Manage some text props for ERC insertion-hook members

Manage some text props for ERC insertion-hook members

* etc/ERC-NEWS: Mention that ERC only adds the text property
`cursor-sensor-functions' when `erc-echo-timestamps' is enabled.  Also
mention that date stamps are now inserted as separate messages.
* lisp/erc/erc-fill.el (erc-fill): Look for text prop `erc-cmd'
instead of `erc-command' and use helper utility to do so.
(erc-fill-static): Skip date stamps because this fill style leaves
them flush left.
(erc-fill-wrap-mode, erc-fill-wrap-enable, erc-fill-wrap-disable):
Don't hook on the soon-to-be-removed function interface
`erc-stamp--insert-date-function' because date stamps are now separate
messages.
(erc-fill--wrap-continued-message-p): Restore accidentally discarded
doc string.  Derive context about current message from text props at
`point-min', and use updated property names and utility functions.
Abort when previous message is now hidden.
(erc-fill--wrap-stamp-insert-prefixed-date): Remove unused function,
originally meant to be new in ERC 5.6, and move logic for date-stamp
measuring portion directly to `erc-fill-wrap' itself.
(erc-fill--wrap-measure): New helper function.
(erc-fill-wrap): Use helper `erc-fill--wrap-measure' and incorporate
date-stamp detection and width measuring from removed helper.  Don't
dedent first word for messages of unknown origin, such as those
inserted by `erc-display-line' alone without prior preparation from
`erc-display-message'.
* lisp/erc/erc-goodies.el (erc-readonly-mode, erc-readonly-enable):
Set hook depth explicitly to 70.
* lisp/erc/erc-stamp.el (erc-timestamp-format-left): Mention that a
trailing newline is implicit if not provided and that users who don't
want date stamps should use `erc-timestamp-format-right' instead.
(erc-stamp-mode, erc-stamp-enable): Call `erc-stamp--setup' instead
of `erc-munge-invisibility-spec', and bump hook depth for
`erc-add-timestamp' to 70.
(erc-stamp--current-time): Use `erc-ts' instead of `erc-timestamp'
text property in doc string.
(erc-stamp--skip): New internal variable.
(erc-stamp--allow-unmanaged): New variable for legacy code to force
`erc-add-timestamps' to run when `erc--msg-props' is nil.
(erc-add-timestamp): Always run when `erc-stamp--allow-unmanaged' is
non-nil unless `erc-stamp--skip' is as well because the latter takes
precedence.  Don't add `erc-ts' text prop directly unless
`erc-stamp--allow-unmanaged is non-nil.  Instead, use the new
`erc--msg-props' facility to defer until after modification hooks.
Likewise, don't add `cursor-senor-functions' directly either unless
the same compatibility flag is enabled.  Instead, expect the latter to
be handled by a post-modify hook conditioned on the option
`erc-echo-timestamps'.
(erc-timestamp-last-inserted-left): Mention that the final trailing
newline specified in the format string no longer appears in the
recorded value.
(erc-stamp-prefix-log-filter): Use updated name for timestamp
property as well as helper utility for accessing it.
(erc-stamp--inherited-props): Add doc string.
(erc-insert-timestamp-right): Fix bug involving object cycle where
the time-stamp string would appear in its own `display' property.
(erc-stamp--insert-date-function, erc-stamp--insert-date-hook): Remove
unused internal function-valued interface variable and replace with
the latter, a normal hook.
(erc-stamp--date-format-end, erc-stamp--propertize-left-date-stamp):
New function and auxiliary variable to apply date stamp properties at
the post-modify stage.  Add text property `erc-stamp-type' to inserted
date stamps to help folks distinguish between them and other
left-sided stamps.
(erc-stamp--current-datestamp-left,
erc-stamp--format-date-stamp,
erc-stamp--insert-date-stamp-as-phony-message,
erc-stamp--lr-date-on-pre-modify): New functions and state variable to
help ERC treat date stamps as separate messages while working within
the established mechanism for processing inserted messages.  Shadow
`erc-stamp--invisible-property' when calling `erc-format-timestamp' in
order to prevent date stamps from inheriting other `invisible' props.
These date stamps are special in that they have no business being
hidden along with the current message.
(erc-insert-timestamp-left-and-right): On initial run in any buffer,
remember whether the date stamp needed newline massaging on insertion.
Move all business for inserting date stamps to post-modify hooks, but
run them forcibly if this is the very first date stamp in the current
buffer.  Also mention some specifics related to relevant text props in
the doc string.
(erc-format-timestamp): Don't add `invisible' prop to stamp unless
`erc-stamp--invisible-property' is non-nil.
(erc-stamp--csf-props-updated-p): New local variable.
(erc-munge-invisibility-spec): Restore `cursor-sensor-functions' text
property for existing messages when a user enables the option
mid-session.  Add and remove hooks for use with automatic timestamp
echoing.
(erc-stamp--add-csf-on-post-modify): New function to add
`cursor-sensor-functions' property on post-modify hooks.
(erc-stamp--setup): Perform some additional teardown.
(erc-stamp--on-clear-message): Look for text property `erc-ts' instead
of `erc-timestamp'.
(erc-echo-timestamp, erc--echo-ts-csf): Use utility to find time-stamp
text prop in current message.
(erc-stamp--update-saved-position, erc-stamp--reset-on-clear): Use
hook `erc-stamp--insert-date-hook' instead of excised function-valued
variable interface `erc-stamp--insert-date-function'.
