vim-patch:9.0.0861: solution for "!!sort" in closed fold is not optimal (#21027)

Problem:    Solution for "!!sort" in closed fold is not optimal.
Solution:   Use a different range instead of the subtle difference in handling
            a range with an offset. (issue vim/vim#11487)

https://github.com/vim/vim/commit/9954dc39ea090cee6bf41c888c41e60d9f52c3b8

Co-authored-by: Bram Moolenaar <Bram@vim.org>

4 files changed, 104 insertions, 20 deletions

diff --git a/runtime/doc/cmdline.txt b/runtime/doc/cmdline.txt
index c7ffa920b6..b4923b0d70 100644
--- a/runtime/doc/cmdline.txt
+++ b/runtime/doc/cmdline.txt
@@ -690,7 +690,9 @@ Line numbers may be specified with:		*:range* *{address}*
 	'T		position of mark T (uppercase); when the mark is in
 			another file it cannot be used in a range
 	/{pattern}[/]	the next line where {pattern} matches	  *:/*
+				also see |:range-pattern| below
 	?{pattern}[?]	the previous line where {pattern} matches *:?*
+				also see |:range-pattern| below
 	\/		the next line where the previously used search
 			pattern matches
 	\?		the previous line where the previously used search
@@ -698,11 +700,49 @@ Line numbers may be specified with:		*:range* *{address}*
 	\&		the next line where the previously used substitute
 			pattern matches
 
+						*:range-offset*
 Each may be followed (several times) by '+' or '-' and an optional number.
 This number is added or subtracted from the preceding line number.  If the
 number is omitted, 1 is used.  If there is nothing before the '+' or '-' then
 the current line is used.
-
+						*:range-closed-fold*
+When a line number after the comma is in a closed fold it is adjusted to the
+last line of the fold, thus the whole fold is included.
+
+When a number is added this is done after the adjustment to the last line of
+the fold.  This means these lines are additionally included in the range.  For
+example: >
+   :3,4+2print
+On this text:
+	1 one ~
+	2 two ~
+	3 three ~
+	4 four FOLDED ~
+	5 five FOLDED ~
+	6 six ~
+	7 seven ~
+	8 eight ~
+Where lines four and five are a closed fold, ends up printing lines 3 to 7.
+The 7 comes from the "4" in the range, which is adjusted to the end of the
+closed fold, which is 5, and then the offset 2 is added.
+
+An example for subtracting (which isn't very useful): >
+   :2,4-1print
+On this text:
+	1 one ~
+	2 two ~
+	3 three FOLDED~
+	4 four FOLDED ~
+	5 five FOLDED ~
+	6 six FOLDED ~
+	7 seven ~
+	8 eight ~
+Where lines three to six are a closed fold, ends up printing lines 2 to 6.
+The 6 comes from the "4" in the range, which is adjusted to the end of the
+closed fold, which is 6, and then 1 is subtracted, then this is still in the
+closed fold and the last line of that fold is used, which is 6.
+
+							*:range-pattern*
 The "/" and "?" after {pattern} are required to separate the pattern from
 anything that follows.
 
