From a0f46d92e3434b88a62b5e592299a400e9d72825 Mon Sep 17 00:00:00 2001
From: nick evans <nick@rubinick.dev>
Date: Sun, 27 Sep 2026 13:29:17 -0400
Subject: [PATCH 1/3] =?UTF-8?q?=E2=99=BB=EF=B8=8F=20Refactor=20`SequenceSe?=
 =?UTF-8?q?t#at`=20and=20`#ordered=5Fat`?=
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This extracts a private inner API layer for number indexing and does the
input/output conversion in the public API layer.  The private API will
be more convenient to work with internally, since we don't need to worry
about accidentally comparing integers to `:*`.

This comes at the small cost of some duplication.  That duplication is
considered less important here because 1) it's very simple, and 2) the
implementations may drift apart:
* `#at` converts _indexable_ runs into indexable nums,
* `#ordered_at` converts _enumerable_ runs into indexable nums.
---
 lib/net/imap/sequence_set.rb | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/lib/net/imap/sequence_set.rb b/lib/net/imap/sequence_set.rb
index 827d331fe..054858b4c 100644
--- a/lib/net/imap/sequence_set.rb
+++ b/lib/net/imap/sequence_set.rb
@@ -1720,7 +1720,7 @@ def find_ordered_index(number)
       #
       # Related: #[], #slice, #ordered_at
       def at(index)
-        seek_number_in_minmaxes(minmaxes, index)
+        export_num sorted_set_num_at Integer index.to_int
       end
 
       # :call-seq: ordered_at(index) -> integer or nil
@@ -1733,7 +1733,7 @@ def at(index)
       #
       # Related: #[], #slice, #ordered_at
       def ordered_at(index)
-        seek_number_in_minmaxes(each_entry_minmax, index)
+        export_num ordered_list_num_at Integer index.to_int
       end
 
       # :call-seq:
@@ -2377,15 +2377,22 @@ def bsearch_range(num)  = (min, max = bsearch_minmax(num)) && (min..max)
       ######################################################################{{{2
       # Number indexing methods
 
+      def sorted_set_num_at(index)
+        seek_number_in_minmaxes(minmaxes, index)
+      end
+
+      def ordered_list_num_at(index)
+        seek_number_in_minmaxes(each_entry_minmax, index)
+      end
+
       def seek_number_in_minmaxes(minmaxes, index)
-        index = Integer(index.to_int)
         if index.negative?
           reverse_each_minmax_with_index(minmaxes) do |min, max, idx_min, idx_max|
-            idx_min <= index and return export_num(min + (index - idx_min))
+            idx_min <= index and return min + (index - idx_min)
           end
         else
           each_minmax_with_index(minmaxes) do |min, _, idx_min, idx_max|
-            index <= idx_max and return export_num(min + (index - idx_min))
+            index <= idx_max and return min + (index - idx_min)
           end
         end
         nil

From bb3db985b65a5f8876e5fe00972c4ee82ca86ec6 Mon Sep 17 00:00:00 2001
From: nick evans <nick@rubinick.dev>
Date: Sun, 27 Sep 2026 15:57:02 -0400
Subject: [PATCH 2/3] =?UTF-8?q?=E2=99=BB=EF=B8=8F=20Refactor=20`SequenceSe?=
 =?UTF-8?q?t#slice`=20internals?=
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---
 lib/net/imap/sequence_set.rb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/net/imap/sequence_set.rb b/lib/net/imap/sequence_set.rb
index 054858b4c..0b7e59ace 100644
--- a/lib/net/imap/sequence_set.rb
+++ b/lib/net/imap/sequence_set.rb
@@ -2421,8 +2421,8 @@ def slice_length(start, length)
         start  = Integer(start.to_int)
         length = Integer(length.to_int)
         raise ArgumentError, "length must be positive" unless length.positive?
-        last = start + length - 1 unless start.negative? && start.abs <= length
-        slice_range(start..last)
+        stop   = start + length unless start.negative? && start.abs <= length
+        slice_range(start...stop)
       end
 
       def slice_range(range)

From 4bf5bb4b6e348470cafd122baa367febb32c75e1 Mon Sep 17 00:00:00 2001
From: nick evans <nick@rubinick.dev>
Date: Mon, 28 Sep 2026 11:35:32 -0400
Subject: [PATCH 3/3] =?UTF-8?q?=E2=99=BB=EF=B8=8F=20Don't=20special-case?=
 =?UTF-8?q?=20`SequenceSet[start...2**32]`?=
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Since `set[2**32]` will _always_ be out of bounds, this makes no
difference to the semantics.  And it should have no effect on
performance.

Future performance optimizations can special case when we _know_ we must
be scanning to the end, but that would check for `STAR_INT <= last`.
---
 lib/net/imap/sequence_set.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/net/imap/sequence_set.rb b/lib/net/imap/sequence_set.rb
index 0b7e59ace..28a51fc9c 100644
--- a/lib/net/imap/sequence_set.rb
+++ b/lib/net/imap/sequence_set.rb
@@ -2430,7 +2430,7 @@ def slice_range(range)
         last  = range.end   || -1
         if range.exclude_end?
           return remain_frozen_empty if last.zero?
-          last -= 1 if range.end && last != STAR_INT
+          last -= 1 if range.end
         end
         if (first * last).positive? && last < first
           remain_frozen_empty