Cell GPU cache must also key by screen type (primary/alternate)

src/Grid.zig

@@ -16,7 +16,13 @@ const lru = @import("lru.zig");
 
 const log = std.log.scoped(.grid);
 
-const CellsLRU = lru.AutoHashMap(terminal.Screen.RowHeader.Id, std.ArrayListUnmanaged(GPUCell));
+// The LRU is keyed by (screen, row_id) since we need to cache rows
+// separately for alt screens. By storing that in the key, we very likely
+// have the cache already for when the primary screen is reactivated.
+const CellsLRU = lru.AutoHashMap(struct {
+    screen: terminal.Terminal.ScreenType,
+    row_id: terminal.Screen.RowHeader.Id,
+}, std.ArrayListUnmanaged(GPUCell));
 
 alloc: std.mem.Allocator,
 
@@ -379,7 +385,10 @@ pub fn rebuildCells(self: *Grid, term: *Terminal) !void {
         defer y += 1;
 
         // Get our value from the cache.
-        const gop = try self.cells_lru.getOrPut(self.alloc, row.getId());
+        const gop = try self.cells_lru.getOrPut(self.alloc, .{
+            .screen = term.active_screen,
+            .row_id = row.getId(),
+        });
         if (!row.isDirty() and gop.found_existing) {
             var i: usize = self.cells.items.len;
             for (gop.value_ptr.items) |cell| {

src/terminal/Terminal.zig

@@ -27,7 +27,7 @@ const log = std.log.scoped(.terminal);
 const TABSTOP_INTERVAL = 8;
 
 /// Screen type is an enum that tracks whether a screen is primary or alternate.
-const ScreenType = enum {
+pub const ScreenType = enum {
     primary,
     alternate,
 };
@@ -172,6 +172,8 @@ pub fn alternateScreen(self: *Terminal, options: AlternateScreenOptions) void {
     const tracy = trace(@src());
     defer tracy.end();
 
+    //log.info("alt screen active={} options={} cursor={}", .{ self.active_screen, options, self.screen.cursor });
+
     // TODO: test
     // TODO(mitchellh): what happens if we enter alternate screen multiple times?
     // for now, we ignore...
@@ -199,6 +201,8 @@ pub fn primaryScreen(self: *Terminal, options: AlternateScreenOptions) void {
     const tracy = trace(@src());
     defer tracy.end();
 
+    //log.info("primary screen active={} options={}", .{ self.active_screen, options });
+
     // TODO: test
     // TODO(mitchellh): what happens if we enter alternate screen multiple times?
     if (self.active_screen == .primary) return;

src/terminal/stream.zig

@@ -51,7 +51,8 @@ pub fn Stream(comptime Handler: type) type {
             const actions = self.parser.next(c);
             for (actions) |action_opt| {
                 // if (action_opt) |action| {
-                //     log.info("action: {}", .{action});
+                //     if (action != .print)
+                //         log.info("action: {}", .{action});
                 // }
                 switch (action_opt orelse continue) {
                     .print => |p| if (@hasDecl(T, "print")) try self.handler.print(p),