shada: Also store last search direction

Note: it looks like viminfo files do not store search direction intentionally.
After reading viminfo file search direction was considered to be “forward”.

Note 2: all files created on earlier Neovim version will automatically receive
“forward” direction.

Fixes #3580

runtime/autoload/shada.vim

@@ -43,7 +43,8 @@ call map(copy(s:SHADA_ENTRY_NAMES),
 " Only contains data for entries which are represented as mappings, except for 
 " the header.
 let s:SHADA_MAP_ENTRIES = {
-  \'search_pattern': ['sp', 'sh', 'ss', 'sm', 'sc', 'sl', 'se', 'so', 'su'],
+  \'search_pattern': ['sp', 'sh', 'ss', 'sb', 'sm', 'sc', 'sl', 'se', 'so',
+  \                   'su'],
   \'register': ['n', 'rc', 'rw', 'rt'],
   \'global_mark': ['n', 'f', 'l', 'c'],
   \'local_mark': ['f', 'n', 'l', 'c'],
@@ -134,6 +135,7 @@ let s:SHADA_STANDARD_KEYS = {
   \'ss': ['is :s pattern', 'boolean', g:msgpack#false],
   \'sh': ['v:hlsearch value', 'boolean', g:msgpack#false],
   \'sp': ['pattern', 'bin', s:SHADA_REQUIRED],
+  \'sb': ['search backward', 'boolean', g:msgpack#false],
   \'rt': ['type', 'regtype', s:SHADA_ENUMS.regtype.CHARACTERWISE],
   \'rw': ['block width', 'uint', 0],
   \'rc': ['contents', 'binarray', s:SHADA_REQUIRED],

runtime/doc/starting.txt

@@ -1232,6 +1232,8 @@ exactly four MessagePack objects:
                                               With |shada-h| or 'nohlsearch' 
                                               this key is always false.
                        sp   Binary   N/A      Actual pattern.  Required.
+                       sb   Boolean  false    True if search direction is 
+                                              backward.
                        *    any      none     Other keys are allowed for 
                                               compatibility reasons, see 
                                               |shada-compatibility|.

runtime/doc/vim_diff.txt

@@ -117,6 +117,7 @@ Additional differences:
   |shada-error-handling|
 - Vim keeps no timestamps at all, neither in viminfo file nor in the instance 
   itself.
+- ShaDa file keeps search direction (|v:searchforward|), viminfo does not.
 
 ==============================================================================
 4. New Features						     *nvim-features-new*

src/nvim/search.c

@@ -4623,6 +4623,7 @@ void set_search_pattern(const SearchPattern pat)
 {
   free_spat(&spats[0]);
   memcpy(&(spats[0]), &pat, sizeof(spats[0]));
+  set_vv_searchforward();
 }
 
 /// Set last substitute pattern

src/nvim/shada.c

@@ -98,6 +98,7 @@ KHASH_SET_INIT_STR(strset)
 #define SEARCH_KEY_HIGHLIGHTED "sh"
 #define SEARCH_KEY_OFFSET "so"
 #define SEARCH_KEY_PAT "sp"
+#define SEARCH_KEY_BACKWARD "sb"
 
