With my normal xemacs setup, I did M-x gnus.  After loading gnus-agent, xemacs crashes.

Here's the stack trace:

* thread #1: tid = 0x186690, 0x00007fff921dfd42 libsystem_kernel.dylib`__pthread_kill + 10, queue = 'com.apple.main-thread', stop reason = signal SIGABRT

  * frame #0: 0x00007fff921dfd42 libsystem_kernel.dylib`__pthread_kill + 10

    frame #1: 0x00007fff922cd5bf libsystem_pthread.dylib`pthread_kill + 90

    frame #2: 0x00007fff92145420 libsystem_c.dylib`abort + 129

    frame #3: 0x00000001000a26c9 xemacs`really_abort + 9 at emacs.c:4832

    frame #4: 0x000000010009f432 xemacs`assert_failed(file="/Volumes/share2/src/xemacs/hg/xemacs-21.5/src/elhash.c", line=1778, expr="RECORD_TYPEP (obj, lrecord_type_hash_table)") + 290 at emacs.c:4129

    frame #5: 0x0000000100094b03 xemacs`error_check_hash_table(obj=4373621248, file="/Volumes/share2/src/xemacs/hg/xemacs-21.5/src/elhash.c", line=1778) + 83 at elhash.h:26

    frame #6: 0x00000001000972ae xemacs`oblookup(package=4373621248, ptr="gwene.com.macosxhints", size=21) + 46 at elhash.c:1778

    frame #7: 0x0000000100097a99 xemacs`intern_istring(str="gwene.com.macosxhints", len=21, reloc=4304474984, package=4373621248) + 41 at elhash.c:1865

    frame #8: 0x00000001001c6f51 xemacs`read_atom(readcharfun=4344137728, firstchar=103) + 1377 at lread.c:2026

    frame #9: 0x00000001001c5f14 xemacs`read1(readcharfun=4344137728) + 4260 at lread.c:2890

    frame #10: 0x00000001001c1295 xemacs`read0(readcharfun=4344137728) + 21 at lread.c:1602

    frame #11: 0x00000001001c10e4 xemacs`Fread(stream=4344137728) + 292 at lread.c:1557

    frame #12: 0x00000001000ac8c4 xemacs`Ffuncall(nargs=2, args=0x00007fff5fbf5b88) + 1236 at eval.c:4203

    frame #13: 0x0000000100025bd1 xemacs`execute_optimized_program(program="`? }\x88\n\x1e\x12?

\n\"\x15?89\x15;?\x06?

         !\x89\x11??<?

                      !\x89\x10??4??w\x88?f?a?*?f?a?$?f?a?\x1e\r\b\tBL\x88?f?a?\x16\v?\x04? \x13??\r!\v\"?L\x88?\x05\r?L\x88ʇ", program_length=95, stack_depth=4, constants_data=0x0000000104411ac8) + 3585 at bytecode.c:954

    frame #14: 0x0000000100033e84 xemacs`Fbyte_code(instructions=4357565800, constants=4366342832, stack_depth=9) + 564 at bytecode.c:2887

    frame #15: 0x00000001000a5a9e xemacs`Feval(form=4373355352) + 3182 at eval.c:3949

    frame #16: 0x00000001000ab8b2 xemacs`condition_case_1(handlers=4348665744, bfun=(xemacs`Feval at eval.c:3805), barg=4373355352, hfun=(xemacs`run_condition_case_handlers at eval.c:2216), harg=4304474984) + 370 at eval.c:2193

    frame #17: 0x00000001000abe20 xemacs`condition_case_3(bodyform=4373355352, var=4304474984, handlers=4348665744) + 992 at eval.c:2275

    frame #18: 0x000000010002c379 xemacs`execute_rare_opcode(stack_ptr=0x00007fff5fbf6e08, stack_beg=0x00007fff5fbf6e00, stack_end=0x00007fff5fbf6e48, unused_program_ptr="\x88~\x88?y???-?, opcode=Bcondition_case) + 1865 at bytecode.c:1524

