save sync update

docs/new-features.md

@@ -14,6 +14,7 @@ Features intentionally added beyond the original Pokémon Red, Blue, and Yellow
 * **Screen position setting** (center, upper, top) shared across all games, for clamp-on controllers that cover the lower screen
 * **Touch skins** in RetroArch overlay format and Delta `.deltaskin` (including PDF-wrapped bezel art), with per-button press states and Super Game Boy borders
 * **Pokédex diploma and printer image exports**
+* **Shareable mod lists** over save sync, optionally carrying the options set for those mods, which the receiving device is asked about before anything is changed
 
 ## Gen 2 Specifics
 

src/import/LauncherView.lua

@@ -4362,21 +4362,70 @@ local function syncTitle(imp, m, px, py, pw, pad)
   return py + Kit.textHeight("button") + math.floor(12 * m.s)
 end
 
-local function syncStatus(imp, m, x, y, w, eng)
+local function syncWidth(m, want)
+  return math.floor(math.min(want, m.W - 2 * m.pad))
+end
+
+local function syncFit(m, fixed, rows, gaps, texts)
+  local fit = { btnH = m.btnH, gap = math.floor(8 * m.s), lines = {} }
+  local avail = m.H - 2 * m.pad
+  texts = texts or {}
+  for i, blk in ipairs(texts) do fit.lines[i] = blk.max end
+  local function total()
+    local t = fixed + rows * fit.btnH + gaps * fit.gap
+    for i, blk in ipairs(texts) do
+      t = t + Kit.wrapHeight(blk.font, blk.str, blk.w, fit.lines[i])
+    end
+    return t
+  end
+  while total() > avail do
+    local worst, worstH = nil, 0
+    for i, blk in ipairs(texts) do
+      if fit.lines[i] > 1 then
+        local hgt = Kit.wrapHeight(blk.font, blk.str, blk.w, fit.lines[i])
+        if hgt > worstH then worst, worstH = i, hgt end
+      end
+    end
+    if not worst then break end
+    fit.lines[worst] = fit.lines[worst] - 1
+  end
+  if total() > avail and gaps > 0 then
+    fit.gap = math.max(math.max(2, math.floor(3 * m.s)),
+      fit.gap - math.ceil((total() - avail) / gaps))
+  end
+  if total() > avail and rows > 0 then
+    fit.btnH = math.max(Kit.tapMin(),
+      fit.btnH - math.ceil((total() - avail) / rows))
+  end
+  fit.over = total() - avail
+  fit.h = math.min(total(), avail)
+  return fit
+end
+
+local function syncStatus(imp, m, x, y, w, eng, fit)
+  local bh = (fit and fit.btnH) or m.btnH
+  local gap = (fit and fit.gap) or math.floor(8 * m.s)
   if eng:busy() then
-    Loader.inline(x, y, w, m.btnH, eng.status)
-    return m.btnH + math.floor(8 * m.s)
+    Loader.inline(x, y, w, bh, eng.status)
+    return bh + gap
   end
   Kit.text("small", Kit.ellipsize("small", eng.status or "", w), x, y,
     eng.phase == "error" and PAL.red or PAL.muted)
+  return Kit.textHeight("small") + gap + math.floor(2 * m.s)
+end
+
+local function syncReserve(m, eng)
+  if eng:busy() then return m.btnH + math.floor(8 * m.s) end
   return Kit.textHeight("small") + math.floor(10 * m.s)
 end
 
-local function syncRow(imp, m, x, y, w, key, label, opts)
+local function syncRow(imp, m, x, y, w, key, label, opts, fit)
   opts = opts or {}
   opts.font = "small"
-  btn(imp, x, y, w, m.btnH, key, label, opts)
-  return y + m.btnH + math.floor(8 * m.s)
+  local bh = (fit and fit.btnH) or m.btnH
+  local gap = (fit and fit.gap) or math.floor(8 * m.s)
+  btn(imp, x, y, w, bh, key, label, opts)
+  return y + bh + gap
 end
 
 function LauncherView.syncSideText(meta)
@@ -4408,91 +4457,99 @@ end
 local function buildSyncConflict(imp, m, eng)
   local row = eng.conflicts[1]
   local pad = math.floor(18 * m.s)
-  local w = math.floor(520 * m.s)
+  local w = syncWidth(m, math.floor(520 * m.s))
   local innerW = w - 2 * pad
   local lead = row.overlap
     and Strings("These saves were played at the same time.")
     or Strings("This save also changed on another device.")
-  local leadH = Kit.wrapHeight("small", lead, innerW, 2)
-  local sideH = Kit.textHeight("small") + math.floor(2 * m.s)
-    + Kit.wrapHeight("micro", "x", innerW, 2)
-  local h = pad + Kit.textHeight("button") + math.floor(12 * m.s) + leadH
-    + math.floor(10 * m.s) + 2 * (sideH + math.floor(10 * m.s))
-    + 4 * (m.btnH + math.floor(8 * m.s)) + pad
-  local px, py, pw = modalPanel(m, w, h)
+  local mine = LauncherView.syncSideText(row.localMeta)
+  local theirs = LauncherView.syncSideText(row.remoteMeta)
+  local fit = syncFit(m,
+    2 * pad + Kit.textHeight("button") + math.floor(22 * m.s)
+      + 2 * (Kit.textHeight("small") + math.floor(12 * m.s)),
+    4, 4, {
+      { font = "small", str = lead, w = innerW, max = 2 },
+      { font = "micro", str = mine, w = innerW, max = 2 },
+      { font = "micro", str = theirs, w = innerW, max = 2 },
+    })
+  local px, py, pw = modalPanel(m, w, fit.h)
   local cy = syncTitle(imp, m, px, py + pad, pw, pad)
-  cy = cy + Kit.textWrapped("small", lead, px + pad, cy, pw - 2 * pad,
-    PAL.detail, 2) + math.floor(10 * m.s)
+  cy = cy + Kit.textWrapped("small", lead, px + pad, cy, innerW,
+    PAL.detail, fit.lines[1]) + math.floor(10 * m.s)
 
-  local function side(title, meta)
+  local function side(title, text, lines)
     Kit.text("small", title, px + pad, cy, PAL.heading)
     cy = cy + Kit.textHeight("small") + math.floor(2 * m.s)
-    cy = cy + Kit.textWrapped("micro", LauncherView.syncSideText(meta),
-      px + pad, cy, pw - 2 * pad, PAL.muted, 2) + math.floor(10 * m.s)
+    cy = cy + Kit.textWrapped("micro", text, px + pad, cy, innerW,
+      PAL.muted, lines) + math.floor(10 * m.s)
   end
   side(Strings("This device") .. "  \194\183  " .. tostring(row.version or "?"),
-    row.localMeta)
-  side(Strings("Other device"), row.remoteMeta)
+    mine, fit.lines[2])
+  side(Strings("Other device"), theirs, fit.lines[3])
 
