diff -r f610d705c3ca -r de5bf3fe0233 mercurial/revsetlang.py
--- a/mercurial/revsetlang.py	Tue Apr 09 14:41:48 2024 +0200
+++ b/mercurial/revsetlang.py	Fri Apr 05 11:05:54 2024 +0200
@@ -392,7 +392,7 @@
     elif op == b'negate':
         s = getstring(x[1], _(b"can't negate that"))
         return _analyze((b'string', b'-' + s))
-    elif op in (b'string', b'symbol', b'smartset'):
+    elif op in (b'string', b'symbol', b'smartset', b'nodeset'):
         return x
     elif op == b'rangeall':
         return (op, None)
@@ -441,8 +441,9 @@
         return 0, x
 
     op = x[0]
-    if op in (b'string', b'symbol', b'smartset'):
-        return 0.5, x  # single revisions are small
+    if op in (b'string', b'symbol', b'smartset', b'nodeset'):
+        # single revisions are small, and set of already computed revision are assumed to be cheap.
+        return 0.5, x
     elif op == b'and':
         wa, ta = _optimize(x[1])
         wb, tb = _optimize(x[2])
@@ -784,6 +785,8 @@
             if isinstance(arg, set):
                 arg = sorted(arg)
             ret.append(_formatintlist(list(arg)))
+        elif t == b'nodeset':
+            ret.append(_formatlistexp(list(arg), b"n"))
         else:
             raise error.ProgrammingError(b"unknown revspec item type: %r" % t)
     return b''.join(ret)
@@ -801,6 +804,10 @@
             newtree = (b'smartset', smartset.baseset(arg))
             inputs.append(newtree)
             ret.append(b"$")
+        elif t == b'nodeset':
+            newtree = (b'nodeset', arg)
+            inputs.append(newtree)
+            ret.append(b"$")
         else:
             raise error.ProgrammingError(b"unknown revspec item type: %r" % t)
     expr = b''.join(ret)
@@ -863,6 +870,12 @@
                 ret.append((b'baseset', arg))
                 pos += 1
                 continue
+            elif islist and d == b'n' and arg:
+                # we cannot turn the node into revision yet, but not
+                # serializing them will same a lot of time for large set.
+                ret.append((b'nodeset', arg))
+                pos += 1
+                continue
             try:
                 ret.append((None, f(list(arg), d)))
             except (TypeError, ValueError):