Feature: Optionally disable todo propagation to parents/children (Issue #954)

taskwiki integrates vimwiki with taskwarrior, and in doing so changes
the semantics of checkboxes a bit:

    * [ ] Install Taskwiki   |   pending task
    * [X] Install Taskwiki   |   completed task
    * [D] Install Taskwiki   |   deleted task
    * [S] Install Taskwiki   |   started task
    * [W] Install Taskwiki   |   waiting task

It's still desirable for vimwiki to automatically insert `* [ ]` on
`i_<CR>`, `o` and `O` and to syntax highlight all these five as
checkboxes, so I have this in my .vimrc:

    let g:vimwiki_listsym_rejected = 'D'
    let g:vimwiki_listsyms = ' WSX'

but it results in undesirable behaviour with task hierarchies: when I
add a new subtask (using `i_<CR>`, `o` or `O`)
or mark a subtask done, the parent's checkbox is updated to reflect its
overall completion, to one of ` `, `W`, `S` or `X`, depending on
subtasks completion. This makes little sense in taskwiki. One usually
doesn't want to touch the "parent" task in taskwarrior until the
"subtasks" are done. Setting

    let g:vimwiki_listsym_rejected = 'W'
    let g:vimwiki_listsyms = ' SX'

results in slightly less illogical behaviour, but it still assumes that
(1) all subtasks are visible (not necessarily true in taskwiki) and
(2) that it's a parent/subtask relationship, not a dependency
relationship (not true in taskwarrior, questionable in taskwiki).

This commit adds an option to disable this behaviour.

autoload/vimwiki/lst.vim

@@ -800,6 +800,10 @@ function! s:set_state_plus_children(item, new_rate, ...) abort
     call s:set_state(a:item, a:new_rate)
   endif
 
+  if vimwiki#vars#get_wikilocal('listsyms_propagate') == 0
+    return
+  endif
+
   let all_children_are_done = 1
   let all_children_are_rejected = 1
 
@@ -867,7 +871,7 @@ endfunction
 "updates the symbol of a checkboxed item according to the symbols of its
 "children
 function! s:update_state(item) abort
-  if a:item.type == 0 || a:item.cb ==? ''
+  if a:item.type == 0 || a:item.cb ==? '' || vimwiki#vars#get_wikilocal('listsyms_propagate') == 0
     return
   endif
 

autoload/vimwiki/vars.vim

@@ -506,6 +506,7 @@ function! s:get_default_wikilocal() abort
         \ 'list_margin': {'type': type(0), 'default': -1, 'min': -1},
         \ 'listsym_rejected': {'type': type(''), 'default': vimwiki#vars#get_global('listsym_rejected')},
         \ 'listsyms': {'type': type(''), 'default': vimwiki#vars#get_global('listsyms')},
+        \ 'listsyms_propagate': {'type': type(0), 'default': 1},
         \ 'markdown_link_ext': {'type': type(0), 'default': 0, 'min': 0, 'max': 1},
         \ 'maxhi': {'type': type(0), 'default': 0, 'min': 0, 'max': 1},
         \ 'name': {'type': type(''), 'default': ''},

doc/vimwiki.txt

@@ -1880,9 +1880,10 @@ parent items: >
    * [ ] Add highlighting to list item boxes.
    * [ ] Add [ ] to the next list item created using o, O or <CR>.
 
-Parent items should change when their child items change. If not, use
-|vimwiki_glr|. The symbol between [ ] depends on the percentage of toggled
-child items (see also |vimwiki-listsyms|): >
+Parent items should change when their child items change unless disabled via
+|vimwiki-option-listsyms_propagate|. If not, use |vimwiki_glr|. The symbol
+between [ ] depends on the percentage of toggled child items (see also
+|vimwiki-listsyms|): >
     [ ] -- 0%
     [.] -- 1-33%
     [o] -- 34-66%
@@ -2674,6 +2675,16 @@ You can set it to a more fancy symbol like this:
    let g:vimwiki_list = [{'path': '~/path/', 'listsym_rejected' = '✗'}]
 
