vim-patch:8.1.0235: more help tags that jump to the wrong location

Problem:    More help tags that jump to the wrong location.
Solution:   Add more exceptions and a table for "expr-" tags. (Hirohito
            Higashi)
https://github.com/vim/vim/commit/3bf5e6a4c8eb84b44437d6148428565d44783eed

2 files changed, 48 insertions, 10 deletions

diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index 8971c0c16c..7538e353c4 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -4688,7 +4688,8 @@ int find_help_tags(char_u *arg, int *num_matches, char_u ***matches, int keep_la
   static char *(mtable[]) = {"*", "g*", "[*", "]*",
                              "/*", "/\\*", "\"*", "**",
                              "/\\(\\)", "/\\%(\\)",
-                             "?", ":?", "-?", "?<CR>", "g?", "g?g?", "g??",
+                             "?", ":?", "?<CR>", "g?", "g?g?", "g??",
+                             "-?", "q?", "v_g?",
                              "/\\?", "/\\z(\\)", "\\=", ":s\\=",
                              "[count]", "[quotex]",
                              "[range]", ":[range]",
@@ -4698,26 +4699,40 @@ int find_help_tags(char_u *arg, int *num_matches, char_u ***matches, int keep_la
   static char *(rtable[]) = {"star", "gstar", "[star", "]star",
                              "/star", "/\\\\star", "quotestar", "starstar",
                              "/\\\\(\\\\)", "/\\\\%(\\\\)",
-                             "?", ":?", "-?", "?<CR>", "g?", "g?g?", "g??",
+                             "?", ":?", "?<CR>", "g?", "g?g?", "g??",
+                             "-?", "q?", "v_g?",
                              "/\\\\?", "/\\\\z(\\\\)", "\\\\=", ":s\\\\=",
                              "\\[count]", "\\[quotex]",
                              "\\[range]", ":\\[range]",
                              "\\[pattern]", "\\\\bar", "/\\\\%\\$",
                              "s/\\\\\\~", "s/\\\\U", "s/\\\\L",
                              "s/\\\\1", "s/\\\\2", "s/\\\\3", "s/\\\\9"};
+  static char *(expr_table[]) = {"!=?", "!~?", "<=?", "<?", "==?", "=~?",
+                                 ">=?", ">?", "is?", "isnot?"};
   int flags;
 
   d = IObuff;               /* assume IObuff is long enough! */
 
-  /*
-   * Recognize a few exceptions to the rule.	Some strings that contain '*'
-   * with "star".  Otherwise '*' is recognized as a wildcard.
-   */
-  for (i = (int)ARRAY_SIZE(mtable); --i >= 0; )
-    if (STRCMP(arg, mtable[i]) == 0) {
-      STRCPY(d, rtable[i]);
-      break;
+  if (STRNICMP(arg, "expr-", 5) == 0) {
+    // When the string starting with "expr-" and containing '?' and matches
+    // the table, it is taken literally.  Otherwise '?' is recognized as a
+    // wildcard.
+    for (i = (int)ARRAY_SIZE(expr_table); --i >= 0; ) {
+      if (STRCMP(arg + 5, expr_table[i]) == 0) {
+        STRCPY(d, arg);
+        break;
+      }
     }
+  } else {
+    // Recognize a few exceptions to the rule.  Some strings that contain
+    // '*' with "star".  Otherwise '*' is recognized as a wildcard.
+    for (i = (int)ARRAY_SIZE(mtable); --i >= 0; ) {
+      if (STRCMP(arg, mtable[i]) == 0) {
+        STRCPY(d, rtable[i]);
+        break;
+      }
+    }
+  }
 
   if (i < 0) {  /* no match in table */
     /* Replace "\S" with "/\\S", etc.  Otherwise every tag is matched.
diff --git a/src/nvim/testdir/test_help_tagjump.vim b/src/nvim/testdir/test_help_tagjump.vim
index 09724066b0..c873487b92 100644
--- a/src/nvim/testdir/test_help_tagjump.vim
+++ b/src/nvim/testdir/test_help_tagjump.vim
@@ -38,11 +38,34 @@ func Test_help_tagjump()
   call assert_true(getline('.') =~ '\*:?\*')
   helpclose
 
+  help q?
+  call assert_equal("help", &filetype)
+  call assert_true(getline('.') =~ '\*q?\*')
+  call assert_true(expand('<cword>') == 'q?')
+  helpclose
+
   help -?
   call assert_equal("help", &filetype)
   call assert_true(getline('.') =~ '\*-?\*')
   helpclose
 
+  help v_g?
+  call assert_equal("help", &filetype)
+  call assert_true(getline('.') =~ '\*v_g?\*')
+  helpclose
+
+  help expr-!=?
+  call assert_equal("help", &filetype)
+  call assert_true(getline('.') =~ '\*expr-!=?\*')
+  call assert_true(expand('<cword>') == 'expr-!=?')
+  helpclose
+
+  help expr-isnot?
+  call assert_equal("help", &filetype)
+  call assert_true(getline('.') =~ '\*expr-isnot?\*')
+  call assert_true(expand('<cword>') == 'expr-isnot?')
+  helpclose
+
   help FileW*Post
   call assert_equal("help", &filetype)
   call assert_true(getline('.') =~ '\*FileWritePost\*')