   local key = row.key
-  cy = syncRow(imp, m, px + pad, cy, pw - 2 * pad, "sync-keep-this",
+  cy = syncRow(imp, m, px + pad, cy, innerW, "sync-keep-this",
     Strings("Keep this device"), { kind = "primary",
-      action = function() imp:_syncResolve(key, "local") end })
-  cy = syncRow(imp, m, px + pad, cy, pw - 2 * pad, "sync-keep-other",
+      action = function() imp:_syncResolve(key, "local") end }, fit)
+  cy = syncRow(imp, m, px + pad, cy, innerW, "sync-keep-other",
     Strings("Keep the other device"), { kind = "accent",
-      action = function() imp:_syncResolve(key, "remote") end })
-  cy = syncRow(imp, m, px + pad, cy, pw - 2 * pad, "sync-keep-both",
+      action = function() imp:_syncResolve(key, "remote") end }, fit)
+  cy = syncRow(imp, m, px + pad, cy, innerW, "sync-keep-both",
     Strings("Keep both"), {
-      action = function() imp:_syncResolve(key, "both") end })
-  syncRow(imp, m, px + pad, cy, pw - 2 * pad, "sync-conflict-close",
-    Strings("Close"), { action = function() imp:_closeSync() end })
+      action = function() imp:_syncResolve(key, "both") end }, fit)
+  syncRow(imp, m, px + pad, cy, innerW, "sync-conflict-close",
+    Strings("Close"), { action = function() imp:_closeSync() end }, fit)
 end
 
 local function buildSyncLink(imp, m, eng)
   local mo = imp._syncModal
   local pad = math.floor(18 * m.s)
-  local w = math.floor(460 * m.s)
-  local fieldH = math.max(Kit.tapMin(), math.floor(36 * m.s))
+  local w = syncWidth(m, math.floor(460 * m.s))
+  local innerW = w - 2 * pad
   local hint = Strings("Enter the two codes the other device is showing.")
-  local hintH = Kit.wrapHeight("small", hint, w - 2 * pad, 2)
-  local h = pad + Kit.textHeight("button") + math.floor(12 * m.s) + hintH
-    + math.floor(10 * m.s) + 2 * (fieldH + math.floor(8 * m.s))
-    + Kit.textHeight("small") + math.floor(10 * m.s)
-    + 2 * (m.btnH + math.floor(8 * m.s)) + pad
-  local px, py, pw = modalPanel(m, w, h)
+  local fieldH = math.max(Kit.tapMin(), math.floor(36 * m.s))
+  local fit = syncFit(m,
+    2 * pad + Kit.textHeight("button") + math.floor(22 * m.s)
+      + 2 * (fieldH + math.floor(8 * m.s)) + syncReserve(m, eng),
+    2, 2, { { font = "small", str = hint, w = innerW, max = 2 } })
+  local px, py, pw = modalPanel(m, w, fit.h)
   local cy = syncTitle(imp, m, px, py + pad, pw, pad)
-  cy = cy + Kit.textWrapped("small", hint, px + pad, cy, pw - 2 * pad,
-    PAL.detail, 2) + math.floor(10 * m.s)
-  textField(imp, px + pad, cy, pw - 2 * pad, fieldH, "sync-code1",
+  cy = cy + Kit.textWrapped("small", hint, px + pad, cy, innerW,
+    PAL.detail, fit.lines[1]) + math.floor(10 * m.s)
+  textField(imp, px + pad, cy, innerW, fieldH, "sync-code1",
     mo.code1 or "", Strings("First code"), imp._syncFocus == "code1",
     function() imp:_syncFocusField("code1") end)
-  cy = cy + fieldH + math.floor(8 * m.s)
-  textField(imp, px + pad, cy, pw - 2 * pad, fieldH, "sync-code2",
+  cy = cy + fieldH + fit.gap
+  textField(imp, px + pad, cy, innerW, fieldH, "sync-code2",
     mo.code2 or "", Strings("Second code"), imp._syncFocus == "code2",
     function() imp:_syncFocusField("code2") end)
-  cy = cy + fieldH + math.floor(8 * m.s)
-  cy = cy + syncStatus(imp, m, px + pad, cy, pw - 2 * pad, eng)
-  cy = syncRow(imp, m, px + pad, cy, pw - 2 * pad, "sync-link-go",
+  cy = cy + fieldH + fit.gap
+  cy = cy + syncStatus(imp, m, px + pad, cy, innerW, eng, fit)
+  cy = syncRow(imp, m, px + pad, cy, innerW, "sync-link-go",
     Strings("Link this device"), { kind = "primary", enabled = not eng:busy(),
-      action = function() imp:_syncLink() end })
-  syncRow(imp, m, px + pad, cy, pw - 2 * pad, "sync-link-back",
-    Strings("Back"), { action = function() imp:_syncView("home") end })
+      action = function() imp:_syncLink() end }, fit)
+  syncRow(imp, m, px + pad, cy, innerW, "sync-link-back",
+    Strings("Back"), { action = function() imp:_syncView("home") end }, fit)
 end
 
 local function buildSyncMods(imp, m, eng)
   local mo = imp._syncModal
   local pad = math.floor(18 * m.s)
-  local w = math.floor(500 * m.s)
+  local w = syncWidth(m, math.floor(500 * m.s))
+  local innerW = w - 2 * pad
   local fieldH = math.max(Kit.tapMin(), math.floor(36 * m.s))
   local plan = eng.modPlan
   local rows = 4 + (plan and 1 or 0)
-  local h = pad + Kit.textHeight("button") + math.floor(12 * m.s)
-    + 3 * (Kit.textHeight("small") + math.floor(8 * m.s))
-    + fieldH + math.floor(8 * m.s)
-    + rows * (m.btnH + math.floor(8 * m.s)) + pad
-  local px, py, pw = modalPanel(m, w, h)
+  local codeH = eng.shareCode and (Kit.textHeight("small")
+    + Kit.textHeight("stat") + Kit.textHeight("micro")
+    + math.floor(18 * m.s)) or 0
+  local planH = plan and (Kit.textHeight("small") + math.floor(8 * m.s)) or 0
+  local fit = syncFit(m,
+    2 * pad + Kit.textHeight("button") + math.floor(12 * m.s) + codeH + planH
+      + fieldH + math.floor(8 * m.s) + syncReserve(m, eng),
+    rows, rows, {})
+  local px, py, pw = modalPanel(m, w, fit.h)
   local cy = syncTitle(imp, m, px, py + pad, pw, pad)
-  local innerW = pw - 2 * pad
 
   if eng.shareCode then
     Kit.text("small", Strings("Share this code:"), px + pad, cy, PAL.muted)
@@ -4504,17 +4561,23 @@ local function buildSyncMods(imp, m, eng)
       px + pad, cy, PAL.muted)
     cy = cy + Kit.textHeight("micro") + math.floor(10 * m.s)
   end
+  local withOptions = mo.withOptions ~= false
+  cy = syncRow(imp, m, px + pad, cy, innerW, "sync-share-options",
+    Strings("Include my mod options") .. "  \194\183  "
+      .. (withOptions and Strings("ON") or Strings("OFF")),
+    { kind = withOptions and "accent" or nil, enabled = not eng:busy(),
+      action = function() imp:_syncToggleShareOptions() end }, fit)
   cy = syncRow(imp, m, px + pad, cy, innerW, "sync-share-mods",
     Strings("Share mod list"), { kind = "accent", enabled = not eng:busy(),
-      action = function() imp:_syncShareMods() end })
+      action = function() imp:_syncShareMods() end }, fit)
 