    frame #19: 0x00000001000250c7 xemacs`execute_optimized_program(program="\r?\x03\t\x15p\x0e0?!\x0e/?\n\r\tk?\x05\x0e/?\x14\r\tk?\t??ed\"!?\x04??!\x89\x16/\x1e0\x1e8eb\x88\x0e1ɘ?!\x88??\r\x1d\x18\r;\x83\x93", program_length=670, stack_depth=9, constants_data=0x0000000104411bd8) + 759 at bytecode.c:848

    frame #20: 0x00000001000b13b0 xemacs`funcall_compiled_function(fun=4371831960, nargs=2, args=0x00007fff5fbf77c0) + 1456 at eval.c:3784

    frame #21: 0x00000001000acd78 xemacs`Ffuncall(nargs=3, args=0x00007fff5fbf77b8) + 2440 at eval.c:4252

    frame #22: 0x0000000100025bd1 xemacs`execute_optimized_program(program="\U00000089!?\x1f\t\x18??ed\"!\x1b??!\x1a??\v\"\x88?

\v\"\x88? \x88?

!+\x87", program_length=36, stack_depth=4, constants_data=0x00000001043bbb88) + 3585 at bytecode.c:954

    frame #23: 0x00000001000b13b0 xemacs`funcall_compiled_function(fun=4375284472, nargs=1, args=0x00007fff5fbf8150) + 1456 at eval.c:3784

    frame #24: 0x00000001000acd78 xemacs`Ffuncall(nargs=2, args=0x00007fff5fbf8148) + 2440 at eval.c:4252

    frame #25: 0x0000000100025bd1 xemacs`execute_optimized_program(program="\r?\x03\t\x15p\x0e0?!\x0e/?\n\r\tk?\x05\x0e/?\x14\r\tk?\t??ed\"!?\x04??!\x89\x16/\x1e0\x1e8eb\x88\x0e1ɘ?!\x88??\r\x1d\x18\r;\x83\x93", program_length=670, stack_depth=9, constants_data=0x0000000104411bd8) + 3585 at bytecode.c:954

    frame #26: 0x00000001000b13b0 xemacs`funcall_compiled_function(fun=4371831960, nargs=4, args=0x00007fff5fbf8b00) + 1456 at eval.c:3784

    frame #27: 0x00000001000acd78 xemacs`Ffuncall(nargs=5, args=0x00007fff5fbf8af8) + 2440 at eval.c:4252

    frame #28: 0x0000000100025bd1 xemacs`execute_optimized_program(program="\v?,\x8a\bq\x88?

  !\x88?

        \f\"\x89\x1a?\t???

                          @#?\x13\n?a?\t?

                                         \t??$?\x06?

                                                    \t?#*\x87", program_length=47, stack_depth=6, constants_data=0x00000001043694b8) + 3585 at bytecode.c:954

    frame #29: 0x00000001000b13b0 xemacs`funcall_compiled_function(fun=4371831560, nargs=2, args=0x00007fff5fbf94a0) + 1456 at eval.c:3784

    frame #30: 0x00000001000acd78 xemacs`Ffuncall(nargs=3, args=0x00007fff5fbf9498) + 2440 at eval.c:4252

    frame #31: 0x0000000100025bd1 xemacs`execute_optimized_program(program="Ɖ\x1e:\x1e;\rA\x1d\x19\r;\x83\x91", program_length=1237, stack_depth=9, constants_data=0x0000000104369218) + 3585 at bytecode.c:954

    frame #32: 0x00000001000b13b0 xemacs`funcall_compiled_function(fun=4371831480, nargs=2, args=0x00007fff5fbf9cf0) + 1456 at eval.c:3784

    frame #33: 0x00000001000a625e xemacs`Feval(form=4344534224) + 5166 at eval.c:4010

