# CoA client bug — GameTooltipMods.lua nil `lineText` in ModTooltipSetSpell

**Component:** CoA/Ascension client FrameXML mod (shipped in `Data/patch-B.MPQ` →
`Interface\FrameXML\GameTooltipMods.lua`). NOT an addon — this is the client.

**Realm seen:** Vol'jin — CoA Beta. Reproduces on a custom-class character (e.g.
Guardian) by **hovering a MultiCast totem / standard action button** with any
tooltip-embedding addon active (TradeSkillMaster's LibExtraTip in our case, but
any addon that re-fires the tooltip triggers it).

## Error

```
Interface\FrameXML\GameTooltipMods.lua:109: attempt to index local 'lineText' (a nil value)
  GameTooltipMods.lua:109: in function `func'
  GameTooltip.lua:361 ... LibExtraTip ... SetAction
  ActionButton.lua:514 ActionButton_SetTooltip
  MultiCastActionBarFrame.lua:462 MultiCastActionButton_OnEnter
spellName = "Standard of Recovery", spellID = 500260, line index i = 4
```

## Cause

`ModTooltipSetSpell:EmbedSpell` (and the custom-class totem block lower in the
file) call `left:GetText()` and immediately index the result with no nil guard:

```lua
function ModTooltipSetSpell:EmbedSpell(left, right, spellID)
    local lineText = left:GetText()
    if lineText:find("%b@@") then          -- line 109: lineText can be nil
```

`GameTooltipTextLeftN` regions exist but return `nil` from `GetText()` when the
line is empty (common on multi-line spell tooltips like totem/standard buttons —
here line 4 is blank). The sibling `ModTooltipSetItem:DoCustomFormatters` in the
**same file** already guards correctly:

```lua
function ModTooltipSetItem:DoCustomFormatters(left)
    if not left:GetFont() or not left:GetText() or not left:GetText():find("%b@@") then return end
```

`ModTooltipSetSpell:EmbedSpell` just needs the same guard.

## Fix (one line each)

`ModTooltipSetSpell:EmbedSpell` — add at the top of the function:

```lua
function ModTooltipSetSpell:EmbedSpell(left, right, spellID)
    local lineText = left:GetText()
    if not lineText then return end        -- <-- add
    if lineText:find("%b@@") then
        ...
```

And the custom-class totem block lower down (the second
`local lineText = left:GetText()` followed by `lineText:startswith(SPELL_TOTEMS)`)
needs the same `if not lineText then return end` / `if lineText and ...` guard —
it has the identical latent nil-deref.

No addon-side fix is possible; the crash is in client FrameXML. Reported by
Sub-Net (Exiles guild) from the coa-* addon-porting work.