   textField(imp, px + pad, cy, innerW, fieldH, "sync-share-code",
     mo.share or "", Strings("Paste a 6-character mod code"),
     imp._syncFocus == "share", function() imp:_syncFocusField("share") end)
-  cy = cy + fieldH + math.floor(8 * m.s)
+  cy = cy + fieldH + fit.gap
   cy = syncRow(imp, m, px + pad, cy, innerW, "sync-get-mods",
     Strings("Get mod list"), { kind = "accent", enabled = not eng:busy(),
-      action = function() imp:_syncGetShare() end })
+      action = function() imp:_syncGetShare() end }, fit)
 
   if plan then
     local line = Strings("%d mods, %d indexes to add",
@@ -4523,24 +4586,29 @@ local function buildSyncMods(imp, m, eng)
       line = line .. "  \194\183  " .. Strings("%d not in your indexes",
         #plan.missing)
     end
+    if #(plan.options or {}) > 0 then
+      line = line .. "  \194\183  " .. (plan.applyOptions
+        and Strings("options for %d mods", #plan.options)
+        or Strings("their options skipped"))
+    end
     Kit.text("small", Kit.ellipsize("small", line, innerW), px + pad, cy,
       PAL.detail)
     cy = cy + Kit.textHeight("small") + math.floor(8 * m.s)
     local prog = mo.progress
     if prog then
-      Loader.inline(px + pad, cy, innerW, m.btnH,
+      Loader.inline(px + pad, cy, innerW, fit.btnH,
         Strings("%d of %d", prog.done or 0, prog.total or 0))
-      cy = cy + m.btnH + math.floor(8 * m.s)
+      cy = cy + fit.btnH + fit.gap
     else
       cy = syncRow(imp, m, px + pad, cy, innerW, "sync-apply-mods",
         Strings("Apply these mods"), { kind = "primary",
           enabled = not eng:busy(),
-          action = function() imp:_syncApplyMods() end })
+          action = function() imp:_syncApplyMods() end }, fit)
     end
   end
-  cy = cy + syncStatus(imp, m, px + pad, cy, innerW, eng)
+  cy = cy + syncStatus(imp, m, px + pad, cy, innerW, eng, fit)
   syncRow(imp, m, px + pad, cy, innerW, "sync-mods-back", Strings("Back"),
-    { action = function() imp:_syncView("home") end })
+    { action = function() imp:_syncView("home") end }, fit)
 end
 
 function LauncherView.syncDeviceRows(eng, limit)
@@ -4562,29 +4630,35 @@ end
 
 local function buildSyncHome(imp, m, eng)
   local pad = math.floor(18 * m.s)
-  local w = math.floor(460 * m.s)
+  local w = syncWidth(m, math.floor(460 * m.s))
   local linked = eng:linked()
   local codes = eng.codes
   local body = linked
     and Strings("This device is linked. Saves sync when the launcher opens, a few seconds after each save, and every few minutes while the app is running.")
     or Strings(SYNC_HINT)
   local innerW = w - 2 * pad
-  local hintH = Kit.wrapHeight("small", body, innerW, 5)
   local codesH = codes
     and (Kit.textHeight("small") + math.floor(6 * m.s)
       + 2 * (Kit.textHeight("title") + math.floor(4 * m.s))
       + math.floor(8 * m.s)) or 0
   local devices = linked and LauncherView.syncDeviceRows(eng) or {}
-  local devicesH = #devices > 0
-    and (Kit.textHeight("small") + math.floor(6 * m.s)) or 0
-  local rows = (linked and 5 or 3) + #devices
-  local h = pad + Kit.textHeight("button") + math.floor(12 * m.s) + hintH
-    + math.floor(10 * m.s) + codesH + devicesH + m.btnH + math.floor(10 * m.s)
-    + rows * (m.btnH + math.floor(8 * m.s)) + pad
-  local px, py, pw = modalPanel(m, w, h)
+  local hidden, fit = 0, nil
+  repeat
+    local devicesH = #devices > 0
+      and (Kit.textHeight("small") + math.floor(6 * m.s)) or 0
+    fit = syncFit(m,
+      2 * pad + Kit.textHeight("button") + math.floor(22 * m.s) + codesH
+        + devicesH + syncReserve(m, eng),
+      (linked and 4 or 3) + #devices, (linked and 4 or 3) + #devices,
+      { { font = "small", str = body, w = innerW, max = 5 } })
+    if fit.over <= 0 or #devices == 0 then break end
+    table.remove(devices)
+    hidden = hidden + 1
+  until false
+  local px, py, pw = modalPanel(m, w, fit.h)
   local cy = syncTitle(imp, m, px, py + pad, pw, pad)
-  cy = cy + Kit.textWrapped("small", body, px + pad, cy, innerW, PAL.detail, 5)
-    + math.floor(10 * m.s)
+  cy = cy + Kit.textWrapped("small", body, px + pad, cy, innerW, PAL.detail,
+    fit.lines[1]) + math.floor(10 * m.s)
 
   if codes then
     Kit.text("small", Strings("Enter these on your other device:"), px + pad,
@@ -4595,23 +4669,24 @@ local function buildSyncHome(imp, m, eng)
     Kit.text("title", codes.code2, px + pad, cy, PAL.heading)
     cy = cy + Kit.textHeight("title") + math.floor(8 * m.s)
   end
-  cy = cy + syncStatus(imp, m, px + pad, cy, innerW, eng)
+  cy = cy + syncStatus(imp, m, px + pad, cy, innerW, eng, fit)
 