    frame #34: 0x00000001000ab8b2 xemacs`condition_case_1(handlers=4344534152, bfun=(xemacs`Feval at eval.c:3805), barg=4344534224, hfun=(xemacs`run_condition_case_handlers at eval.c:2216), harg=4304474984) + 370 at eval.c:2193

    frame #35: 0x00000001000abe20 xemacs`condition_case_3(bodyform=4344534224, var=4304474984, handlers=4344534152) + 992 at eval.c:2275

    frame #36: 0x000000010002c379 xemacs`execute_rare_opcode(stack_ptr=0x00007fff5fbfa688, stack_beg=0x00007fff5fbfa680, stack_end=0x00007fff5fbfa6a8, unused_program_ptr="\x88??+\x87", opcode=Bcondition_case) + 1865 at bytecode.c:1524

    frame #37: 0x00000001000250c7 xemacs`execute_optimized_program(program="? \x88??? ?\v?

  !?\x06\v\nB?\x02\n? ?\x03?C\"\"?\x1c?\x8a\x0e\x11q\x88\f\x89A\x14@\x89\x15?\x1d\r\f????\\x0e\x14\"\x88????Џ\x88??+\x87", program_length=77, stack_depth=5, constants_data=0x0000000104369158) + 759 at bytecode.c:848

    frame #38: 0x00000001000b13b0 xemacs`funcall_compiled_function(fun=4371830440, nargs=2, args=0x00007fff5fbfb020) + 1456 at eval.c:3784

    frame #39: 0x00000001000acd78 xemacs`Ffuncall(nargs=3, args=0x00007fff5fbfb018) + 2440 at eval.c:4252

    frame #40: 0x0000000100025bd1 xemacs`execute_optimized_program(program="??!\x88\x0e3?\b\x0e0?\x04\x0e:???C\x1e=\x89\x1e/?\fɉ\x163\x160?:!\x88\x0e1\x83?, program_length=468, stack_depth=10, constants_data=0x000000010440f308) + 3585 at bytecode.c:954

    frame #41: 0x00000001000b13b0 xemacs`funcall_compiled_function(fun=4344543720, nargs=3, args=0x00007fff5fbfb9e0) + 1456 at eval.c:3784

    frame #42: 0x00000001000acd78 xemacs`Ffuncall(nargs=4, args=0x00007fff5fbfb9d8) + 2440 at eval.c:4252

    frame #43: 0x0000000100025bd1 xemacs`execute_optimized_program(program="\r?\t\v?\x06? \x88?L??!\x88?

!\x11\b?\x05\x0e\x1e?\x04? \x88\x0e\x1f?\t? \x88???"\x88\x0e ?\x06???"\x88???"\x88??\f\r#\x88??!\x88? \x88?

                 !\x88? \x88??!\x88? \x88??!\x88Շv'\x05", program_length=88, stack_depth=4, constants_data=0x000000010440eab8) + 3585 at bytecode.c:954

    frame #44: 0x0000000100033e84 xemacs`Fbyte_code(instructions=4344523880, constants=4366330528, stack_depth=9) + 564 at bytecode.c:2887

    frame #45: 0x00000001000a5a9e xemacs`Feval(form=4344529528) + 3182 at eval.c:3949

    frame #46: 0x00000001000a6d16 xemacs`Fprogn(args=4371016632) + 278 at eval.c:1038

    frame #47: 0x00000001000b8cd9 xemacs`unbind_to_hairy(count=12) + 201 at eval.c:7100

    frame #48: 0x0000000100025da9 xemacs`execute_optimized_program(program="? ?\x15? !\??\n\r?V?\x05\b@\r]!\x87? \x88? \x88??!\x88? \x88\x0e\x1a\x16\x1b? \x88\x0e\x1c?\x04? \x88?\x03\n?!\x89\x13+\x872\x90C", program_length=112, stack_depth=3, constants_data=0x000000010440ebd8) + 4057 at bytecode.c:965

    frame #49: 0x00000001000b13b0 xemacs`funcall_compiled_function(fun=4344466776, nargs=3, args=0x00007fff5fbfd0c0) + 1456 at eval.c:3784

    frame #50: 0x00000001000acd78 xemacs`Ffuncall(nargs=4, args=0x00007fff5fbfd0b8) + 2440 at eval.c:4252

    frame #51: 0x0000000100025bd1 xemacs`execute_optimized_program(program="??K!?\t??!\x88??!\x88?