 #define REG_KEY_TYPE "rt"
 #define REG_KEY_WIDTH "rw"
@@ -263,6 +264,7 @@ typedef struct {
       bool is_last_used;
       bool is_substitute_pattern;
       bool highlighted;
+      bool search_backward;
       char *pat;
       dict_T *additional_data;
     } search_pattern;
@@ -455,6 +457,7 @@ static const ShadaEntry sd_default_values[] = {
           .is_last_used = true,
           .is_substitute_pattern = false,
           .highlighted = false,
+          .search_backward = false,
           .pat = NULL,
           .additional_data = NULL),
   DEF_SDE(SubString, sub_string, .sub = NULL, .additional_elements = NULL),
@@ -1338,6 +1341,7 @@ static void shada_read(ShaDaReadDef *const sd_reader, const int flags)
           .magic = cur_entry.data.search_pattern.magic,
           .no_scs = !cur_entry.data.search_pattern.smartcase,
           .off = {
+            .dir = cur_entry.data.search_pattern.search_backward ? '?' : '/',
             .line = cur_entry.data.search_pattern.has_line_offset,
             .end = cur_entry.data.search_pattern.place_cursor_at_end,
             .off = cur_entry.data.search_pattern.offset,
@@ -1754,6 +1758,7 @@ static bool shada_pack_entry(msgpack_packer *const packer,
           + ONE_IF_NOT_DEFAULT(entry, search_pattern.is_substitute_pattern)
           + ONE_IF_NOT_DEFAULT(entry, search_pattern.highlighted)
           + ONE_IF_NOT_DEFAULT(entry, search_pattern.offset)
+          + ONE_IF_NOT_DEFAULT(entry, search_pattern.search_backward)
           // finally, additional data:
           + (size_t) (
               entry.data.search_pattern.additional_data
@@ -1780,6 +1785,7 @@ static bool shada_pack_entry(msgpack_packer *const packer,
       PACK_BOOL(entry, SEARCH_KEY_PLACE_CURSOR_AT_END, place_cursor_at_end);
       PACK_BOOL(entry, SEARCH_KEY_IS_SUBSTITUTE_PATTERN, is_substitute_pattern);
       PACK_BOOL(entry, SEARCH_KEY_HIGHLIGHTED, highlighted);
+      PACK_BOOL(entry, SEARCH_KEY_BACKWARD, search_backward);
       if (!CHECK_DEFAULT(entry, search_pattern.offset)) {
         PACK_STATIC_STR(SEARCH_KEY_OFFSET);
         msgpack_pack_int64(spacker, entry.data.search_pattern.offset);
@@ -2581,6 +2587,7 @@ static ShaDaWriteResult shada_write(ShaDaWriteDef *const sd_writer,
                               && search_highlighted), \
               .pat = (char *) pat.pat, \
               .additional_data = pat.additional_data, \
+              .search_backward = (!is_sub && pat.off.dir == '?'), \
             } \
           } \
         } \
@@ -3632,6 +3639,9 @@ shada_read_next_item_start:
         else
           BOOLEAN_KEY("search pattern", SEARCH_KEY_HIGHLIGHTED,
                       entry->data.search_pattern.highlighted)
+        else
+          BOOLEAN_KEY("search pattern", SEARCH_KEY_BACKWARD,
+                      entry->data.search_pattern.search_backward)
         else
           INTEGER_KEY("search pattern", SEARCH_KEY_OFFSET,
                       entry->data.search_pattern.offset)

test/functional/plugin/shada_spec.lua

@@ -209,6 +209,7 @@ describe('In autoload/shada.vim', function()
         '  + rc   contents             ["abc", "def"]',
         '  + rt   type                 CHARACTERWISE',
         '  + rw   block width          10',
+        '  + sb   search backward      TRUE',
         '  + sc   smartcase value      FALSE',
         '  + se   place cursor at end  TRUE',
         '  + sh   v:hlsearch value     TRUE',
@@ -223,6 +224,7 @@ describe('In autoload/shada.vim', function()
         'sc': {'_TYPE': v:msgpack_types.boolean, '_VAL': 0},
         'sl': {'_TYPE': v:msgpack_types.boolean, '_VAL': 0},
         'se': {'_TYPE': v:msgpack_types.boolean, '_VAL': 1},
+        'sb': {'_TYPE': v:msgpack_types.boolean, '_VAL': 1},
         'so': 10,
         'su': {'_TYPE': v:msgpack_types.boolean, '_VAL': 0},
         'ss': {'_TYPE': v:msgpack_types.boolean, '_VAL': 1},
@@ -308,6 +310,7 @@ describe('In autoload/shada.vim', function()
         '  + sp   pattern              "abc"',
         '  + sh   v:hlsearch value     FALSE',
         '  + ss   is :s pattern        FALSE',
+        '  + sb   search backward      FALSE',
         '  + sm   magic value          TRUE',
         '  + sc   smartcase value      FALSE',
         '  + sl   has line offset      FALSE',
@@ -323,6 +326,7 @@ describe('In autoload/shada.vim', function()
         '  + sp   pattern              "abc"',
         '  + sh   v:hlsearch value     FALSE',
         '  + ss   is :s pattern        FALSE',
+        '  + sb   search backward      FALSE',
         '  + sm   magic value          TRUE',
         '  + sc   smartcase value      FALSE',
         '  + sl   has line offset      FALSE',
@@ -344,6 +348,7 @@ describe('In autoload/shada.vim', function()
         '  + sp   pattern              "abc"',
         '  + sh   v:hlsearch value     FALSE',
         '  + ss   is :s pattern        FALSE',
+        '  + sb   search backward      FALSE',
         '  + sm   magic value          TRUE',
         '  + sc   smartcase value      FALSE',
         '  + sl   has line offset      FALSE',
@@ -354,6 +359,7 @@ describe('In autoload/shada.vim', function()
         'sp': 'abc',
         'sh': {'_TYPE': v:msgpack_types.boolean, '_VAL': 0},
         'ss': {'_TYPE': v:msgpack_types.boolean, '_VAL': 0},
+        'sb': {'_TYPE': v:msgpack_types.boolean, '_VAL': 0},
         'sm': {'_TYPE': v:msgpack_types.boolean, '_VAL': 1},
         'sc': {'_TYPE': v:msgpack_types.boolean, '_VAL': 0},
         'sl': {'_TYPE': v:msgpack_types.boolean, '_VAL': 0},
@@ -367,6 +373,7 @@ describe('In autoload/shada.vim', function()
         '  # Required key missing: sp',
         '  + sh   v:hlsearch value     FALSE',
         '  + ss   is :s pattern        FALSE',
+        '  + sb   search backward      FALSE',
         '  + sm   magic value          TRUE',
         '  + sc   smartcase value      FALSE',
         '  + sl   has line offset      FALSE',
@@ -381,6 +388,7 @@ describe('In autoload/shada.vim', function()
         '  + sp   pattern              ""',
         '  + sh   v:hlsearch value     TRUE',
         '  + ss   is :s pattern        TRUE',
+        '  + sb   search backward      TRUE',
         '  + sm   magic value          FALSE',
         '  + sc   smartcase value      TRUE',
         '  + sl   has line offset      TRUE',
@@ -391,6 +399,7 @@ describe('In autoload/shada.vim', function()
         'sp': '',
         'sh': {'_TYPE': v:msgpack_types.boolean, '_VAL': 1},
         'ss': {'_TYPE': v:msgpack_types.boolean, '_VAL': 1},
+        'sb': {'_TYPE': v:msgpack_types.boolean, '_VAL': 1},
         'sm': {'_TYPE': v:msgpack_types.boolean, '_VAL': 0},
         'sc': {'_TYPE': v:msgpack_types.boolean, '_VAL': 1},
         'sl': {'_TYPE': v:msgpack_types.boolean, '_VAL': 1},
@@ -408,6 +417,8 @@ describe('In autoload/shada.vim', function()
         '  # Expected boolean',
         '  + ss   is :s pattern        0',
         '  # Expected boolean',
+        '  + sb   search backward      0',
+        '  # Expected boolean',
         '  + sm   magic value          0',
         '  # Expected boolean',
         '  + sc   smartcase value      0',
@@ -423,6 +434,7 @@ describe('In autoload/shada.vim', function()
         'sp': 0,
         'sh': 0,
         'ss': 0,
+        'sb': 0,
         'sm': 0,
         'sc': 0,
         'sl': 0,