   if #devices > 0 then
-    Kit.text("small", Strings("Devices on this account:"), px + pad, cy,
-      PAL.muted)
+    Kit.text("small", hidden > 0
+      and Strings("Devices on this account (%d more)", hidden)
+      or Strings("Devices on this account:"), px + pad, cy, PAL.muted)
     cy = cy + Kit.textHeight("small") + math.floor(6 * m.s)
     for i, device in ipairs(devices) do
       local id = device.id
       if device.current then
         cy = syncRow(imp, m, px + pad, cy, innerW, "sync-device-" .. i,
           device.label .. "  \194\183  " .. Strings("this device"),
-          { enabled = false })
+          { enabled = false }, fit)
       else
         cy = syncRow(imp, m, px + pad, cy, innerW, "sync-device-" .. i,
           Strings("Unlink %s", device.label), { kind = "danger",
             enabled = not eng:busy(),
-            action = function() imp:_syncUnlinkDevice(id) end })
+            action = function() imp:_syncUnlinkDevice(id) end }, fit)
       end
     end
   end
@@ -4619,38 +4694,69 @@ local function buildSyncHome(imp, m, eng)
   if linked then
     cy = syncRow(imp, m, px + pad, cy, innerW, "sync-now", Strings("Sync now"),
       { kind = "primary", enabled = not eng:busy(),
-        action = function() imp:_syncNow() end })
+        action = function() imp:_syncNow() end }, fit)
     cy = syncRow(imp, m, px + pad, cy, innerW, "sync-mods",
       Strings("Share or get a mod list"), { kind = "accent",
-        action = function() imp:_syncView("mods") end })
+        action = function() imp:_syncView("mods") end }, fit)
     cy = syncRow(imp, m, px + pad, cy, innerW, "sync-unlink",
       Strings("Unlink this device"), { kind = "danger",
-        action = function() imp:_syncUnlink() end })
+        action = function() imp:_syncUnlink() end }, fit)
   else
     cy = syncRow(imp, m, px + pad, cy, innerW, "sync-create",
       Strings("Create sync account"), { kind = "primary",
         enabled = not eng:busy(),
-        action = function() imp:_syncCreate() end })
+        action = function() imp:_syncCreate() end }, fit)
     cy = syncRow(imp, m, px + pad, cy, innerW, "sync-link",
       Strings("Link this device"), { kind = "accent",
-        action = function() imp:_syncView("link") end })
+        action = function() imp:_syncView("link") end }, fit)
   end
   syncRow(imp, m, px + pad, cy, innerW, "sync-close", Strings("Close"),
-    { action = function() imp:_closeSync() end })
+    { action = function() imp:_closeSync() end }, fit)
+end
+
+local function buildSyncModOptions(imp, m, eng)
+  local plan = eng.modPlan
+  local ids = {}
+  for _, row in ipairs(plan.options or {}) do ids[#ids + 1] = row.id end
+  local pad = math.floor(18 * m.s)
+  local w = syncWidth(m, math.floor(480 * m.s))
+  local innerW = w - 2 * pad
+  local lead = Strings(
+    "This mod list also carries the options its owner set for %d mods. Import their options, or keep the ones you have?",
+    #ids)
+  local names = table.concat(ids, ", ")
+  local fit = syncFit(m,
+    2 * pad + Kit.textHeight("button") + math.floor(32 * m.s), 2, 2, {
+      { font = "small", str = lead, w = innerW, max = 4 },
+      { font = "micro", str = names, w = innerW, max = 3 },
+    })
+  local px, py, pw = modalPanel(m, w, fit.h)
+  local cy = syncTitle(imp, m, px, py + pad, pw, pad)
+  cy = cy + Kit.textWrapped("small", lead, px + pad, cy, innerW, PAL.detail,
+    fit.lines[1]) + math.floor(8 * m.s)
+  cy = cy + Kit.textWrapped("micro", names, px + pad, cy, innerW, PAL.muted,
+    fit.lines[2]) + math.floor(12 * m.s)
+  cy = syncRow(imp, m, px + pad, cy, innerW, "sync-options-import",
+    Strings("Import their options"), { kind = "primary",
+      action = function() imp:_syncAnswerModOptions(true) end }, fit)
+  syncRow(imp, m, px + pad, cy, innerW, "sync-options-skip",
+    Strings("Keep my options"), {
+      action = function() imp:_syncAnswerModOptions(false) end }, fit)
 end
 
 local function buildSyncUnavailable(imp, m, msg)
   local pad = math.floor(18 * m.s)
-  local w = math.floor(420 * m.s)
-  local h = pad + Kit.textHeight("button") + math.floor(12 * m.s)
-    + Kit.wrapHeight("small", msg, w - 2 * pad, 4) + math.floor(10 * m.s)
-    + m.btnH + pad
-  local px, py, pw = modalPanel(m, w, h)
+  local w = syncWidth(m, math.floor(420 * m.s))
+  local innerW = w - 2 * pad
+  local fit = syncFit(m,
+    2 * pad + Kit.textHeight("button") + math.floor(22 * m.s), 1, 0,
+    { { font = "small", str = msg, w = innerW, max = 4 } })
+  local px, py, pw = modalPanel(m, w, fit.h)
   local cy = syncTitle(imp, m, px, py + pad, pw, pad)
-  cy = cy + Kit.textWrapped("small", msg, px + pad, cy, pw - 2 * pad,
-    PAL.detail, 4) + math.floor(10 * m.s)
-  syncRow(imp, m, px + pad, cy, pw - 2 * pad, "sync-close",
-    Strings("Close"), { action = function() imp:_closeSync() end })
+  cy = cy + Kit.textWrapped("small", msg, px + pad, cy, innerW,
+    PAL.detail, fit.lines[1]) + math.floor(10 * m.s)
+  syncRow(imp, m, px + pad, cy, innerW, "sync-close",
+    Strings("Close"), { action = function() imp:_closeSync() end }, fit)
 end
 
 local function buildSyncModal(imp, m)
@@ -4669,6 +4775,12 @@ local function buildSyncModal(imp, m)
     buildSyncConflict(imp, m, eng)
     return
   end
+  local plan = eng.modPlan
+  if type(plan) == "table" and #(plan.options or {}) > 0
+      and plan.applyOptions == nil then
+    buildSyncModOptions(imp, m, eng)
+    return
+  end
   local view = imp._syncModal and imp._syncModal.view or "home"
   if view == "link" then
     buildSyncLink(imp, m, eng)

src/import/RomImporter.lua

@@ -3478,7 +3478,7 @@ end
 function RomImporter:_openSync()
   self:_syncEngine()
   self._syncModal = self._syncModal
-    or { view = "home", code1 = "", code2 = "", share = "" }
+    or { view = "home", code1 = "", code2 = "", share = "", withOptions = true }
   self._syncFocus = nil
   self:_disarmTextInput()
 end
@@ -3563,9 +3563,22 @@ function RomImporter:_syncUnlinkDevice(deviceId)
 end
 
 function RomImporter:_syncShareMods()
-  local eng = self:_syncEngine()
+  local eng, mo = self:_syncEngine(), self._syncModal
   if not eng then return false end
-  return eng:shareMods()
+  return eng:shareMods(mo and mo.withOptions ~= false)
+end
+
+function RomImporter:_syncToggleShareOptions()
+  local mo = self._syncModal
+  if not mo then return false end
+  mo.withOptions = not (mo.withOptions ~= false)
+  return mo.withOptions
+end
+
+function RomImporter:_syncAnswerModOptions(importThem)
+  local eng = self:_syncEngine()
+  if not eng or type(eng.answerModOptions) ~= "function" then return false end
+  return eng:answerModOptions(importThem)
 end
 
 function RomImporter:_syncGetShare()

src/mods/LauncherMods.lua

@@ -603,6 +603,33 @@ function LauncherMods.setEnabled(id, enabled, version)
   return true
 end
 
+function LauncherMods.modOptions()
+  local ok, options = pcall(SaveData.loadOptions)
+  if not ok or type(options) ~= "table" then return {} end
+  return options.modOptions or {}
+end
+
+function LauncherMods.setModOptions(id, values)
+  if type(id) ~= "string" or id == "" or type(values) ~= "table" then
+    return false
+  end
+  local options = SaveData.loadOptions()
+  if SaveData.isSafeMode(options) then return false end
+  options.modOptions = options.modOptions or {}
+  local bucket = options.modOptions[id] or {}
+  for key, value in pairs(values) do
+    local t = type(value)
+    if type(key) == "string" and key ~= ""
+        and (t == "string" or t == "number" or t == "boolean") then
+      bucket[key] = value
+    end
+  end
+  options.modOptions[id] = bucket
+  SaveData.saveOptions(options)
+  LauncherMods.syncActiveProfile(options)
+  return true
+end
+
 -- setAllEnabled(ids, enabled [, version]): the launcher's Enable all / Disable
 -- all buttons (#647).  Writes what setEnabled writes, but loads and
 -- saves once for the whole list: saveOptions rewrites the whole options file per

src/sync/SyncEngine.lua

@@ -596,12 +596,13 @@ function SyncEngine:resolveConflict(key, choice)
   return true
 end
 