\t\b#\x87", program_length=20, stack_depth=4, constants_data=0x0000000104330f18) + 3585 at bytecode.c:954

    frame #52: 0x00000001000b13b0 xemacs`funcall_compiled_function(fun=4371701272, nargs=1, args=0x00007fff5fbfda48) + 1456 at eval.c:3784

    frame #53: 0x00000001000acd78 xemacs`Ffuncall(nargs=2, args=0x00007fff5fbfda40) + 2440 at eval.c:4252

    frame #54: 0x00000001000382aa xemacs`Fcall_interactively(function=4304337104, record_flag=4304473664, keys=4304474984) + 9066 at callint.c:970

    frame #55: 0x00000001000b0014 xemacs`Fcommand_execute(cmd=4304337104, record_flag=4304473664, keys=4304474984) + 660 at eval.c:3407

    frame #56: 0x00000001000ac91d xemacs`Ffuncall(nargs=3, args=0x00007fff5fbfe0c8) + 1325 at eval.c:4203

@\x89??\f\x89??\x04!?\b\x88\x88?\r\x88\x88̫\b??\r@\"?\x02?!\x14)\t?Kt?H?ram="\r\x1d?

                                                                       !\f\x1a\x1b?

                                                                                   ?"\x88\v?8\b?\x13? ? a?\a? pa?\x06? \x88?\x04? \x88??!?\x1b???

                                                       A?\x04۪\x02?

?

 !#\"\x88?\x1f!\x88??!*\x87?

                            ?"\x87", program_length=167, stack_depth=7, constants_data=0x00000001009d0998) + 3585 at bytecode.c:954

    frame #58: 0x00000001000b13b0 xemacs`funcall_compiled_function(fun=4300610512, nargs=1, args=0x00007fff5fbfea68) + 1456 at eval.c:3784

    frame #59: 0x00000001000acd78 xemacs`Ffuncall(nargs=2, args=0x00007fff5fbfea60) + 2440 at eval.c:4252

    frame #60: 0x00000001000382aa xemacs`Fcall_interactively(function=4304284264, record_flag=4304474984, keys=4304474984) + 9066 at callint.c:970

    frame #61: 0x00000001000b0014 xemacs`Fcommand_execute(cmd=4304284264, record_flag=4304474984, keys=4304474984) + 660 at eval.c:3407

    frame #62: 0x00000001000d3bd1 xemacs`execute_command_event(command_builder=0x00000001021d5700, event=4348307136) + 817 at event-stream.c:4369

    frame #63: 0x00000001000d2c73 xemacs`Fdispatch_event(event=4348307136) + 2835 at event-stream.c:4704

    frame #64: 0x00000001000489e3 xemacs`Fcommand_loop_1 + 691 at cmdloop.c:623

    frame #65: 0x0000000100048492 xemacs`command_loop_1(unused_dummy=4304474984) + 66 at cmdloop.c:528

    frame #66: 0x00000001000ab8b2 xemacs`condition_case_1(handlers=4304473184, bfun=(xemacs`command_loop_1 at cmdloop.c:524), barg=4304474984, hfun=(xemacs`cmd_error at cmdloop.c:227), harg=4304474984) + 370 at eval.c:2193

    frame #67: 0x0000000100048fbd xemacs`command_loop_3 + 93 at cmdloop.c:285

    frame #68: 0x00000001000483f1 xemacs`command_loop_2(unused_dummy=4304474984) + 17 at cmdloop.c:298

