fix(theme): give migrated V1 dialogs an opaque background (#60016)

packages/theme/src/tui/v1-migrate-new-designs.ts

@@ -9,6 +9,7 @@ import {
   categoricalTokens,
   chromaticHues,
   detectMode,
+  dialogBackground,
   hex,
   inferHues,
   referenceHues,
@@ -28,7 +29,7 @@ export function migrateV1NewDesigns(theme: ThemeV1Json): ThemeDocument {
     const darkMode = detectMode(dark)
     if (lightMode === darkMode) {
       const definition = migrateMode(lightMode === "light" ? light : dark, lightMode)
-      if (lightMode === "light") return { base: base(definition), light: lightOverrides(definition) }
+      if (lightMode === "light") return { base: base(definition), light: lightOverrides(definition, light) }
       return { base: base(definition), dark: { hue: definition.hue } }
     }
   }
@@ -36,7 +37,7 @@ export function migrateV1NewDesigns(theme: ThemeV1Json): ThemeDocument {
   const darkDefinition = migrateMode(dark, "dark")
   return {
     base: base(lightDefinition),
-    light: lightOverrides(lightDefinition),
+    light: lightOverrides(lightDefinition, light),
     dark: darkDefinition,
   }
 }
@@ -53,8 +54,12 @@ const lightDialog = {
   },
 } satisfies ModeDefinition["@dialog"]
 
-function lightOverrides(definition: ThemeDefinition): ModeDefinition {
-  return { hue: definition.hue, "@dialog": lightDialog }
+function lightOverrides(definition: ThemeDefinition, theme: Theme): ModeDefinition {
+  if (theme.backgroundPanel.a === 1) return { hue: definition.hue, "@dialog": lightDialog }
+  return {
+    hue: definition.hue,
+    "@dialog": { ...lightDialog, background: { ...lightDialog.background, base: dialogBackground(theme) } },
+  }
 }
 
 // Mirrors the opencode2 token layout: text at 100/200/300, the page at 900, raised surfaces at 700/600/500,
@@ -125,7 +130,7 @@ function migrateMode(theme: Theme, mode: Mode): ThemeDefinition {
     ...paletteTokens(theme),
     "@dialog": {
       background: {
-        base: "$background.raised.base",
+        base: dialogBackground(theme),
         action: {
           primary: { $hovered: "$background.raised.max" },
           secondary: { $hovered: "$background.raised.max" },

packages/theme/src/tui/v1-migrate.ts

@@ -217,13 +217,25 @@ function migrateMode(theme: Theme, mode: Mode): ThemeDefinition {
     },
     "@dialog": {
       background: {
-        base: "$background.raised.base",
+        base: dialogBackground(theme),
         action: { primary: { $hovered: "$background.raised.high" } },
       },
     },
   })
 }
 
+// Dialogs float over the session, so a see-through panel would let the content underneath show through them.
+// Fall back to the first visible surface color, made opaque.
+export function dialogBackground(theme: Theme) {
+  if (theme.backgroundPanel.a === 1) return "$background.raised.base"
+  const visible = [theme.backgroundPanel, theme.backgroundMenu, theme.backgroundElement, theme.background].find(
+    (color) => color.a > 0,
+  )
+  if (!visible) return luminance(theme.text) > 0.5 ? "#000000" : "#ffffff"
+  const [red, green, blue] = visible.toInts()
+  return hexInts(red, green, blue, 255)
+}
+
 export function referenceHues(theme: ThemeDefinition): ThemeDefinition {
   const definitions = theme.hue as Record<string, string | Partial<Record<HueStep, string>>> | undefined
   if (!definitions) return theme

packages/tui/test/theme/v2/v1-migrate.test.ts

@@ -279,6 +279,42 @@ test("collapses identical V1 backgrounds when both variants infer one mode", ()
   expect(selectThemeMode(migratedLight, "dark").mode).toBe("light")
 })
 
+test("gives dialogs an opaque background when V1 panels are see-through", () => {
+  const lucent = DEFAULT_THEMES["lucent-orng"]!
+  for (const mode of ["dark", "light"] as const) {
+    const legacy = resolveV1(lucent, mode)
+    const dialog = resolveThemeDocument(migrateV1(lucent), mode).surface("dialog")
+    expect(legacy.backgroundPanel.a).toBe(0)
+    const [red, green, blue] = legacy.backgroundMenu.toInts()
+    expect(legacy.backgroundMenu.a).toBeLessThan(1)
+    expect(dialog.background.base.toInts()).toEqual([red, green, blue, 255])
+  }
+
+  const source = structuredClone(opencodeV1)
+  source.theme.background = "transparent"
+  source.theme.backgroundPanel = "transparent"
+  source.theme.backgroundElement = "transparent"
+  source.theme.backgroundMenu = "transparent"
+  expect(hex(resolveThemeDocument(migrateV1(source), "dark").surface("dialog").background.base)).toBe("#000000")
+  expect(hex(resolveThemeDocument(migrateV1(source), "light").surface("dialog").background.base)).toBe("#ffffff")
+
+  const opaque = resolveThemeDocument(migrateV1(opencodeV1), "dark")
+  expect(hex(opaque.surface("dialog").background.base)).toBe(hex(opaque.background.raised.base))
+})
+
+test("gives new designs dialogs an opaque background when V1 panels are see-through", () => {
+  const lucent = DEFAULT_THEMES["lucent-orng"]!
+  for (const mode of ["dark", "light"] as const) {
+    const [red, green, blue] = resolveV1(lucent, mode).backgroundMenu.toInts()
+    const dialog = resolveThemeDocument(migrateV1NewDesigns(lucent), mode).surface("dialog")
+    expect(dialog.background.base.toInts()).toEqual([red, green, blue, 255])
+  }
+
+  const opaque = migrateV1NewDesigns(DEFAULT_THEMES.tokyonight!)
+  expect(opaque.base["@dialog"]?.background?.base).toBe("$background.raised.base")
+  expect(opaque.light?.["@dialog"]?.background?.base).toBe("$hue.neutral.800")
+})
+
 test("keeps both modes when a shared background has different contrast", () => {
   const source = structuredClone(opencodeV1)
   source.theme.background = "#808080"