-function SyncEngine:uploadMods()
+function SyncEngine:uploadMods(includeOptions)
   if not self:linked() then return false, "this device is not linked" end
   if self:busy() then return false, "sync is busy" end
-  local manifest = SyncMods.build(self.modDeps)
+  local manifest = SyncMods.build(self.modDeps, includeOptions)
   self.phase = "uploading"
-  self.status = "Uploading the mod list..."
+  self.status = includeOptions and "Uploading the mod list and options..."
+    or "Uploading the mod list..."
   local handle, err = self.client:putMods(manifest)
   return self:_request(handle, err, function(eng)
     eng.phase = "idle"
@@ -618,19 +619,17 @@ function SyncEngine:fetchModPlan()
   return self:_request(handle, err, function(eng, res)
     local data = res.data or {}
     local manifest = type(data.manifest) == "table" and data.manifest or data
-    eng.modPlan = SyncMods.plan(manifest, eng.modDeps)
-    eng.phase = "idle"
-    eng.status = SyncMods.planEmpty(eng.modPlan)
-      and "Mods already match" or "Mod changes ready to apply"
+    eng:_takeModPlan(SyncMods.plan(manifest, eng.modDeps))
   end)
 end
 
-function SyncEngine:shareMods()
+function SyncEngine:shareMods(includeOptions)
   if not self:linked() then return false, "this device is not linked" end
   if self:busy() then return false, "sync is busy" end
-  local manifest = SyncMods.build(self.modDeps)
+  local manifest = SyncMods.build(self.modDeps, includeOptions)
   self.phase = "uploading"
-  self.status = "Sharing the mod list..."
+  self.status = includeOptions and "Sharing the mod list and options..."
+    or "Sharing the mod list..."
   local handle, err = self.client:shareMods(manifest)
   return self:_request(handle, err, function(eng, res)
     local data = res.data or {}
@@ -649,16 +648,44 @@ function SyncEngine:fetchShare(code)
   return self:_request(handle, err, function(eng, res)
     local data = res.data or {}
     local manifest = type(data.manifest) == "table" and data.manifest or data
-    eng.modPlan = SyncMods.plan(manifest, eng.modDeps)
-    eng.phase = "idle"
-    eng.status = SyncMods.planEmpty(eng.modPlan)
-      and "Mods already match" or "Mod changes ready to apply"
+    eng:_takeModPlan(SyncMods.plan(manifest, eng.modDeps))
   end)
 end
 
+function SyncEngine:_takeModPlan(plan)
+  self.modPlan = plan
+  self.phase = "idle"
+  if SyncMods.planHasOptions(plan) then
+    self.status = ("This list carries options for %d mods.")
+      :format(#plan.options)
+  elseif SyncMods.planEmpty(plan) then
+    self.status = "Mods already match"
+  else
+    self.status = "Mod changes ready to apply"
+  end
+end
+
+function SyncEngine:modOptionsAsk()
+  local plan = self.modPlan
+  if not SyncMods.planHasOptions(plan) then return nil end
+  if plan.applyOptions ~= nil then return nil end
+  return SyncMods.optionModIds(plan)
+end
+
+function SyncEngine:answerModOptions(importThem)
+  local plan = self.modPlan
+  if not SyncMods.planHasOptions(plan) then return false end
+  SyncMods.answerOptions(plan, importThem)
+  self.status = plan.applyOptions
+    and "Their mod options will be imported too"
+    or "Their mod options will be skipped"
+  return plan.applyOptions
+end
+
 function SyncEngine:applyModPlan(progress)
   if not self.modPlan then return false, "no mod plan" end
   if self.modApply then return false, "the mods are already being applied" end
+  self.modPlan.applyOptions = self.modPlan.applyOptions == true
   local steps = SyncMods.steps(self.modPlan, self.modDeps)
   if #steps == 0 then
     self.modPlan = nil

src/sync/SyncMods.lua

@@ -1,6 +1,8 @@
 local SyncMods = {}
 
-SyncMods.REV = 1
+SyncMods.REV = 2
+SyncMods.MAX_OPTION_KEYS = 64
+SyncMods.MAX_OPTION_TEXT = 256
 
 local function versions()
   local ok, GameVersion = pcall(require, "src.core.GameVersion")
@@ -35,6 +37,12 @@ local function defaultDeps()
     setEnabled = function(id, enabled, version)
       return require("src.mods.LauncherMods").setEnabled(id, enabled, version)
     end,
+    modOptions = function()
+      return require("src.mods.LauncherMods").modOptions()
+    end,
+    setOptions = function(id, values)
+      return require("src.mods.LauncherMods").setModOptions(id, values)
+    end,
   }
 end
 
@@ -46,6 +54,41 @@ local function deps(given)
   return out
 end
 
+local function sanitizeOptions(bucket)
+  if type(bucket) ~= "table" then return nil end
+  local keys = {}
+  for k, v in pairs(bucket) do
+    local t = type(v)
+    if type(k) == "string" and k ~= ""
+        and (t == "string" or t == "number" or t == "boolean") then
+      keys[#keys + 1] = k
+    end
+  end
+  if #keys == 0 then return nil end
+  table.sort(keys)
+  local out, n = {}, 0
+  for _, k in ipairs(keys) do
+    if n >= SyncMods.MAX_OPTION_KEYS then break end
+    local v = bucket[k]
+    if type(v) == "string" then v = v:sub(1, SyncMods.MAX_OPTION_TEXT) end
+    local finite = type(v) ~= "number"
+      or (v == v and v ~= math.huge and v ~= -math.huge)
+    if finite then
+      out[k] = v
+      n = n + 1
+    end
+  end
+  if n == 0 then return nil end
+  return out
+end
+
+local function sameOptions(a, b)
+  for k, v in pairs(a) do
+    if (b or {})[k] ~= v then return false end
+  end
+  return true
+end
+
 local function sourceOf(row)
   local github = row.github
     or (type(row.manifest) == "table" and row.manifest.github)
@@ -55,9 +98,14 @@ local function sourceOf(row)
   return "local"
 end
 
-function SyncMods.build(given)
+function SyncMods.build(given, includeOptions)
   local d = deps(given)
   local manifest = { rev = SyncMods.REV, indexes = {}, mods = {} }
+  local stored = {}
+  if includeOptions then
+    local ok, live = pcall(d.modOptions)
+    if ok and type(live) == "table" then stored = live end
+  end
   for _, row in ipairs(d.indexes() or {}) do
     local url = row.url or row.feed
     if type(url) == "string" and url ~= "" then
@@ -72,11 +120,14 @@ function SyncMods.build(given)
       for _, version in ipairs(versions()) do
         if answers[version] then enabledFor[#enabledFor + 1] = version end
       end
+      local options = includeOptions and sanitizeOptions(stored[row.id]) or nil
+      if options then manifest.hasOptions = true end
       manifest.mods[#manifest.mods + 1] = {
         id = row.id,
         version = row.version,
         source = sourceOf(row),
         enabledFor = enabledFor,
+        options = options,
       }
     end
   end
@@ -86,9 +137,16 @@ end
 
 function SyncMods.plan(manifest, given)
   local d = deps(given)
-  local plan = { indexes = {}, toInstall = {}, toEnable = {}, missing = {} }
+  local plan = { indexes = {}, toInstall = {}, toEnable = {}, missing = {},
+                 options = {}, applyOptions = nil }
   if type(manifest) ~= "table" then return plan end
 
