Fix PushStyleVar aliasing the caller's ImVec2 into the style; fix DebugNodeFontGlyph crash

build/ImGui.linemap.json

@@ -1 +1 @@
-[[12, "imgui.lua"], [13734, "imgui_demo.lua"], [14667, "imgui_demo_2.lua"], [17742, "imgui_demo_apps.lua"], [19001, "imgui_demo_tools.lua"], [20327, "imgui_demo_widgets.lua"], [22251, "imgui_docking.lua"], [25379, "imgui_dragdrop.lua"], [25671, "imgui_draw.lua"], [30859, "imgui_h.lua"], [33072, "imgui_impl_roblox.lua"], [33859, "imgui_impl_roblox_fonts.lua"], [34637, "imgui_internal.lua"], [37807, "imgui_tables.lua"], [42154, "imgui_tabs.lua"], [43321, "imgui_widgets.lua"], [51845, "imstb_rectpack.lua"], [52291, "imstb_textedit.lua"], [53532, "imstb_truetype.lua"], [56000, "imstd_minstdio.lua"]]
+[[12, "imgui.lua"], [13741, "imgui_demo.lua"], [14674, "imgui_demo_2.lua"], [17749, "imgui_demo_apps.lua"], [19008, "imgui_demo_tools.lua"], [20334, "imgui_demo_widgets.lua"], [22258, "imgui_docking.lua"], [25386, "imgui_dragdrop.lua"], [25678, "imgui_draw.lua"], [30866, "imgui_h.lua"], [33079, "imgui_impl_roblox.lua"], [33866, "imgui_impl_roblox_fonts.lua"], [34644, "imgui_internal.lua"], [37814, "imgui_tables.lua"], [42161, "imgui_tabs.lua"], [43328, "imgui_widgets.lua"], [51852, "imstb_rectpack.lua"], [52298, "imstb_textedit.lua"], [53539, "imstb_truetype.lua"], [56007, "imstd_minstdio.lua"]]

build/ImGui.luau

@@ -8855,7 +8855,11 @@ function ImGui.PushStyleVar(idx, val)
     end
     local var = g.Style[var_info.Key]
     g.StyleVarStack:push_back(ImGuiStyleMod(idx, var))
-    g.Style[var_info.Key] = val
+    if type(val) == "number" then
+        g.Style[var_info.Key] = val
+    else -- copy into the style's own ImVec2: storing the caller's vector would alias it into the style forever
+        var.x = val.x; var.y = val.y
+    end
 end
 
 --- @param idx   ImGuiStyleVar
@@ -19130,8 +19134,8 @@ function ImGui.DebugNodeFontGlyph(font, glyph)
     ImGui.Text("Pos: (%.2f,%.2f)->(%.2f,%.2f)", glyph.X0, glyph.Y0, glyph.X1, glyph.Y1)
     ImGui.Text("UV: (%.3f,%.3f)->(%.3f,%.3f)", glyph.U0, glyph.V0, glyph.U1, glyph.V1)
     if glyph.PackId >= 0 then
-        local r = ImFontAtlasPackGetRect(font.OwnerAtlas, glyph.PackId)
+        local r = { uv0 = ImVec2(), uv1 = ImVec2() }
-        if r then ImGui.Text("PackId: 0x%X (%dx%d rect at %d,%d)", glyph.PackId, r.w, r.h, r.x, r.y) end
+        if font.OwnerAtlas:GetCustomRect(glyph.PackId, r) then ImGui.Text("PackId: 0x%X (%dx%d rect at %d,%d)", glyph.PackId, r.w, r.h, r.x, r.y) end
     end
     ImGui.Text("SourceIdx: %d", glyph.SourceIdx)
 end

imgui/imgui.lua

@@ -8844,7 +8844,11 @@ function ImGui.PushStyleVar(idx, val)
     end
     local var = g.Style[var_info.Key]
     g.StyleVarStack:push_back(ImGuiStyleMod(idx, var))
-    g.Style[var_info.Key] = val
+    if type(val) == "number" then
+        g.Style[var_info.Key] = val
+    else -- copy into the style's own ImVec2: storing the caller's vector would alias it into the style forever
+        var.x = val.x; var.y = val.y
+    end
 end
 
