Preserve main skill selection across character reimports

Keep exact state matching for unchanged groups. When a group's gems change, relocate it by source skill and preferred slot, then restore the selected active effect after its skill list is rebuilt. Use the existing group guess only when the source skill disappears.

Addresses issue 10199.

Author: mcagnion

spec/System/TestImportReimport_spec.lua

@@ -55,6 +55,22 @@ describe("TestImportReimport", function()
 		}
 	end
 
+	local function pasteSocketGroups(mainSocketGroup, ...)
+		for _, lines in ipairs({ ... }) do
+			build.skillsTab:PasteSocketGroup(table.concat(lines, "\n") .. "\n")
+		end
+		build.mainSocketGroup = mainSocketGroup
+		runCallback("OnFrame")
+	end
+
+	local function makeImportItemWithGems(itemTypeLine, inventoryId, ...)
+		local socketedItems = { }
+		for index, gemName in ipairs({ ... }) do
+			socketedItems[index] = makeSocketedGemEntry(index - 1, gemName:match(" Support$") ~= nil, gemName, 20)
+		end
+		return makeImportItem(itemTypeLine, inventoryId, socketedItems, "test-import-item-" .. inventoryId)
+	end
+
 	local function reimportSocketedItemsWithOptions(itemTypeLine, inventoryId, socketedItems, clearItems)
 		build.importTab:ImportItemsAndSkills(buildImportPayload({
 			makeImportItem(itemTypeLine, inventoryId, socketedItems),
@@ -228,6 +244,52 @@ Blight 20/0  1
 		assert.is_false(groupsBySlot.Gloves.enabled)
 	end)
 
+	it("preserves the main socket group when supports change", function()
+		pasteSocketGroups(1,
+			{ "Slot: Body Armour", "Cleave 20/0  1", "Added Fire Damage 20/0 DISABLED 1" }
+		)
+
+		build.importTab:ImportItemsAndSkills(buildImportPayload({
+			makeImportItemWithGems("Rawhide Gloves", "Gloves", "Cleave"),
+			makeImportItemWithGems("Plate Vest", "BodyArmour", "Cleave", "Faster Attacks Support"),
+		}), false, true, true)
+		runCallback("OnFrame")
+
+		local mainSocketGroup = build.skillsTab.socketGroupList[build.mainSocketGroup]
+		assert.are.equal("Body Armour", mainSocketGroup.slot)
+		assert.is_true(mainSocketGroup.gemList[2].enabled)
+	end)
+
+	it("preserves a support-granted main skill when supports change", function()
+		pasteSocketGroups(1,
+			{ "Slot: Body Armour", "Cleave 20/0  1", "Prismatic Burst 20/0  1", "Added Fire Damage 20/0  1" }
+		)
+		build.skillsTab.socketGroupList[1].mainActiveSkill = 2
+
+		build.importTab:ImportItemsAndSkills(buildImportPayload({
+			makeImportItemWithGems("Plate Vest", "BodyArmour", "Cleave", "Prismatic Burst Support", "Faster Attacks Support"),
+		}), false, true, true)
+		runCallback("OnFrame")
+
+		local mainSocketGroup = build.skillsTab.socketGroupList[build.mainSocketGroup]
+		assert.are.equal("PrismaticBurst", mainSocketGroup.displaySkillList[mainSocketGroup.mainActiveSkill].activeEffect.grantedEffect.id)
+	end)
+
+	it("guesses a new main socket group when the previous main skill is gone", function()
+		pasteSocketGroups(1,
+			{ "Slot: Body Armour", "Cleave 20/0  1" },
+			{ "Slot: Boots", "Frostblink 20/0  1" }
+		)
+
+		build.importTab:ImportItemsAndSkills(buildImportPayload({
+			makeImportItemWithGems("Iron Greaves", "Boots", "Frostblink"),
+			makeImportItemWithGems("Rawhide Gloves", "Gloves", "Fireball", "Added Fire Damage Support"),
+		}), false, true, true)
+		runCallback("OnFrame")
+
+		assert.are.equal("Gloves", build.skillsTab.socketGroupList[build.mainSocketGroup].slot)
+	end)
+
 	it("preserves skill part selection when reimporting items and skills", function()
 		assertReimportPreservesSkillSubstate("Helmet", "Iron Hat", "Helm", "Blight", "skillPart", 2)
 	end)

src/Classes/ImportTab.lua

@@ -1267,6 +1267,22 @@ local function getSocketGroupReimportKey(socketGroup)
 	}, SOCKET_GROUP_REIMPORT_KEY_SEPARATOR)
 end
 
