51348: Fix subscript completion bugs inside ~[...]

When completing inside ~[...] (_with_ the trailing `]` present), the
following bugs occured:
- Subscript completion was skipped entirely when there were one or more
  slashes ('/') in the subscript, which is incorrect, since slashes are
  allowed there.
- Instead of going through _complete, $_comps[-subscript-] was called
  immediately, causing _setup to be skipped.
- If succesful, _main_complete was exited right after, causing
  menu-style, comppostfuncs and other essential completion features to
  be skipped.

ChangeLog

@@ -1,5 +1,9 @@
 2023-05-21  Oliver Kiddle  <opk@zsh.org>
 
+	* Marlon Richert: 51682: Completion/Base/Core/_main_complete,
+	Test/Y01completion.ztst: Fix subscript completion bugs
+	inside ~[...]
+
 	* Marlon Richert: 51759: Completion/Zsh/Type/_command_names:
 	Show alias values in command completions
 

Completion/Base/Core/_main_complete

@@ -93,19 +93,15 @@ fi
 if [[ -z "$compstate[quote]" ]]; then
   if [[ -o equals ]] && compset -P 1 '='; then
     compstate[context]=equal
-  elif [[ "$PREFIX" != */* && "$PREFIX[1]" = '~' ]]; then
-    if [[ "$PREFIX" = '~['[^\]]# ]]; then
-      # Inside ~[...] should be treated as a subscript.
-      compset -p 2
-      # To be consistent, we ignore all but the contents of the square
-      # brackets.
-      compset -S '\]*'
-      compstate[context]=subscript
-      [[ -n $_comps[-subscript-] ]] && $_comps[-subscript-] && return
-    else
-      compset -p 1
-      compstate[context]=tilde
-    fi
+  elif [[ "$PREFIX" = \~\[[^]]# ]]; then
+    # Inside ~[...] should be treated as a subscript.
+    compset -p 2
+    # To be consistent, we ignore all but the contents of the square brackets.
+    compset -S '\]*'
+    compstate[context]=subscript
+  elif [[ "$PREFIX" = \~[^/]# ]]; then
+    compset -p 1
+    compstate[context]=tilde
   fi
 fi
 

Test/Y01completion.ztst

@@ -75,17 +75,27 @@
 >line: {: ~user2}{}
 >line: {: ~user1}{}
 
-  comptesteval 'zsh_directory_name() { compadd "$expl[@]" -- name1 name2 }'
+  comptesteval 'zsh_directory_name() { compadd "$expl[@]" -- name/1 name2 }'
   comptest $': ~[\t\t\t\t'
 0:dynamic directory names after ~[
 >line: {: ~[name}{}
 >line: {: ~[name}{}
 >DESCRIPTION:{dynamically named directory}
->NO:{name1}
+>NO:{name/1}
 >NO:{name2}
->line: {: ~[name1]}{}
+>line: {: ~[name/1]}{}
 >line: {: ~[name2]}{}
 
+  comptest $': ~[]\C-b\t\t\t\t'
+0:dynamic directory names inside ~[...]
+>line: {: ~[name}{]}
+>line: {: ~[name}{]}
+>DESCRIPTION:{dynamically named directory}
+>NO:{name/1}
+>NO:{name2}
+>line: {: ~[name/1}{]}
+>line: {: ~[name2}{]}
+
   comptest $'echo ;:\C-b\C-b\t'
 0:directories and files before separator
 >line: {echo }{;:}