 --- @param idx   ImGuiStyleVar

imgui/imgui_demo_tools.lua

@@ -127,8 +127,8 @@ function ImGui.DebugNodeFontGlyph(font, glyph)
     ImGui.Text("Pos: (%.2f,%.2f)->(%.2f,%.2f)", glyph.X0, glyph.Y0, glyph.X1, glyph.Y1)
     ImGui.Text("UV: (%.3f,%.3f)->(%.3f,%.3f)", glyph.U0, glyph.V0, glyph.U1, glyph.V1)
     if glyph.PackId >= 0 then
-        local r = ImFontAtlasPackGetRect(font.OwnerAtlas, glyph.PackId)
+        local r = { uv0 = ImVec2(), uv1 = ImVec2() }
-        if r then ImGui.Text("PackId: 0x%X (%dx%d rect at %d,%d)", glyph.PackId, r.w, r.h, r.x, r.y) end
+        if font.OwnerAtlas:GetCustomRect(glyph.PackId, r) then ImGui.Text("PackId: 0x%X (%dx%d rect at %d,%d)", glyph.PackId, r.w, r.h, r.x, r.y) end
     end
     ImGui.Text("SourceIdx: %d", glyph.SourceIdx)
 end

tools/test/scripts/t_style_leak.luau

@@ -0,0 +1,46 @@
+-- Scrolls the demo with everything open (run with --open) and asserts no style value changes
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+local RunService = game:GetService("RunService")
+local G = require(ReplicatedStorage:WaitForChild("ImGui"))
+local ImGui = G.ImGui
+ImGui.CreateContext()
+ImGui.GetIO().ConfigFlags = bit32.bor(ImGui.GetIO().ConfigFlags, G.ImGuiConfigFlags.NavEnableKeyboard, G.ImGuiConfigFlags.DockingEnable)
+G.ImGui_ImplRoblox.Init()
+local style = ImGui.GetStyle()
+local function snap()
+    local t = {}
+    for k, v in pairs(style) do
+        if type(v) == "number" then t[k] = tostring(v)
+        elseif type(v) == "table" and getmetatable(v) ~= nil and v.x ~= nil then t[k] = v.x .. "," .. v.y; t[k .. "#id"] = v end
+    end
+    return t
+end
+local ref
+local frame = 0
+RunService.Stepped:Connect(function()
+    frame += 1
+    G.ImGui_ImplRoblox.NewFrame()
+    local w0 = ImGui.FindWindowByName("ImGui Sincerely Demo")
+    if w0 and frame > 2 then
+        local io = ImGui.GetIO()
+        -- sweep the mouse over the window so hover-only paths (tooltips etc.) run
+        io:AddMousePosEvent(w0.Pos.x + 30 + (frame * 37) % math.max(1, w0.Size.x - 60), w0.Pos.y + 40 + (frame * 53) % math.max(1, w0.Size.y - 80))
+        io:AddMouseWheelEvent(0, -1)
+    end
+    ImGui.NewFrame()
+    ImGui.DockSpaceOverViewport(0, nil, G.ImGuiDockNodeFlags.PassthruCentralNode)
+    ImGui.ShowDemoWindow(true)
+    ImGui.Begin("Hello, world!"); ImGui.Checkbox("Demo Window", true); ImGui.SliderFloat("float", 0, 0, 1); ImGui.Button("Button"); ImGui.End()
+    ImGui.EndFrame()
+    local w = ImGui.FindWindowByName("ImGui Sincerely Demo")
+
+    ImGui.Render()
+    G.ImGui_ImplRoblox.RenderDrawData(ImGui.GetDrawData())
+    if frame == 2 then ref = snap() end
+    if frame > 2 and ref then
+        for k, v in pairs(snap()) do
+            if not rawequal(ref[k], v) then error(("style.%s changed %s -> %s at frame %d"):format(k, tostring(ref[k]), tostring(v), frame)) end
+        end
+    end
+    if frame == ARG_FRAMES then print("STYLE OK") end
+end)