master d24ad50: MH-E: support Mailutils "folders +/"

[Stephen Gildea]

branch: master
commit d24ad504fcc342725febc187e17d6b69cc527b6b
Author: Stephen Gildea <stepheng+emacs@gildea.com>
Commit: Stephen Gildea <stepheng+emacs@gildea.com>

    MH-E: support Mailutils "folders +/"
    
    * lisp/mh-e/mh-utils.el (mh-sub-folders-parse):
    Support Mailutils style of "folders +/" output.
    * test/lisp/mh-e/mh-utils.el:
    Test "folders +/" with GNU Mailutils 3.13.91 and later.
---
 lisp/mh-e/mh-utils.el            |  7 +++++++
 test/lisp/mh-e/mh-utils-tests.el | 11 +++++++----
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/lisp/mh-e/mh-utils.el b/lisp/mh-e/mh-utils.el
index ad23bd1..b75025d 100644
--- a/lisp/mh-e/mh-utils.el
+++ b/lisp/mh-e/mh-utils.el
@@ -592,10 +592,14 @@ This function is a testable helper of 
`mh-sub-folders-actual'."
             (cl-incf start-pos))
           (let* ((name (buffer-substring start-pos has-pos))
                  (first-char (aref name 0))
+                 (second-char (and (length> name 1) (aref name 1)))
                  (last-char (aref name (1- (length name)))))
             (unless (member first-char '(?. ?# ?,))
               (when (and (equal last-char ?+) (equal name current-folder))
                 (setq name (substring name 0 (1- (length name)))))
+              ;; nmh outputs double slash in root folder, e.g., "//tmp"
+              (when (and (equal first-char ?/) (equal second-char ?/))
+                (setq name (substring name 1)))
               (push
                (cons name
                      (search-forward "(others)" (line-end-position) t))
@@ -605,6 +609,9 @@ This function is a testable helper of 
`mh-sub-folders-actual'."
     (when (stringp folder)
       (setq results (cdr results))
       (let ((folder-name-len (length (format "%s/" (substring folder 1)))))
+        (when (equal "+/" folder)
+          ;; folder "+/" includes a trailing slash
+          (cl-decf folder-name-len))
         (setq results (mapcar (lambda (f)
                                 (cons (substring (car f) folder-name-len)
                                       (cdr f)))
diff --git a/test/lisp/mh-e/mh-utils-tests.el b/test/lisp/mh-e/mh-utils-tests.el
index 8394920..f282a0b 100644
--- a/test/lisp/mh-e/mh-utils-tests.el
+++ b/test/lisp/mh-e/mh-utils-tests.el
@@ -121,10 +121,12 @@
   "Test `mh-sub-folders-parse' with root folder."
   (with-temp-buffer
     (insert "/+  has no messages.\n")
+    (insert "/   has no messages.\n")
     (insert "//nmh-style  has no messages.\n")
+    (insert "/mu-style  has no messages.\n")
     (should (equal
              (mh-sub-folders-parse "+/" "inbox+")
-             '(("nmh-style"))))))
+             '(("") ("nmh-style") ("mu-style"))))))
 
 
 ;; Folder names that are used by the following tests.
@@ -259,8 +261,8 @@ The tests use this method if no configured MH variant is 
found."
              "/abso-folder/food  has no messages."))
            (("folders" "-noheader" "-norecurse" "-nototal" "+/") .
             ("/+             has no messages ; (others)."
-             "//abso-folder  has no messages ; (others)."
-             "//tmp          has no messages ; (others)."))
+             "/abso-folder   has no messages ; (others)."
+             "/tmp           has no messages ; (others)."))
            ))
         (arglist (cons (file-name-base program) args)))
     (let ((response-list-cons (assoc arglist argument-responses)))
@@ -358,7 +360,8 @@ if `mh-test-utils-debug-mocks' is non-nil."
 Mailutils 3.5, 3.7, and 3.13 are known not to."
   (cond ((not (stringp variant)))       ;our mock handles it
         ((string-search "GNU Mailutils" variant)
-         nil)
+         (let ((mu-version (string-remove-prefix "GNU Mailutils " variant)))
+           (version<= "3.13.91" mu-version)))
         (t)))                           ;no other known failures