✨ Add condstore kwarg to #select, #examine

Fixes ruby#122.

lib/net/imap.rb

@@ -507,6 +507,8 @@ module Net
   # ==== RFC7162: +CONDSTORE+
   #
   # - Updates #status with the +HIGHESTMODSEQ+ status attribute.
+  # - Updates #select and #examine with the +condstore+ modifier, and adds
+  #   either a +HIGHESTMODSEQ+ or +NOMODSEQ+ ResponseCode to the responses.
   # - Updates #search, #uid_search, #sort, and #uid_sort with the +MODSEQ+
   #   search criterion, and adds SearchResult#modseq to the search response.
   # - Updates #thread and #uid_thread with the +MODSEQ+ search criterion
@@ -1352,6 +1354,12 @@ def login(user, password)
     # or when existing messages are expunged; see #add_response_handler for a
     # way to detect these events.
     #
+    # When the +condstore+ keyword argument is true, the server is told to
+    # enable the extension.  If +mailbox+ supports persistence of mod-sequences,
+    # the +HIGHESTMODSEQ+ ResponseCode will be sent as an untagged response to
+    # #select and all `FETCH` responses will include FetchData#modseq.
+    # Otherwise, the +NOMODSEQ+ ResponseCode will be sent.
+    #
     # A Net::IMAP::NoResponseError is raised if the mailbox does not
     # exist or is for some reason non-selectable.
     #
@@ -1364,10 +1372,17 @@ def login(user, password)
     # response code indicating that the mailstore does not support persistent
     # UIDs:
     #   imap.responses("NO", &:last)&.code&.name == "UIDNOTSTICKY"
-    def select(mailbox)
+    #
+    # If [CONDSTORE[https://www.rfc-editor.org/rfc/rfc7162.html]] is supported,
+    # the +condstore+ keyword parameter may be used.
+    #   imap.select("mbox", condstore: true)
+    #   modseq = imap.responses("HIGHESTMODSEQ", &:last)
+    def select(mailbox, condstore: false)
+      args = ["SELECT", mailbox]
+      args << ["CONDSTORE"] if condstore
       synchronize do
         @responses.clear
-        send_command("SELECT", mailbox)
+        send_command(*args)
       end
     end
 
@@ -1380,10 +1395,12 @@ def select(mailbox)
     # exist or is for some reason non-examinable.
     #
     # Related: #select
-    def examine(mailbox)
+    def examine(mailbox, condstore: false)
+      args = ["EXAMINE", mailbox]
+      args << ["CONDSTORE"] if condstore
       synchronize do
         @responses.clear
-        send_command("EXAMINE", mailbox)
+        send_command(*args)
       end
     end
 

test/net/imap/fake_server/command_reader.rb

@@ -33,7 +33,7 @@ def parse(buf)
       /\A([^ ]+) ((?:UID )?\w+)(?: (.+))?\r\n\z/min =~ buf or
         raise "bad request: %p" [buf]
       case $2.upcase
-      when "LOGIN", "SELECT", "ENABLE", "AUTHENTICATE"
+      when "LOGIN", "SELECT", "EXAMINE", "ENABLE", "AUTHENTICATE"
         Command.new $1, $2, scan_astrings($3), buf
       else
         Command.new $1, $2, $3, buf # TODO...

test/net/imap/fake_server/command_router.rb

@@ -132,13 +132,13 @@ def handler_for(command)
       permanentflags: %i[Deleted Seen *].freeze,
     }.freeze
 
-    on "SELECT" do |resp|
+    def select_handler(command, resp)
       state.user or return resp.fail_bad_state(state)
       name, args = resp.args
       name or return resp.fail_bad_args
       name = name.upcase if name.to_s.casecmp? "inbox"
       mbox = config.mailboxes[name]
-      mbox or return resp.fail_no "invalid mailbox"
+      mbox or return resp.fail_no "invalid mailbox %p" % [name]
       state.select mbox: mbox, args: args
       attrs = RFC3501_6_3_1_SELECT_EXAMPLE_DATA.merge mbox.to_h
       resp.untagged "%{exists} EXISTS" % attrs
@@ -153,9 +153,13 @@ def handler_for(command)
       resp.untagged "OK [PERMANENTFLAGS (%s)] Limited" % [
         flags(attrs[:permanentflags])
       ]
-      resp.done_ok code: "READ-WRITE"
+      code = command == "SELECT" ? "READ-WRITE" : "READ-ONLY"
+      resp.done_ok code: code
     end
 
+    on "SELECT"  do |resp| select_handler "SELECT",  resp end
+    on "EXAMINE" do |resp| select_handler "EXAMINE", resp end
+
     on "CLOSE", "UNSELECT" do |resp|
       resp.args.nil? or return resp.fail_bad_args
       state.unselect

test/net/imap/test_imap.rb

@@ -1120,6 +1120,22 @@ def test_clear_responses
     end
   end
 
+  test "#select with condstore" do
+    with_fake_server do |server, imap|
+      imap.select "inbox", condstore: true
+      assert_equal("RUBY0001 SELECT inbox (CONDSTORE)",
+                   server.commands.pop.raw.strip)
+    end
+  end
+
+  test "#examine with condstore" do
+    with_fake_server do |server, imap|
+      imap.examine "inbox", condstore: true
+      assert_equal("RUBY0001 EXAMINE inbox (CONDSTORE)",
+                   server.commands.pop.raw.strip)
+    end
+  end
+
   def test_close
     with_fake_server(select: "inbox") do |server, imap|
       resp = imap.close