+local function findSocketGroupBySkillId(socketGroupList, skillId, preferredSlot)
+	local fallbackIndex
+	for index, socketGroup in ipairs(socketGroupList) do
+		for _, gem in ipairs(socketGroup.gemList) do
+			if gem.skillId == skillId then
+				if socketGroup.slot == preferredSlot then
+					return index
+				end
+				fallbackIndex = fallbackIndex or index
+				break
+			end
+		end
+	end
+	return fallbackIndex
+end
+
 local function snapshotSocketGroupReimportState(socketGroup, isMainGroup)
 	local gemStates = { }
 	for gemIndex, gem in ipairs(socketGroup.gemList) do
@@ -1390,7 +1406,18 @@ function ImportTabClass:ImportItemsAndSkills(charData, clearItems, clearSkills,
 	local mainSkillEmpty = #self.build.skillsTab.socketGroupList == 0
 	local skillOrder
 	local preservedSocketGroupStateByKey
+	local preservedMainSkillId
+	local preservedMainGroupSlot
+	local preservedMainGrantedEffectId
 	if clearSkills then
+		local mainSocketGroup = self.build.skillsTab.socketGroupList[self.build.mainSocketGroup]
+		local mainActiveSkill = mainSocketGroup and mainSocketGroup.displaySkillList
+			and mainSocketGroup.displaySkillList[mainSocketGroup.mainActiveSkill or 1]
+		local mainActiveEffect = mainActiveSkill and mainActiveSkill.activeEffect
+		local srcInstance = mainActiveEffect and mainActiveEffect.srcInstance
+		preservedMainSkillId = srcInstance and srcInstance.skillId
+		preservedMainGroupSlot = mainSocketGroup and mainSocketGroup.slot
+		preservedMainGrantedEffectId = mainActiveEffect and mainActiveEffect.grantedEffect and mainActiveEffect.grantedEffect.id
 		skillOrder = { }
 		preservedSocketGroupStateByKey = { }
 		for _, socketGroup in ipairs(self.build.skillsTab.socketGroupList) do
@@ -1472,6 +1499,15 @@ function ImportTabClass:ImportItemsAndSkills(charData, clearItems, clearSkills,
 		end
 		if restoredMainSocketGroup then
 			self.build.mainSocketGroup = restoredMainSocketGroup
+		elseif not mainSkillEmpty then
+			local matchingMainSocketGroup = preservedMainSkillId
+				and findSocketGroupBySkillId(self.build.skillsTab.socketGroupList, preservedMainSkillId, preservedMainGroupSlot)
+			if matchingMainSocketGroup then
+				self.build.mainSocketGroup = matchingMainSocketGroup
+				self.build.skillsTab.socketGroupList[matchingMainSocketGroup].pendingMainGrantedEffectId = preservedMainGrantedEffectId
+			else
+				self.build.mainSocketGroup = self:GuessMainSocketGroup()
+			end
 		end
 	end
 	if mainSkillEmpty then

src/Modules/CalcSetup.lua

@@ -1773,6 +1773,17 @@ function calcs.initEnv(build, mode, override, specEnv)
 					env.player.modDB:AddMod(modLib.setSource(value.value, groupCfg.slotName or ""))
 				end
 
+				-- Reimport can defer a support-granted selection until this MAIN skill list exists.
+				-- Consume it once, then clear it below.
+				if index == env.mainSocketGroup and env.mode == "MAIN" and group.pendingMainGrantedEffectId then
+					for activeSkillIndex, activeSkill in ipairs(socketGroupSkillList) do
+						if activeSkill.activeEffect.grantedEffect.id == group.pendingMainGrantedEffectId then
+							group.mainActiveSkill = activeSkillIndex
+							break
+						end
+					end
+				end
+
 				if index == env.mainSocketGroup and #socketGroupSkillList > 0 then
 					-- Select the main skill from this socket group
 					local activeSkillIndex
@@ -1790,6 +1801,7 @@ function calcs.initEnv(build, mode, override, specEnv)
 			end
 
 			if env.mode == "MAIN" then
+				group.pendingMainGrantedEffectId = nil
 				-- Create display label for the socket group if the user didn't specify one
 				if group.label and group.label:match("%S") then
 					group.displayLabel = group.label