    frame #69: 0x00000001000aaea7 xemacs`internal_catch(tag=4304063904, func=(xemacs`command_loop_2 at cmdloop.c:297), arg=4304474984, threw=0x0000000000000000, thrown_tag=0x0000000000000000, backtrace_before_throw=0x0000000000000000) + 311 at eval.c:1770

    frame #70: 0x00000001000482c0 xemacs`initial_command_loop(load_me=4304474984) + 352 at cmdloop.c:336

    frame #71: 0x000000010009f306 xemacs`xemacs_21_5_b34_x86_64_apple_darwin16_5_0(argc=1, argv=0x00007fff5fbff818, unused_envp=0x0000000000000000, restart=0) + 6582 at emacs.c:2778

    frame #72: 0x00000001000a1c4c xemacs`main(argc=1, argv=0x00007fff5fbff818, unused_envp=0x00007fff5fbff828) + 156 at emacs.c:3226

    frame #73: 0x00007fff920b1235 libdyld.dylib`start + 1

    frame #74: 0x00007fff920b1235 libdyld.dylib`start + 1

Lisp backtrace follows:

  # (unwind-protect ...)

  read(#<buffer " *nntpd*">)

  # bind (obarray)

  byte-code("..." [min max hashtb gnus-moderated-hashtb cur group gnus-point-at-eol read intern " " nil ?= ?x ?j ?m gnus-make-hashtable symbol-name t obarray] 4)

  # (condition-case ... . ((error (byte-code " ???? 9???? ??L??????ÁāŁ? ?? {#???€?" [ignore-errors group nil gnus-message 3 "Warning - invalid active: %s" gnus-point-at-bol gnus-point-at-eol] 5))))

  # bind (group max min cur hashtb real-active ignore-errors hashtb method)

  gnus-active-to-gnus-format(nil [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ...])

  # bind (file new gnus-command-method method)

  gnus-agent-save-active((nntp "news.gmane.org"))

  # bind (cur hashtb real-active ignore-errors hashtb method)

  gnus-active-to-gnus-format((nntp "news.gmane.org") [#:gwene\.com\.blogspot\.buddys\.party #:gwene\.com\.isthensastills\.blog #:gmane\.comp\.python\.sphinx\.user #:gmane\.linux\.watchdog #:gwene\.no\.geekhouse\.anders\.blog #:gmane\.user-groups\.foss\.brasil\.flisol #:nntp+news\.eternal-september\.org:alt\.binaries\.christian\.worship #:gwene\.com\.dankaminsky #:gmane\.comp\.emulators\.ovirt\.user #:gmane\.comp\.embedded\.lede\.devel #:gwene\.de\.ccc\.chaosradio\.chaosradio-lat #:gwene\.com\.wordpress\.solognu #:gwene\.com\.feedburner\.academic\.torrents\.rss\.feed-kickassto #:gwene\.com\.ssenhosting\.pod\.rss\.liveseoul\.podcast #:gmane\.network\.protocols\.alljoyn\.lighting #:gwene\.com\.github\.homebrew\.brew\.commits\.master #:gwene\.org\.boum\.tails\.news\.index\.de #:gwene\.org\.dhammatalks\.evening #:gwene\.com\.lexgill #:gwene\.com\.feedburner\.spiked\.math #:gwene\.org\.freedesktop\.cgit\.xcb\.proto\.master #:nntp+news\.eternal-september\.org:alt\.binaries\.christians #:gwene\.com\.blogoverflow\.gis #:gwene\.com\.anobii\.rss\.friend\.p\.0166449f046f13 #:gwene\.com\.stackexchange\.codereview\.feeds\.tag\.common-lisp #:gwene\.it\.stpauli\.commenti #:nntp+news\.eternal-september\.org:alt\.fan\.woody-allen #:gmane\.comp\.package-management\.rpm\.repoforge\.mirrors #:gwene\.org\.pdfbooksplanet #:gwene\.org\.locklessinc\.articles #:gmane\.comp\.java\.jersey\.announce #:gmane\.comp\.games\.godot\.devel #:gwene\.com\.livejournal\.devol #:gwene\.com\.dancinghacker\.blog #:gwene\.com\.ansibleworks\.blog\.author\.michaeldehaan #:gwene\.net\.xenosystems #:gwene\.org\.techtic\.blog #:gwene\.com\.ricardo\.galli\.software\.libre #:gwene\.com\.deepdotweb #:gwene\.com\.lotro\.forums\.lore-masters #:gwene\.com\.livejournal\.ibigdan #:gwene\.com\.heyash #:gwene\.com\.thegleebox\.tipjar #:gwene\.ua\.lb\.news #:gwene\.net\.kitenet\.joey #:gwene\.com\.youtube\.feeds\.videos\.ave #:gwene\.com\.tumblr\.iwdrm #:gwene\.edu\.stanford\.cyberlaw\.blog\.arvind\.narayanan #:gwene\.com\.thenewstribune\.sports\.nfl\.seattle\.seahawks\.insider\.blog #:gwene\.com\.feedburner\.the\.oracle\.base\.blog ...] nil t)