 
+*vimwiki-option-listsyms_propagate*
+------------------------------------------------------------------------------
+Key                 Default value     Values~
+listsyms_propagate  1                 0, 1
+
+Description~
+Set this option to 0 to disable propagation of todo list item status to
+parents and children.
+
+
 *vimwiki-option-auto_tags*
 ------------------------------------------------------------------------------
 Key             Default value     Values~
@@ -3831,6 +3842,7 @@ Contributors and their Github usernames in roughly chronological order:
     - Benney Au (@chinwobble)
     - David Sierra DiazGranados (@davidsierradz)
     - Daniel Moura (@dmouraneto)
+    - Tomáš Janoušek (@liskin)
 
 ==============================================================================
 16. Changelog                                              *vimwiki-changelog*
@@ -3842,6 +3854,8 @@ http://code.google.com/p/vimwiki/issues/list. They may be accessible from
 https://github.com/vimwiki-backup/vimwiki/issues.
 
 New:~
+    * Feature: #954: Add option |vimwiki-option-listsyms_propagate| to disable
+      todo propagation to parents/children
     * Issue #1009: |foldmethod| syntax works for markdown (|g:vimwiki_folding|)
       Also the VimwikiHeader1Folding (1..60 regions support end-of-file `/\%$`
       as end maker

test/list_update_nopropagate.vader

@@ -0,0 +1,87 @@
+# Task list update, propagation disabled
+
+Given vimwiki (Sample nested list, vimwiki syntax):
+  * [ ] Top Level
+    * [ ] Child 1
+    * [ ] Child 2
+    * [ ] Child 3
+
+Execute (Set syntax to default):
+  set sw=2
+  call SetSyntax('default')
+  call vimwiki#vars#set_wikilocal('listsyms_propagate', 0)
+
+Do (Toggle top-level):
+  \<C-Space>
+
+Expect vimwiki (Only top updated):
+  * [X] Top Level
+    * [ ] Child 1
+    * [ ] Child 2
+    * [ ] Child 3
+
+Do (Toggle child 1):
+  j
+  \<C-Space>
+
+Expect vimwiki (Only child 1 updated):
+  * [ ] Top Level
+    * [X] Child 1
+    * [ ] Child 2
+    * [ ] Child 3
+
+Do (Toggle all children):
+  j
+  \<C-Space>
+  j
+  \<C-Space>
+  j
+  \<C-Space>
+
+Expect vimwiki (Only children updated):
+  * [ ] Top Level
+    * [X] Child 1
+    * [X] Child 2
+    * [X] Child 3
+
+Given vimwiki (Deeply nested list, vimwiki syntax):
+  * [ ] Top Level
+    * [ ] Child 1
+      * [X] Child 2
+
+Do (Indent child 2):
+  jj
+  a\<C-D>
+
+Expect vimwiki (Child 2 indent changed, checkmarks unchanged):
+  * [ ] Top Level
+    * [ ] Child 1
+    * [X] Child 2
+
+Do (Add child 3):
+  jj
+  o
+  Child 3
+
+Expect vimwiki (Child 3 added, checkmarks unchanged):
+  * [ ] Top Level
+    * [ ] Child 1
+      * [X] Child 2
+      * [ ] Child 3
+
+Do (Add and indent child 3):
+  jj
+  o
+  \<C-T>
+  Child 3
+
+Expect vimwiki (Child 3 added, checkmarks unchanged):
+  * [ ] Top Level
+    * [ ] Child 1
+      * [X] Child 2
+        * [ ] Child 3
+
+Execute (Clean):
+  set sw&
+
+# vim: sw=2:foldlevel=30:foldmethod=indent:

test/map.vader

@@ -7,6 +7,7 @@
 ##################
 
 Execute (VimwikiIndex):
+  call SetSyntax('markdown')
   VimwikiIndex 2
   AssertEqual 1, vimwiki#vars#get_bufferlocal('wiki_nr')
   AssertEqual 'vimwiki', &filetype