+  local liveOptions = {}
+  do
+    local ok, live = pcall(d.modOptions)
+    if ok and type(live) == "table" then liveOptions = live end
+  end
+
   local haveIndex = {}
   for _, row in ipairs(d.indexes() or {}) do
     if type(row.url) == "string" then haveIndex[row.url] = true end
@@ -130,6 +188,10 @@ function SyncMods.plan(manifest, given)
             plan.toEnable[#plan.toEnable + 1] = { id = mod.id, version = version }
           end
         end
+        local wanted = sanitizeOptions(mod.options)
+        if wanted and not sameOptions(wanted, liveOptions[mod.id]) then
+          plan.options[#plan.options + 1] = { id = mod.id, values = wanted }
+        end
       end
     end
   end
@@ -138,10 +200,33 @@ end
 
 function SyncMods.planEmpty(plan)
   if type(plan) ~= "table" then return true end
+  if plan.applyOptions and #(plan.options or {}) > 0 then return false end
   return #(plan.indexes or {}) == 0 and #(plan.toInstall or {}) == 0
     and #(plan.toEnable or {}) == 0
 end
 
+function SyncMods.planHasOptions(plan)
+  return type(plan) == "table" and #(plan.options or {}) > 0
+end
+
+function SyncMods.optionsAnswered(plan)
+  return not SyncMods.planHasOptions(plan) or plan.applyOptions ~= nil
+end
+
+function SyncMods.answerOptions(plan, importThem)
+  if type(plan) ~= "table" then return false end
+  plan.applyOptions = importThem and true or false
+  return plan.applyOptions
+end
+
+function SyncMods.optionModIds(plan)
+  local out = {}
+  for _, row in ipairs((type(plan) == "table" and plan.options) or {}) do
+    out[#out + 1] = row.id
+  end
+  return out
+end
+
 function SyncMods.steps(plan, given)
   local d = deps(given)
   local out = {}
@@ -175,6 +260,19 @@ function SyncMods.steps(plan, given)
       return true
     end }
   end
+  if plan.applyOptions then
+    for _, want in ipairs(plan.options or {}) do
+      out[#out + 1] = { label = want.id, run = function()
+        if broken[want.id] then return true end
+        local ok, err = d.setOptions(want.id, want.values)
+        if ok == false then
+          return nil, want.id .. ": "
+            .. tostring(err or "could not set the mod options")
+        end
+        return true
+      end }
+    end
+  end
   return out
 end
 

tests/drivers/launcher_sync_shot.lua

@@ -22,6 +22,10 @@ return function(game)
     syncNow = function(self) self.status = "Checking for changes..." return true end,
     unlink = function(self) self.isLinked, self.codes = false, nil return true end,
     shareMods = function(self) self.shareCode = "K7QW3M" return true end,
+    answerModOptions = function(self, importThem)
+      if self.modPlan then self.modPlan.applyOptions = importThem and true or false end
+      return importThem
+    end,
     fetchShare = function(self) return true end,
     applyModPlan = function(self) self.modPlan = nil return true end,
     resolveConflict = function(self) self.conflicts = {} self.phase = "idle" return true end,
@@ -95,6 +99,24 @@ return function(game)
   U.log("share code:", tostring(eng.shareCode))
   shot("sync_mods.png")
 
+  eng.modPlan.options = {
+    { id = "jp_green", values = { language = "JP" } },
+    { id = "randomizer", values = { seed = 1234, wild = true } },
+    { id = "widescreen_hud", values = { scale = 2 } },
+  }
+  U.wait(2)
+  U.log("options question up:", tostring(eng.modPlan.applyOptions == nil))
+  shot("sync_mod_options.png")
+
+  love.window.setMode(800, 480, { resizable = true, highdpi = true })
+  U.wait(3)
+  shot("sync_mod_options_short.png")
+  imp:_syncAnswerModOptions(false)
+  U.wait(2)
+  shot("sync_mods_short.png")
+  love.window.setMode(1024, 768, { resizable = true, highdpi = true })
+  U.wait(3)
+
   eng.phase = "conflict"
   eng.status = "These saves were played at the same time."
   eng.conflicts = { {

tests/engine/launcher_sync_modal.lua

@@ -61,11 +61,16 @@ local function fakeEngine(over)
       self.isLinked, self.codes = false, nil
       return true
     end,
-    shareMods = function(self)
-      self.calls[#self.calls + 1] = { "shareMods" }
+    shareMods = function(self, withOptions)
+      self.calls[#self.calls + 1] = { "shareMods", withOptions }
       self.shareCode = "K7QW3M"
       return true
     end,
+    answerModOptions = function(self, importThem)
+      self.calls[#self.calls + 1] = { "answerModOptions", importThem }
+      if self.modPlan then self.modPlan.applyOptions = importThem and true or false end
+      return importThem
+    end,
     fetchShare = function(self, code)
       self.calls[#self.calls + 1] = { "fetchShare", code }
       return true
@@ -148,7 +153,16 @@ eq(imp._syncModal, nil, "escape closes the modal")
 
 imp:_openSync()
 imp:_syncView("mods")
+eq(imp._syncModal.withOptions, true,
+   "sharing carries the options that go with the mods by default")
 imp:_syncShareMods()
+eq(eng.calls[#eng.calls][2], true, "so the engine is told to include them")
+imp:_syncToggleShareOptions()
+eq(imp._syncModal.withOptions, false, "the toggle turns them off")
+imp:_syncShareMods()
+eq(eng.calls[#eng.calls][2], false,
+   "and a list can be shared with no options at all")
+imp:_syncToggleShareOptions()
 eq(eng.shareCode, "K7QW3M", "Share mod list asks the engine for a code")
 imp:_syncFocusField("share")
 imp:textinput("k7qw3m")
@@ -216,6 +230,22 @@ check(labels["Share mod list"], "the mod view shares a list")
 check(labels["Get mod list"], "and fetches one")
 check(labels["Apply these mods"], "a fetched plan can be applied")
 
+rEng.modPlan = { indexes = {}, toInstall = {}, toEnable = {}, missing = {},
+  options = { { id = "biggermod", values = { speed = 1 } },
+              { id = "another-one", values = { theme = "dark" } } } }
+labels = controls(rImp)
+check(labels["Import their options"],
+      "a list that carries options asks before importing them")
+check(labels["Keep my options"], "and offers to leave this device alone")
+check(not labels["Apply these mods"],
+      "the question is answered before anything is applied")
+rImp:_syncAnswerModOptions(false)
+eq(rEng.calls[#rEng.calls][2], false, "the answer reaches the engine")
+labels = controls(rImp)
+check(labels["Apply these mods"], "and the apply road opens again")
+check(not labels["Import their options"], "with the question gone")
+rEng.modPlan = nil
+
 rImp:_syncView("home")
 rEng.devices = {
   { id = "0a1b2c3d", label = "OS X", current = true },
@@ -304,4 +334,85 @@ check(pump and pump:find("self.launcher", 1, true) ~= nil,
 check(impSrc:find("_syncTypeInto", 1, true) ~= nil,
       "text input is routed through the code filter")
 
