mu4e: Improve personal-address handling

Make mu4e-personal-address-p safe for being called with nil.

Upgrade code that used mu4e-user-mail-address-p to
mu4e-personal-address-p.

Update docs.

Add some more helpers to mu4e-message, and avoid some byte-compiler
warnings.

mu4e/mu4e-headers.el

@@ -608,7 +608,7 @@ cdr element the To: prefix.")
 otherwise ; show the from address; prefixed with the appropriate
 `mu4e-headers-from-or-to-prefix'."
   (let ((addr (cdr-safe (car-safe (mu4e-message-field msg :from)))))
-    (if (and addr (mu4e-user-mail-address-p addr))
+    (if (and addr (mu4e-personal-address-p addr))
         (concat (cdr mu4e-headers-from-or-to-prefix)
                 (mu4e~headers-contact-str (mu4e-message-field msg :to)))
       (concat (car mu4e-headers-from-or-to-prefix)

mu4e/mu4e-message.el

@@ -31,6 +31,11 @@
 (require 'flow-fill)
 (require 'shr)
 
+(declare-function mu4e-error "mu4e-utils")
+(declare-function mu4e-warn  "mu4e-utils")
+(declare-function mu4e-personal-address-p "mu4e-utils")
+(declare-function mu4e-make-temp-file  "mu4e-utils")
+
 (defvar mu4e~view-message)
 (defvar shr-inhibit-images)
 
@@ -287,6 +292,19 @@ cell that matched, or nil."
   (cl-find-if (lambda (cell) (mu4e-personal-address-p (cdr cell)))
                 (mu4e-message-field msg cfield)))
 
+(defun mu4e-message-sent-by-me (msg)
+  "Is this message (to be) sent by me?
+Checks if the from field matches user's personal addresses."
+  (mu4e-message-contact-field-matches-me msg :from))
+
+(defun mu4e-message-personal-p (msg)
+  "Does message have user's personal address in any of the
+contact fields?"
+  (cl-some
+   (lambda (field)
+     (mu4e-message-contact-field-matches-me msg field))
+   '(:from :to :cc :bcc)))
+
 (defsubst mu4e-message-part-field  (msgpart field)
   "Get some FIELD from MSGPART.
 A part would look something like:

mu4e/mu4e-utils.el

@@ -68,14 +68,15 @@
 Evaluate to nil if ADDR matches any of the personal addresses.
 Uses (mu4e-personal-addresses) for the addresses with both the plain
 addresses and /regular expressions/."
-  (seq-find
-   (lambda (m)
-     (if (string-match "/\\(.*\\)/" m)
-         (let ((rx (match-string 1 m))
-               (case-fold-search t))
-           (if (string-match rx addr) t nil))
+  (when addr
+    (seq-find
+     (lambda (m)
+       (if (string-match "/\\(.*\\)/" m)
+           (let ((rx (match-string 1 m))
+                 (case-fold-search t))
+             (if (string-match rx addr) t nil))
          (eq t (compare-strings addr nil nil m nil nil 'case-insensitive))))
-   (mu4e-personal-addresses)))
+     (mu4e-personal-addresses))))
 
 (define-obsolete-function-alias 'mu4e-user-mail-address-p
   'mu4e-personal-address-p "1.5.5")

mu4e/mu4e-view.el

@@ -270,7 +270,7 @@ found."
           (:from-or-to
            (let* ((from (mu4e-message-field msg :from))
                   (from (and from (cdar from))))
-             (if (mu4e-user-mail-address-p from)
+             (if (mu4e-personal-address-p from)
                  (mu4e~view-construct-contacts-header msg :to)
                (mu4e~view-construct-contacts-header msg :from))))
           ;; date

mu4e/mu4e.texi

@@ -2766,8 +2766,7 @@ message. An example should clarify this:
       ((mu4e-message-contact-field-matches msg :to
 	 "mu-discuss@@googlegroups.com")
 	"/mu")
-      ;; messages sent directly to me go to /archive
-      ;; also `mu4e-user-mail-address-p' can be used
+      ;; messages sent directly to some spefic address me go to /private
       ((mu4e-message-contact-field-matches msg :to "me@@example.com")
 	"/private")
       ;; messages with football or soccer in the subject go to /football
@@ -2775,9 +2774,7 @@ message. An example should clarify this:
 	 (mu4e-message-field msg :subject))
 	"/football")
       ;; messages sent by me go to the sent folder
-      ((find-if
-	 (lambda (addr)
-	   (mu4e-message-contact-field-matches msg :from addr))
+      ((mu4e-message-sent-by-me msg
 	 (mu4e-personal-addresses))
 	mu4e-sent-folder)
       ;; everything else goes to /archive