* lisp/calendar/time-date.el (with-decoded-time-value):
Prefer time-convert to current-time on the off chance that code
will use this obsolete macro even after current-time returns pairs.

This should complete the fix for Bug#52209.
* lisp/calendar/time-date.el (date-to-time): Apply
decoded-time-set-defaults only to the output of (parse-time-string
date), and only when the output has a year (to avoid confusion
when dates lack years).  There is no point applying it after
timezone-make-date-arpa-standard since the latter fills in all the
blanks.  And the former code mistakenly called encode-time on an
already-encoded time.  This goes back to the code a couple of days
ago, except with changed behavior (to fix Bug#52209) only when
timezone-make-date-arpa-standard is not called.
* test/lisp/calendar/time-date-tests.el (test-date-to-time)
(test-days-between): New tests.

* lisp/calendar/time-date.el (date-to-time): The function needs to
test if `parse-time-string' returns a valid data as the old
version did it with the help of `encode-time' (bug#52209).

* lisp/calendar/time-date.el (date-to-time): Try harder to parse
dates with no times (bug#52209).

* lisp/calendar/icalendar.el (icalendar--decode-isodatetime):
Parse time zones more correctly.
* test/lisp/calendar/icalendar-tests.el
(icalendar-tests--decode-isodatetime): Fix tests so that they work
in other time zones than Europe/Berlin (bug#51959).

* lisp/calendar/time-date.el (decoded-time-add): Add a usage example.

* lisp/vc/ediff-init.el (ediff-BAD-INFO):
* lisp/url/url-ldap.el (url-ldap):
* lisp/url/url-http.el (url-http--user-agent-default-string):
* lisp/textmodes/reftex.el (reftex-access-parse-file):
* lisp/textmodes/reftex-index.el (reftex-index-phrases-info):
* lisp/textmodes/ispell.el (ispell-create-debug-buffer):
* lisp/term.el (serial-read-speed):
* lisp/progmodes/verilog-mode.el (verilog-scan-debug):
* lisp/progmodes/idlwave.el (idlwave-find-module):
* lisp/progmodes/compile.el (compilation-revert-buffer):
* lisp/org/org-agenda.el (org-search-view):
* lisp/net/telnet.el (telnet-revert-buffer):
* lisp/net/soap-inspect.el (soap-sample-value-for-xs-simple-type):
* lisp/net/newst-backend.el (newsticker--cache-read):
* lisp/mh-e/mh-seq.el (mh-msg-is-in-seq):
* lisp/mail/smtpmail.el (smtpmail-via-smtp):
* lisp/mail/emacsbug.el (report-emacs-bug):
* lisp/jsonrpc.el (jsonrpc-error):
* lisp/help-fns.el (describe-variable):
* lisp/gnus/mm-decode.el (mm-possibly-verify-or-decrypt):
* lisp/gnus/gnus.el (gnus-group-startup-message):
(gnus-group-startup-message):
* lisp/gnus/gnus-group.el (gnus-group-restart):
* lisp/frame.el (make-frame-on-display):
* lisp/emulation/viper-ex.el (ex-help):
* lisp/calendar/icalendar.el (icalendar--convert-ical-to-diary):
(icalendar--add-diary-entry):
* lisp/calendar/cal-tex.el (cal-tex-end-document):
* lisp/calc/calcalg3.el (math-ninteg-romberg): Don't use `format'
on strings that have no % format directives in them.

* lisp/autoarg.el (autoarg-mode):
* lisp/bookmark.el (bookmark-set, bookmark-set-no-overwrite)
(bookmark-save):
* lisp/calendar/todo-mode.el (todo-insert-item)
(todo-filter-top-priorities)
(todo-filter-top-priorities-multifile):
* lisp/dired-x.el (dired-mark-extension, dired-mark-suffix):
* lisp/eshell/eshell.el (eshell):
* lisp/gnus/gnus-group.el (gnus-group-find-new-groups):
* lisp/gnus/gnus-start.el (gnus-find-new-newsgroups):
* lisp/gnus/gnus-sum.el (gnus-summary-show-article):
* lisp/gnus/gnus.el (gnus-secondary-servers):
* lisp/org/org-timer.el (org-timer-set-timer):
* lisp/org/ox.el (org-export-dispatch-last-position):
* lisp/printing.el (pr-ps-directory-preview)
(pr-ps-directory-using-ghostscript, pr-ps-directory-print)
(pr-ps-directory-ps-print, pr-ps-buffer-preview)
(pr-ps-buffer-using-ghostscript, pr-ps-buffer-print)
(pr-ps-buffer-ps-print, pr-despool-preview)
(pr-despool-using-ghostscript, pr-despool-print)
(pr-despool-ps-print, pr-ps-file-up-ps-print, pr-ps-fast-fire)
(pr-txt-fast-fire):
* lisp/progmodes/idlwave.el (idlwave-complete):
* lisp/progmodes/sh-script.el (sh-set-shell):
* lisp/replace.el (occur):
* lisp/ses.el (ses--advice-yank):
* lisp/simple.el (set-mark-command-repeat-pop):
* lisp/sort.el (delete-duplicate-lines):
* lisp/strokes.el (strokes-help):
* lisp/textmodes/artist.el (artist-mode):
* lisp/textmodes/reftex-cite.el (reftex-citation):
* lisp/textmodes/reftex-dcr.el (reftex-view-crossref):
* lisp/textmodes/reftex-index.el (reftex-index-selection-or-word)
(reftex-display-index):
* lisp/textmodes/reftex-ref.el (reftex-reference):
* lisp/textmodes/reftex-toc.el (reftex-toc):
* lisp/textmodes/reftex-vars.el (reftex-cite-prompt-optional-args)
(reftex-enable-partial-scans):
* lisp/textmodes/texnfo-upd.el (texinfo-master-menu):
* lisp/windmove.el (windmove-display-in-direction)
(windmove-delete-left, windmove-delete-up)
(windmove-delete-right, windmove-delete-down):
* lisp/window.el (recenter-window-group, recenter-other-window): Use
command substitution for 'universal-argument' instead of raw "C-u".