoad.default.init
index 44986a044c..fb5912fea4 100644
--- a/data/init/onMapLoad.default.init
+++ b/data/init/onMapLoad.default.init
@@ -4,3 +4,5 @@
 # Please do not edit this file directly. It will be overwritten with new
 # defaults when you update DFHack. Instead, add your configuration to
 # dfhack-config/init/onMapLoad.init
+
+lua require('quickfix').repair_site_id()
diff --git a/docs/changelog.txt b/docs/changelog.txt
index da5a2d4d7c..e9f9c4c381 100644
--- a/docs/changelog.txt
+++ b/docs/changelog.txt
@@ -76,6 +76,7 @@ Template for new versions:
 - `timestream`: deal properly with units who have breathing difficulties
 - `stocks`: overlay now resets scroll position when collapsing categories so the item list is no longer left blank and unscrollable
 - Fixed persistent site data API (``dfhack.persistent.saveSiteData``/``getSiteData``) failing on newly reclaimed fortresses until the first save
+- ``quickfix``: repair ``plotinfo.site_id`` on load when DF leaves it unassigned on reclaimed fortresses
 
 ## Misc Improvements
 - Added ``Coord2d`` and ``Coord3d`` C++ templates, providing a standard set operations for 2-tuples and 3-tuples of any numeric type
diff --git a/library/lua/quickfix.lua b/library/lua/quickfix.lua
index f46d03ef66..59880862b2 100644
--- a/library/lua/quickfix.lua
+++ b/library/lua/quickfix.lua
@@ -27,4 +27,21 @@ function set_entity_race_references()
     print(('quickfix: fixed %d unset entity race reference(s)'):format(count))
 end
 
+-- on reclaimed fortresses DF fails to assign plotinfo.site_id until the
+-- first save, breaking anything that needs the site id; fortress_site is
+-- set at embark, so restore the invariant from it
+-- called from onMapLoad.default.init
+function repair_site_id()
+    local plotinfo = df.global.plotinfo
+    if plotinfo.site_id ~= -1 then
+        return
+    end
+    local site = plotinfo.main.fortress_site
+    if not site then
+        return
+    end
+    plotinfo.site_id = site.id
+    print(('quickfix: repaired unassigned site_id (now %d)'):format(site.id))
+end
+
 return _ENV
diff --git a/test/modules/quickfix_fortress.lua b/test/modules/quickfix_fortress.lua
new file mode 100644
index 0000000000..104ba9d650
--- /dev/null
+++ b/test/modules/quickfix_fortress.lua
@@ -0,0 +1,26 @@
+config.mode = 'fortress'
+config.target = 'core'
+
+local quickfix = require('quickfix')
+
+function test.repair_site_id_restores_fortress_site()
+    local plotinfo = df.global.plotinfo
+    local orig = plotinfo.site_id
+    local site = plotinfo.main.fortress_site
+    expect.ne(nil, site, 'no fortress site on this map')
+    if not site then return end
+
+    return dfhack.with_finalize(function()
+        plotinfo.site_id = orig
+    end, function()
+        plotinfo.site_id = -1
+        quickfix.repair_site_id()
+        expect.eq(site.id, plotinfo.site_id)
+    end)
+end
+
+function test.repair_site_id_noop_when_assigned()
+    local orig = df.global.plotinfo.site_id
+    quickfix.repair_site_id()
+    expect.eq(orig, df.global.plotinfo.site_id)
+end