+do
+  local realCard = Kit.card
+  local card
+  Kit.card = function(x, y, w, h, variant)
+    card = { x = x, y = y, w = w, h = h }
+    realCard(x, y, w, h, variant)
+  end
+
+  local sizes = {
+    { 1080, 2400 }, { 2400, 1080 }, { 1280, 720 }, { 720, 1280 },
+    { 640, 960 }, { 480, 800 }, { 960, 540 }, { 800, 480 },
+  }
+  local views = {
+    { "home", function() end },
+    { "devices", function(_, e)
+        e.codes = { code1 = "1234-5678", code2 = "8765-4321" }
+        e.devices = { { id = "0a1b2c3d", label = "OS X", current = true },
+                      { id = "99998888", label = "Android" },
+                      { id = "77776666", label = "Steam Deck" } }
+      end },
+    { "link", function(i) i:_syncView("link") end },
+    { "mods", function(i, e)
+        i:_syncView("mods")
+        e.shareCode = "K7QW3M"
+        e.modPlan = { indexes = { "https://x" }, toInstall = { { id = "a" } },
+          toEnable = {}, missing = { { id = "z" } }, options = {} }
+      end },
+    { "mod options", function(i, e)
+        i:_syncView("mods")
+        e.modPlan = { indexes = {}, toInstall = {}, toEnable = {}, missing = {},
+          options = { { id = "biggermod" }, { id = "another-one" },
+                      { id = "a-third-one" } } }
+      end },
+    { "busy", function(i, e)
+        i:_syncView("mods")
+        e.isBusy = true
+        e.status = "Uploading the mod list and options..."
+      end },
+    { "conflict", function(_, e)
+        e.phase = "conflict"
+        e.conflicts = { { key = "red/abc", version = "red", overlap = true,
+          localMeta = { savedAt = 1700000000, sessionStart = 1699999000,
+            summary = { name = "ASH", badges = 3, timeText = "5:42", dexCount = 40 } },
+          remoteMeta = { savedAt = 1700000500, sessionStart = 1699999500,
+            summary = { name = "ASH", badges = 4, timeText = "6:10", dexCount = 44 } } } }
+      end },
+  }
+
+  local worst = { over = 0 }
+  for _, view in ipairs(views) do
+    for _, size in ipairs(sizes) do
+      love.graphics.getDimensions = function() return size[1], size[2] end
+      love.graphics.getPixelDimensions = love.graphics.getDimensions
+      local e = fakeEngine({ isLinked = true })
+      local i = launcher(e)
+      i:_openSync()
+      view[2](i, e)
+      Kit.audit = {}
+      card = nil
+      local ok = pcall(LauncherView.draw, i)
+      local rows = Kit.audit or {}
+      Kit.audit = nil
+      check(ok, ("the %s panel draws at %dx%d"):format(view[1], size[1], size[2]))
+      for _, r in ipairs(rows) do
+        if r.class == "control" and card then
+          local over = math.max((r.x + r.w) - (card.x + card.w),
+                                (r.y + r.h) - (card.y + card.h))
+          if over > worst.over then
+            worst = { over = over, view = view[1], w = size[1], h = size[2],
+                      label = r.label }
+          end
+        end
+      end
+    end
+  end
+  check(worst.over <= 0, ("no sync button leaves its card%s"):format(
+    worst.over > 0 and (": %s %dx%d overflows by %d at '%s'"):format(
+      worst.view, worst.w, worst.h, worst.over, worst.label) or ""))
+  Kit.card = realCard
+end
+
 T.finish("launcher_sync_modal")

tests/engine/sync_engine_test.lua

@@ -553,4 +553,109 @@ do
     "and the failure reaches the status line")
 end
 
+do
+  local shared = {}
+  local eng, transport = engine({
+    ["POST /sync/modshare"] = function(req)
+      shared[#shared + 1] = Json.decode(req.body)
+      return { code = 200, body = '{"code":"K7QW3M"}' }
+    end,
+  }, {})
+  eng.modDeps = {
+    installed = function()
+      return { { id = "alpha", version = "1.0.0",
+                 enabledByVersion = { red = true } } }
+    end,
+    indexes = function() return {} end,
+    modOptions = function() return { alpha = { speed = 3 } } end,
+    setOptions = function() return true end,
+  }
+
+  eng:shareMods(false)
+  pump(eng)
+  T.eq(shared[1].manifest.mods[1].options, nil,
+    "a shared list can leave the player's options at home")
+  T.eq(eng.shareCode, "K7QW3M", "and still mints a code")
+
+  eng:shareMods(true)
+  pump(eng)
+  T.eq(shared[2].manifest.mods[1].options.speed, 3,
+    "or carry the options that go with those mods")
+  T.eq(#transport.sent, 2, "one request each")
+end
+
+do
+  local eng = engine({
+    ["GET /sync/modshare"] = { code = 200, body =
+      '{"code":"K7QW3M","manifest":{"rev":2,"indexes":[],"hasOptions":true,' ..
+      '"mods":[{"id":"alpha","version":"1.0.0","enabledFor":["red"],' ..
+      '"options":{"speed":1}}]}}' },
+  }, {})
+  local written = {}
+  eng.modDeps = {
+    installed = function()
+      return { { id = "alpha", version = "1.0.0",
+                 enabledByVersion = { red = true } } }
+    end,
+    indexes = function() return {} end,
+    findEntry = function() return nil end,
+    addIndex = function() return true end,
+    install = function() return true end,
+    setEnabled = function() return true end,
+    modOptions = function() return { alpha = { speed = 3 } } end,
+    setOptions = function(id, values) written[id] = values return true end,
+  }
+
+  eng:fetchShare("K7QW3M")
+  pump(eng)
+  T.eq(#eng.modPlan.options, 1, "a fetched list reports the options it carries")
+  T.eq(eng.modPlan.applyOptions, nil, "without deciding for the player")
+  T.check(eng.status:find("options", 1, true) ~= nil,
+    "and the status line says there is a question to answer")
+  local ask = eng:modOptionsAsk()
+  T.eq(ask and ask[1], "alpha", "the launcher can name the mods it would touch")
+
+  eng:answerModOptions(false)
+  T.eq(eng:modOptionsAsk(), nil, "answering closes the question")
+  eng:applyModPlan()
+  pump(eng)
+  T.eq(next(written), nil, "declining leaves this device's options alone")
+
+  eng:fetchShare("K7QW3M")
+  pump(eng)
+  eng:answerModOptions(true)
+  eng:applyModPlan()
+  pump(eng)
+  T.eq(written.alpha.speed, 1, "accepting writes the sharer's values")
+end
+
+do
+  local eng = engine({
+    ["GET /sync/modshare"] = { code = 200, body =
+      '{"code":"K7QW3M","manifest":{"rev":2,"indexes":[],"hasOptions":true,' ..
+      '"mods":[{"id":"alpha","version":"1.0.0","enabledFor":["red"],' ..
+      '"options":{"speed":1}}]}}' },
+  }, {})
+  local written = {}
+  eng.modDeps = {
+    installed = function()
+      return { { id = "alpha", version = "1.0.0",
+                 enabledByVersion = { red = true } } }
+    end,
+    indexes = function() return {} end,
+    findEntry = function() return nil end,
+    addIndex = function() return true end,
+    install = function() return true end,
+    setEnabled = function() return true end,
+    modOptions = function() return { alpha = { speed = 3 } } end,
+    setOptions = function(id, values) written[id] = values return true end,
+  }
+  eng:fetchShare("K7QW3M")
+  pump(eng)
+  eng:applyModPlan()
+  pump(eng)
+  T.eq(next(written), nil,
+    "an apply that never asked imports nothing: silence is not consent")
+end
+
 T.finish("sync_engine")

tests/engine/sync_mods_test.lua

@@ -10,9 +10,14 @@ local function row(id, version, enabled, github)
            enabledByVersion = enabled }
 end
 
