bug#44981: 28.0.50; Restore nnimap-split-download-body?

["Basil L. Contovounesios" <contovob@tcd.ie>]

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Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> I'm not sure why spam.el would need to work on the default value of
> `nnimap-split-download-body'. If spam.el determines that widening is
> needed, it's going to download message bodies across the board anyway.
> The only reason to preserve the user's own customization would be if the
> user later unloaded spam.el -- then it should restore the previous
> value. But how often would that actually be useful?
>
> In principle, TRT would be to have spam.el let-bind a variable around
> the splitting process. But I don't think the code is set up that way:
> all the spam.el stuff happens "inside" the splitting process, not around
> it.

How about the attached kludgy but conservative dance?

-- 
Basil


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From 9792b97faf4e5b1dc22e58d99806ec17a9fd7985 Mon Sep 17 00:00:00 2001
From: "Basil L. Contovounesios" <contovob@tcd.ie>
Date: Sat, 5 Dec 2020 15:28:35 +0000
Subject: [PATCH] Stop using deprecated nnimap variable in spam.el

* lisp/gnus/nnimap.el (nnimap--split-download-body): New variable.
(nnimap-fetch-inbox): Use it in conjunction with
nnimap-split-download-body.
* lisp/gnus/spam.el: Don't load nnimap.el at compile time for a
dynamic variable.
(spam-setup-widening): Rather than unconditionally set deprecated
nnimap-split-download-body-default, set nnimap--split-download-body
to recognizable non-nil value only if it is nil (bug#44981).
(spam-teardown-widening): Undo this if nnimap--split-download-body
still holds the recognizable value.
(spam-unload-hook): Call spam-teardown-widening to revert any change
to the value of nnimap--split-download-body.
---
 lisp/gnus/nnimap.el |  6 +++++-
 lisp/gnus/spam.el   | 26 +++++++++++++++++---------
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/lisp/gnus/nnimap.el b/lisp/gnus/nnimap.el
index a860333066..c8b700ebcc 100644
--- a/lisp/gnus/nnimap.el
+++ b/lisp/gnus/nnimap.el
@@ -157,6 +157,9 @@ nnimap-split-download-body
   :version "28.1"
   :type 'boolean)
 
+(defvar nnimap--split-download-body nil
+  "Like `nnimap-split-download-body', but for internal use.")
+
 (defvar nnimap-process nil)
 
 (defvar nnimap-status-string "")
@@ -2108,7 +2111,8 @@ nnimap-fetch-inbox
 		 "BODY.PEEK"
 	       "RFC822.PEEK"))
 	    (cond
-	     (nnimap-split-download-body
+             ((or nnimap-split-download-body
+                  nnimap--split-download-body)
 	      "[]")
 	     ((nnimap-ver4-p)
 	      "[HEADER]")
diff --git a/lisp/gnus/spam.el b/lisp/gnus/spam.el
index 96a7da2313..e74aef3efe 100644
--- a/lisp/gnus/spam.el
+++ b/lisp/gnus/spam.el
@@ -44,12 +44,9 @@
 ;;; for the definitions of group content classification and spam processors
 (require 'gnus)
 
-(eval-when-compile (require 'hashcash))
-
-;; for nnimap-split-download-body-default
-(eval-when-compile (require 'nnimap))
-
-(eval-when-compile (require 'cl-lib))
+(eval-when-compile
+  (require 'cl-lib)
+  (require 'hashcash))
 
 ;; autoload query-dig
 (autoload 'query-dig "dig")
@@ -1228,10 +1225,20 @@ spam-generic-score
 
 ;;{{{ set up widening, processor checks
 
-;;; set up IMAP widening if it's necessary
+(defconst spam--widened (list ())
+  "Unique value identifying changes to `nnimap--split-download-body'.")
+
 (defun spam-setup-widening ()
-  (when (spam-widening-needed-p)
-    (setq nnimap-split-download-body-default t)))
+  "Set up IMAP widening if it's necessary."
+  (and (boundp 'nnimap--split-download-body)
+       (not nnimap--split-download-body)
+       (spam-widening-needed-p)
+       (setq nnimap--split-download-body spam--widened)))
+
+(defun spam-teardown-widening ()
+  "Tear down IMAP widening."
+  (when (eq (bound-and-true-p nnimap--split-download-body) spam--widened)
+    (setq nnimap--split-download-body nil)))
 
 (defun spam-widening-needed-p (&optional force-symbols)
   (let (found)
@@ -2865,6 +2872,7 @@ spam-initialize
 (defun spam-unload-hook ()
   "Uninstall the spam.el hooks."
   (interactive)
+  (spam-teardown-widening)
   (remove-hook 'gnus-save-newsrc-hook 'spam-maybe-spam-stat-save)
   (remove-hook 'gnus-get-top-new-news-hook 'spam-maybe-spam-stat-load)
   (remove-hook 'gnus-startup-hook 'spam-maybe-spam-stat-load)
-- 
2.29.2