* lisp/erc/erc-truncate.el (erc-truncate-buffer-to-size): Use internal
utility to find beginning of message.
* lisp/erc/erc.el (erc--msg-props, erc--msg-props-overrides): New
internal variables for initializing and conveying metadata-oriented
text properties among insert and send hooks.
(erc-insert-modify-hook): Mention reserved depth ranges for built-in
members in doc string.
(erc-send-action):  Use convenience variable to modifying text props
instead of awkwardly overriding `erc-insert-pre-hook'.
(erc--check-msg-prop, erc--get-inserted-msg-bounds,
erc--get-inserted-msg-prop, erc--with-inserted-msg,
erc--traverse-inserted): New utility functions and macros to help
modules find metadata and message-delimiting text props.
(erc-display-line-1): Ensure the first character of every message in
an ERC buffer has the `erc-msg' property, as well as any other props
in `erc--msg-props', when populated.
(erc--hide-message): Don't bother offsetting start of first message in
a buffer.
(erc--ranked-properties, erc--order-text-properties-from-hash): New
variable and function to convert `erc--msg-props' into a plist
suitable for `add-text-properties'.
(erc-display-message): Make doc string more informative.  Bind and
initialize `erc--msg-props' for use by all hooks.  Respect
`erc--msg-prop-overrides' when non-nil.  Don't add `erc-command'
property.  Instead, ensure `erc--msg-props' contains an `erc-cmd' item
when the parameter PARSED is non-nil.
(erc--own-property-names): Add `erc-stamp-type'.
(erc--get-speaker-bounds): Use helper to find message start.
(erc-process-ctcp-query, erc-send-current-line): Use convenience
variable to leverage framework for manipulating message metadata
instead of overriding `erc-insert-pre-hook'.
(erc-display-msg): Bind `erc--msg-props' for use by all send-related
hooks.  Add text props from table after `erc-send-post-hook'.
(erc-restore-text-properties): Improve doc string.
(erc--get-eq-comparable-cmd): Use `if-let' instead of `if-let*'.
* test/lisp/erc/erc-fill-tests.el (erc-fill-tests--insert-privmsg):
Make phony message more realistic.
(erc-fill-tests--wrap-populate): Shorten overlong line.
(erc-fill-tests--wrap-check-prefixes): Make test utility more vigilant
in asserting no gaps exist in `line-prefix' property interval.
(erc-fill-tests--compare): Compare text props on text-prop values that
are themselves strings.
* test/lisp/erc/erc-scenarios-log.el (erc-scenarios-log--clear-stamp):
Ensure `erc-stamp' is loaded.
* test/lisp/erc/erc-scenarios-match.el
(erc-scenarios-match--stamp-left-current-nick,
erc-scenarios-match--invisible-stamp): Use `default-value' for
`erc-insert-modify-hook' in ordering assertion.
(erc-scenarios-match--find-bol, erc-scenarios-match--find-eol): Remove
unused assertion helper functions.
(erc-scenarios-match--stamp-right-fools-invisible): Remove misplaced
ERT tag from function and use utility to find message bounds.
(erc-scenarios-match--stamp-right-fools-invisible): Use real utility
from main library to find message end.
(erc-scenarios-match--fill-wrap-stamp-dedented-p): New assertion
utility function.
(erc-scenarios-match--hide-fools/stamp-both/fill-wrap) New test.
(erc-scenarios-match--hide-fools/stamp-both/fill-wrap/speak): New
test.
(erc-scenarios-match--stamp-both-invisible-fill-static): Expect
`erc-cmd' at beginning of inserted message's filled line, even if the
line starts with white space.  Also, add new function parameter
`assert-ds', a callback to run when visiting the second date stamp,
which is followed by a hidden message.  In the test of the same name,
expect the date stamp's invisibility interval to begin at the newline
after the previous message and to not contain any existing
invisibility props, namely, those belonging to the subsequent hidden
"fools" message.  Also use shortened "metadata" text prop names.
(erc-scenarios-match--stamp-both-invisible-fill-static--nooffset):
Expect the date stamp's invisibility interval to match its field's
instead of starting and ending sooner.
* test/lisp/erc/erc-stamp-tests.el: Put well-known metadata prop at
the start of the message.
* test/lisp/erc/erc-tests.el (erc--refresh-prompt): Prevent modules
from mutating hooks.
(erc--order-text-properties-from-hash, erc--check-msg-prop): New
tests.
* test/lisp/erc/resources/fill/snapshots/merge-01-start.eld: Update
test data.
* test/lisp/erc/resources/fill/snapshots/merge-02-right.eld: Update
test data.
* test/lisp/erc/resources/fill/snapshots/merge-wrap-01.eld: Update.
* test/lisp/erc/resources/fill/snapshots/monospace-01-start.eld:
Update.
* test/lisp/erc/resources/fill/snapshots/monospace-02-right.eld:
Update.
* test/lisp/erc/resources/fill/snapshots/monospace-03-left.eld:
Update.
* test/lisp/erc/resources/fill/snapshots/monospace-04-reset.eld:
Update.
* test/lisp/erc/resources/fill/snapshots/spacing-01-mono.eld: Update.
* test/lisp/erc/resources/fill/snapshots/stamps-left-01.eld: Update.
* test/lisp/erc/resources/match/fools/fill-wrap.eld: New file.
(Bug#60936)