-local function deps(installed, indexes, catalog)
-  local calls = { installed = {}, enabled = {}, indexes = {} }
+local function deps(installed, indexes, catalog, modOptions)
+  local calls = { installed = {}, enabled = {}, indexes = {}, options = {} }
   return calls, {
+    modOptions = function() return modOptions or {} end,
+    setOptions = function(id, values)
+      calls.options[id] = values
+      return true
+    end,
     installed = function() return installed end,
     indexes = function() return indexes or {} end,
     addIndex = function(url)
@@ -145,4 +150,123 @@ do
   T.eq(#calls.installed, 0, "without the rest of the plan having run yet")
 end
 
+do
+  local live = {
+    alpha = { speed = 3, name = "ASH", on = true, bad = {} },
+    zeta = {},
+  }
+  local _, d = deps({
+    row("alpha", "2.1.0", { red = true }),
+    row("zeta", "1.0.0", { red = true }),
+  }, {}, {}, live)
+
+  local plain = SyncMods.build(d)
+  T.eq(plain.mods[1].options, nil,
+    "a mod list shares no options unless the player asks for it")
+  T.eq(plain.hasOptions, nil, "and is not flagged as carrying any")
+
+  local full = SyncMods.build(d, true)
+  T.eq(full.hasOptions, true, "opting in flags the list as carrying options")
+  T.eq(full.mods[1].options.speed, 3, "the player's own values ride along")
+  T.eq(full.mods[1].options.name, "ASH", "text values too")
+  T.eq(full.mods[1].options.on, true, "and toggles")
+  T.eq(full.mods[1].options.bad, nil,
+    "a nested table is never sent: only scalars cross the wire")
+  T.eq(full.mods[2].options, nil, "a mod with nothing set sends no bucket")
+end
+
+do
+  local wide = {}
+  for i = 1, SyncMods.MAX_OPTION_KEYS + 20 do wide["k" .. i] = i end
+  wide.huge = string.rep("x", SyncMods.MAX_OPTION_TEXT + 100)
+  local _, d = deps({ row("alpha", "1.0.0", { red = true }) }, {}, {},
+    { alpha = wide })
+  local manifest = SyncMods.build(d, true)
+  local n = 0
+  for _ in pairs(manifest.mods[1].options) do n = n + 1 end
+  T.eq(n, SyncMods.MAX_OPTION_KEYS, "an option bucket is capped")
+  local kept = manifest.mods[1].options.huge
+  T.check(kept == nil or #kept == SyncMods.MAX_OPTION_TEXT,
+    "and a long string is clamped when it makes the cut")
+end
+
+do
+  local manifest = { rev = 2, indexes = {}, hasOptions = true, mods = {
+    { id = "alpha", version = "2.1.0", enabledFor = { "red" },
+      options = { speed = 1, name = "MISTY" } },
+    { id = "beta", version = "1.0.0", enabledFor = { "red" },
+      options = { theme = "dark" } },
+    { id = "same", version = "1.0.0", enabledFor = { "red" },
+      options = { pitch = 5 } },
+    { id = "ghost", version = "0.1.0", enabledFor = { "red" },
+      options = { anything = 1 } },
+  } }
+  local calls, d = deps(
+    { row("alpha", "2.1.0", { red = true }), row("same", "1.0.0", { red = true }) },
+    {}, { beta = { id = "beta" } },
+    { alpha = { speed = 3, name = "ASH" }, same = { pitch = 5 } })
+
+  local plan = SyncMods.plan(manifest, d)
+  T.eq(#plan.options, 2, "only mods this device can actually run are listed")
+  T.eq(plan.options[1].id, "alpha", "the installed one whose values differ")
+  T.eq(plan.options[2].id, "beta", "and the one this plan installs")
+  for _, row in ipairs(plan.options) do
+    T.check(row.id ~= "same", "a mod already set that way is not busywork")
+    T.check(row.id ~= "ghost", "and a mod that cannot be installed is skipped")
+  end
+  T.eq(plan.applyOptions, nil, "nobody's options are imported unasked")
+  T.eq(SyncMods.planHasOptions(plan), true, "the plan reports it has some")
+  T.eq(SyncMods.optionsAnswered(plan), false, "and that the question is open")
+
+  local steps = SyncMods.steps(plan, d)
+  local labels = 0
+  for _, step in ipairs(steps) do
+    if step.label == "alpha" then labels = labels + 1 end
+  end
+  T.eq(labels, 0, "an unanswered plan writes no options")
+
+  SyncMods.answerOptions(plan, false)
+  T.eq(SyncMods.optionsAnswered(plan), true, "declining answers the question")
+  SyncMods.apply(plan, nil, d)
+  T.eq(next(calls.options), nil, "and keeps the options this device already had")
+
+  SyncMods.answerOptions(plan, true)
+  T.eq(plan.applyOptions, true, "accepting arms the option steps")
+  SyncMods.apply(plan, nil, d)
+  T.eq(calls.options.alpha.speed, 1, "the sharer's values are written")
+  T.eq(calls.options.alpha.name, "MISTY", "every key they set")
+  T.eq(calls.options.beta.theme, "dark", "including a mod installed by the plan")
+end
+
+do
+  local manifest = { rev = 2, indexes = {}, mods = {
+    { id = "alpha", version = "1.0.0", enabledFor = { "red" },
+      options = { speed = 1 } } } }
+  local calls, d = deps({ row("alpha", "1.0.0", { red = true }) }, {}, {},
+    { alpha = { speed = 3 } })
+  local plan = SyncMods.plan(manifest, d)
+  T.eq(SyncMods.planEmpty(plan), true,
+    "a list that only differs in options plans no mod work")
+  SyncMods.answerOptions(plan, true)
+  T.eq(SyncMods.planEmpty(plan), false,
+    "until the options are accepted, and then there is work to do")
+  d.install = function() return nil, "download failed" end
+  SyncMods.apply(plan, nil, d)
+  T.eq(calls.options.alpha.speed, 1, "which is just the option write")
+end
+
+do
+  local manifest = { rev = 2, indexes = {}, mods = {
+    { id = "beta", version = "1.0.0", enabledFor = { "red" },
+      options = { speed = 1 } } } }
+  local calls, d = deps({}, {}, { beta = { id = "beta" } })
+  d.install = function() return nil, "download failed" end
+  local plan = SyncMods.plan(manifest, d)
+  SyncMods.answerOptions(plan, true)
+  local ok = SyncMods.apply(plan, nil, d)
+  T.eq(ok, false, "a failed install still fails the apply")
+  T.eq(next(calls.options), nil,
+    "and the options of a mod that never installed are not written")
+end
+
 T.finish("sync_mods")