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index f4100272e1..b875aafaad 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -3224,8 +3224,6 @@ static linenr_T get_address(exarg_T *eap, char **ptr, cmd_addr_T addr_type, int
   char *cmd = skipwhite(*ptr);
   linenr_T lnum = MAXLNUM;
   do {
-    const int base_char = (uint8_t)(*cmd);
-
     switch (*cmd) {
     case '.':                               // '.' - Cursor position
       cmd++;
@@ -3502,16 +3500,10 @@ static linenr_T get_address(exarg_T *eap, char **ptr, cmd_addr_T addr_type, int
       } else if (addr_type == ADDR_LOADED_BUFFERS || addr_type == ADDR_BUFFERS) {
         lnum = compute_buffer_local_count(addr_type, lnum, (i == '-') ? -1 * n : n);
       } else {
-        // Relative line addressing: need to adjust for closed folds
-        // after the first address.
-        // Subtle difference: "number,+number" and "number,-number"
-        // adjusts to end of closed fold before adding/subtracting,
-        // while "number,.+number" adjusts to end of closed fold after
-        // adding to make "!!" expanded into ".,.+N" work correctly.
-        bool adjust_for_folding = addr_type == ADDR_LINES
-                                  && (i == '-' || i == '+')
-                                  && address_count >= 2;
-        if (adjust_for_folding && (i == '-' || base_char != '.')) {
+        // Relative line addressing: need to adjust for lines in a
+        // closed fold after the first address.
+        if (addr_type == ADDR_LINES && (i == '-' || i == '+')
+            && address_count >= 2) {
           (void)hasFolding(lnum, NULL, &lnum);
         }
         if (i == '-') {
@@ -3522,11 +3514,6 @@ static linenr_T get_address(exarg_T *eap, char **ptr, cmd_addr_T addr_type, int
             goto error;
           }
           lnum += n;
-          // ".+number" rounds up to the end of a closed fold after
-          // adding, so that ":!!sort" sorts one closed fold.
-          if (adjust_for_folding && base_char == '.') {
-            (void)hasFolding(lnum, NULL, &lnum);
-          }
         }
       }
     }
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 65fc42bc08..8656b4265d 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -5555,13 +5555,22 @@ static void op_colon(oparg_T *oap)
     } else {
       stuffnumReadbuff((long)oap->start.lnum);
     }
-    if (oap->end.lnum != oap->start.lnum) {
+
+    // When using !! on a closed fold the range ".!" works best to operate
+    // on, it will be made the whole closed fold later.
+    linenr_T endOfStartFold = oap->start.lnum;
+    (void)hasFolding(oap->start.lnum, NULL, &endOfStartFold);
+    if (oap->end.lnum != oap->start.lnum && oap->end.lnum != endOfStartFold) {
+      // Make it a range with the end line.
       stuffcharReadbuff(',');
       if (oap->end.lnum == curwin->w_cursor.lnum) {
         stuffcharReadbuff('.');
       } else if (oap->end.lnum == curbuf->b_ml.ml_line_count) {
         stuffcharReadbuff('$');
-      } else if (oap->start.lnum == curwin->w_cursor.lnum) {
+      } else if (oap->start.lnum == curwin->w_cursor.lnum
+                 // do not use ".+number" for a closed fold, it would count
+                 // folded lines twice
+                 && !hasFolding(oap->end.lnum, NULL, NULL)) {
         stuffReadbuff(".+");
         stuffnumReadbuff(oap->line_count - 1);
       } else {
diff --git a/src/nvim/testdir/test_fold.vim b/src/nvim/testdir/test_fold.vim
index 1ee9165308..1b979dbc03 100644
--- a/src/nvim/testdir/test_fold.vim
+++ b/src/nvim/testdir/test_fold.vim
@@ -72,6 +72,54 @@ func Test_address_fold()
   quit!
 endfunc
 
+func Test_address_offsets()
+  " check the help for :range-closed-fold
+  enew
+  call setline(1, [
+        \ '1 one',
+        \ '2 two',
+        \ '3 three',
+        \ '4 four FOLDED',
+        \ '5 five FOLDED',
+        \ '6 six',
+        \ '7 seven',
+        \ '8 eight',
+        \])
+  set foldmethod=manual
+  normal 4Gvjzf
+  3,4+2yank
+  call assert_equal([
+        \ '3 three',
+        \ '4 four FOLDED',
+        \ '5 five FOLDED',
+        \ '6 six',
+        \ '7 seven',
+        \ ], getreg(0,1,1))
+
+  enew!
+  call setline(1, [
+        \ '1 one',
+        \ '2 two',
+        \ '3 three FOLDED',
+        \ '4 four FOLDED',
+        \ '5 five FOLDED',
+        \ '6 six FOLDED',
+        \ '7 seven',
+        \ '8 eight',
+        \])
+  normal 3Gv3jzf
+  2,4-1yank
+  call assert_equal([
+        \ '2 two',
+        \ '3 three FOLDED',
+        \ '4 four FOLDED',
+        \ '5 five FOLDED',
+        \ '6 six FOLDED',
+        \ ], getreg(0,1,1))
+
+  bwipe!
+endfunc
+
 func Test_indent_fold()
     new
     call setline(1, ['', 'a', '    b', '    c'])