test/functional/shada/errors_spec.lua

@@ -124,6 +124,11 @@ describe('ShaDa error handling', function()
     eq('Vim(rshada):E575: Error while reading ShaDa file: search pattern entry at position 0 has sc key value which is not a boolean', exc_exec(sdrcmd()))
   end)
 
+  it('fails on search pattern item with NIL search_backward key value', function()
+    wshada('\002\000\009\130\162sX\192\162sb\192')
+    eq('Vim(rshada):E575: Error while reading ShaDa file: search pattern entry at position 0 has sb key value which is not a boolean', exc_exec(sdrcmd()))
+  end)
+
   it('fails on search pattern item with NIL has_line_offset key value', function()
     wshada('\002\000\009\130\162sX\192\162sl\192')
     eq('Vim(rshada):E575: Error while reading ShaDa file: search pattern entry at position 0 has sl key value which is not a boolean', exc_exec(sdrcmd()))

test/functional/shada/history_spec.lua

@@ -107,14 +107,32 @@ describe('ShaDa support code', function()
   end)
 
   it('dumps and loads last search pattern with offset', function()
-    funcs.setline('.', {'foo', 'bar'})
+    meths.set_option('wrapscan', false)
+    funcs.setline('.', {'foo', 'bar--'})
     nvim_feed('gg0/a/e+1\n')
     eq({0, 2, 3, 0}, funcs.getpos('.'))
     nvim_command('wshada')
     reset()
-    funcs.setline('.', {'foo', 'bar'})
+    meths.set_option('wrapscan', false)
+    funcs.setline('.', {'foo', 'bar--'})
     nvim_feed('gg0n')
     eq({0, 2, 3, 0}, funcs.getpos('.'))
+    eq(1, meths.get_vvar('searchforward'))
+  end)
+
+  it('dumps and loads last search pattern with offset and backward direction',
+  function()
+    meths.set_option('wrapscan', false)
+    funcs.setline('.', {'foo', 'bar--'})
+    nvim_feed('G$?a?e+1\n')
+    eq({0, 2, 3, 0}, funcs.getpos('.'))
+    nvim_command('wshada')
+    reset()
+    meths.set_option('wrapscan', false)
+    funcs.setline('.', {'foo', 'bar--'})
+    nvim_feed('G$n')
+    eq({0, 2, 3, 0}, funcs.getpos('.'))
+    eq(0, meths.get_vvar('searchforward'))
   end)
 
   it('saves v:hlsearch=1', function()