Prevent Guide detail render crashes

mod/kanto_gear/main.lua

@@ -3419,11 +3419,11 @@ return function(mod)
       end
     end
     if not row then displayRuntime.guideDetail = nil; drawGuide(); return end
-    displayRuntime.guideDetail.page = math.max(1,
-      math.min(displayRuntime.guideDetail.page, row.detailPages))
+    local pages = math.max(1, tonumber(row.detailPages) or 1)
+    local current = tonumber(displayRuntime.guideDetail.page) or 1
+    displayRuntime.guideDetail.page = math.max(1, math.min(current, pages))
     header(THEME:format("WHERE %d/%d", displayRuntime.guideDetail.page,
-      row.detailPages),
-      true, row.detailPages > 1)
+      pages), true, pages > 1)
     text(fit(row.name, 17), 5, 24, INK)
     text(row.availability == "now" and THEME:translate("NOW")
       or row.availability == "time" and guide.time
@@ -4551,8 +4551,7 @@ return function(mod)
     end
   end
 
-  local function draw()
-    G.push("all")
+  displayRuntime.drawContents = function()
     G.setCanvas(canvas)
     G.origin()
     G.setScissor()
@@ -4632,7 +4631,13 @@ return function(mod)
       outline(1, 1, WIDTH - 2, HEIGHT - 2, INK)
     end
     G.setCanvas()
+  end
+
+  local function draw()
+    G.push("all")
+    local ok, err = pcall(displayRuntime.drawContents)
     G.pop()
+    if not ok then error(err, 0) end
   end
 
   local function pumpDisplay()
@@ -5198,9 +5203,11 @@ return function(mod)
         end
       end
       if row and row.detailPages > 1 then
-        displayRuntime.guideDetail.page = carouselSubpage(
-          displayRuntime.guideDetail.page, row.detailPages, direction)
-        dirty = true
+        local nextPage = carouselSubpage(displayRuntime.guideDetail.page,
+          row.detailPages, direction)
+        if nextPage then
+          displayRuntime.guideDetail.page, dirty = nextPage, true
+        end
       end
       return
     end
@@ -5465,13 +5472,15 @@ return function(mod)
           end
         end
         if row and row.detailPages > 1 then
+          local nextPage
           if x >= 22 and x < 48 then
-            displayRuntime.guideDetail.page = carouselSubpage(
+            nextPage = carouselSubpage(
               displayRuntime.guideDetail.page, row.detailPages, -1)
           elseif x >= 80 and x < 106 then
-            displayRuntime.guideDetail.page = carouselSubpage(
+            nextPage = carouselSubpage(
               displayRuntime.guideDetail.page, row.detailPages, 1)
           end
+          if nextPage then displayRuntime.guideDetail.page = nextPage end
         end
       end
       dirty = true

mod/kanto_gear/tests/gen2_compat_test.lua

@@ -318,12 +318,71 @@ do
       if name == target then return value end
     end
   end
+  local function setUpvalue(fn, target, value)
+    for index = 1, debug.getinfo(fn, "u").nups do
+      if debug.getupvalue(fn, index) == target then
+        debug.setupvalue(fn, index, value)
+        return true
+      end
+    end
+  end
   local inputHook
   for _, entry in ipairs(run.loader.hooks.chains["input.step"] or {}) do
     if entry.owner == "kanto_gear" then inputHook = entry.callback end
   end
   local changePage = upvalue(upvalue(inputHook, "pollTriggerTabs"),
     "changePage")
+
+  local composeHook
+  for _, entry in ipairs(run.loader.hooks.chains["render.compose"] or {}) do
+    if entry.owner == "kanto_gear" then composeHook = entry.callback end
+  end
+  local touchEvent = upvalue(composeHook, "touchEvent")
+  local tap = upvalue(touchEvent, "tap")
+  local displayRuntime = upvalue(changePage, "displayRuntime")
+  local guideData = upvalue(changePage, "guideData")
+  T.check(setUpvalue(changePage, "page", "GUIDE"),
+    "Guide regression can select the GUIDE tab")
+  T.check(guideData().rows[1].detailPages > 1,
+    "Guide regression fixture has multiple detail pages")
+  tap(10, 50)
+  T.eq(displayRuntime.guideDetail.page, 1,
+    "tapping a Guide row opens its first detail page")
+  changePage(-1)
+  T.eq(displayRuntime.guideDetail.page, 1,
+    "swiping back at the first detail boundary keeps a valid page")
+  tap(30, 10)
+  T.eq(displayRuntime.guideDetail.page, 1,
+    "tapping back at the first detail boundary keeps a valid page")
+  local lastDetailPage = guideData().rows[1].detailPages
+  displayRuntime.guideDetail.page = lastDetailPage
+  tap(90, 10)
+  T.eq(displayRuntime.guideDetail.page, lastDetailPage,
+    "tapping forward at the last detail boundary keeps a valid page")
+  displayRuntime.guideDetail = nil
+  setUpvalue(changePage, "page", "MAP")
+
+  local pumpDisplay = upvalue(composeHook, "pumpDisplay")
+  local draw = upvalue(pumpDisplay, "draw")
+  local drawContents = displayRuntime.drawContents
+  local push, pop = T.love.graphics.push, T.love.graphics.pop
+  local graphicsDepth = 0
+  T.love.graphics.push = function(...)
+    graphicsDepth = graphicsDepth + 1
+    return push(...)
+  end
+  T.love.graphics.pop = function(...)
+    graphicsDepth = graphicsDepth - 1
+    return pop(...)
+  end
+  displayRuntime.drawContents = function() error("expected draw failure") end
+  local ok = pcall(draw)
+  displayRuntime.drawContents = drawContents
+  T.love.graphics.push, T.love.graphics.pop = push, pop
+  T.check(not ok, "companion draw failures remain observable")
+  T.eq(graphicsDepth, 0,
+    "companion draw failures restore the graphics stack")
+
   for _ = 1, 6 do changePage(1) end
 
   local previousParty, previousIcons = game.save.party, run.data.gen2Icons