  # bind (list-type)

  # (unwind-protect ...)

  # bind (method groups)

  gnus-read-active-file-2(("gwene.com.macosxhints" "gmane.emacs.xemacs.beta" "gmane.emacs.xemacs.announce" "gmane.emacs.dvc.devel" "gmane.comp.version-control.mercurial.general" "gwene.comp.mathematics.maxima.bugs" "gmane.comp.mathematics.maxima.general" "gmane.lisp.slime.devel" "gmane.lisp.matlisp.user" "gmane.lisp.gcl.devel" "gmane.lisp.matlisp.devel" "gmane.lisp.editors.hints.devel" "gmane.lisp.ecl.general" "gmane.lisp.cmucl.general" "gmane.lisp.cmucl.devel" "gmane.lisp.cmucl.announce" "gmane.lisp.clx.devel" "gmane.lisp.clocc.announce" "gmane.lisp.clocc.devel" "gmane.lisp.clocc.general" "gmane.lisp.clisp.general" "gmane.lisp.clisp.devel" "gmane.lisp.clisp.announce" "gmane.lisp.common-lisp-net.devel" "gmane.lisp.asdf.announce" "gmane.lisp.asdf.devel") (nntp "news.gmane.org"))

  # bind (newsrc gmethod groups info where mesg force method)

  gnus-read-active-file-1((nntp "news.gmane.org") nil)

  # (condition-case ... . ((quit (message "Quit reading the active file"))))

  # (unwind-protect ...)

  # bind (methods method not-native force)

  gnus-read-active-file(nil nil)

  # bind (init nnmail-fetched-sources dont-connect level rawfile)

  gnus-setup-news(nil nil nil)

  byte-code("..." [gnus-slave gnus-current-startup-file gnus-startup-file did-connect level dont-connect gnus-group-quit gnus-run-hooks gnus-startup-hook gnus-make-newsrc-file gnus-dribble-read-file bbb-login add-hook gnus-summary-mode-hook gnus-grouplens-mode gnus-request-create-group "queue" (nndraft "") "drafts" (nndraft "") gnus-setup-news nil gnus-setup-news-hook gnus-start-draft-setup gnus-group-list-groups gnus-group-first-unread-group gnus-configure-windows group gnus-group-set-mode-line gnus-started-hook gnus-use-dribble-file gnus-use-grouplens gnus-agent] 4)

  # bind (level did-connect slave dont-connect arg)

  gnus-1(nil nil nil)

  # bind (slave dont-connect arg)

  gnus(nil)

  # bind (command-debug-status)

  call-interactively(gnus)

  command-execute(gnus t)

  # bind (#:execute-command-keys #:execute-command-name prefix-arg)

  execute-extended-command(nil)

  # bind (command-debug-status)

  call-interactively(execute-extended-command)

  (dispatch-event "[internal]")

  # (condition-case ... . error)

  # (catch top-level ...)

Abort trap: 6

--

Ray