debugger: prevent running from Tarantool REPL

At the moment we are not yet compatible with readline
support inside of Tarantool console. Diagnose that situation
at the moment debugger started and bail out.

NO_TEST=interactive
NO_DOC=Markdown updated

changelogs/unreleased/gh-7593-console-debugger.md

@@ -4,3 +4,17 @@
   builtin Lua modules;
 * New Lua API created `tarantool.debug.getsources()` which allows
   to see sources of builtin modules in any external debugger;
+
+NB! Debugger REPL is not yet compatible with Tarantool console, i.e. this
+code will hang in terminal
+
+```lua
+tarantool> dbg = require 'luadebug'
+---
+...
+
+tarantool> dbg()
+---
+```
+One should call debugger activation only in their instrumented code, not
+from interactive console.

third_party/lua/README-luadebug.md

@@ -114,6 +114,16 @@ Want to disable ANSI color support or disable GNU readline? Set the `NO_COLOR`.
 Known Issues:
 -
 
+- Debugger REPL is not yet compatible with Tarantool console, i.e. this
+  code will hang in terminal
+
+```lua
+tarantool> dbg = require 'luadebug'
+tarantool> dbg()
+```
+  One should call debugger activation only in their instrumented code, not
+  from interactive console.
+
 - Lua 5.1 lacks the API to access varargs. The workaround is to do something like `local args = {...}` and then use `unpack(args)` when you want to access them. In Lua 5.2+ and LuaJIT, you can simply use `...` in your expressions with the print command.
 - You can't add breakpoints to a running program or remove them. Currently the only way to set them is by explicitly calling the `dbg()` function explicitly in your code. (This is sort of by design and sort of because it's difficult/slow otherwise.)
 - Different interpreters (and versions) print out slightly different stack trace information.

third_party/lua/luadebug.lua

@@ -730,6 +730,15 @@ dbg = setmetatable({
             return
         end
 
+        --[[
+            Prevent debugger from running from inside of Tarantool console.
+            Check pointer, which Tarantool console stored to the console object
+            in the fiber.self().storage.console while inside of
+            REPL loop.
+        --]]
+        assert(require('fiber').self().storage.console == nil, DEBUGGER ..
+            ' is not yet compatible with interactive Tarantool console')
+
         top_offset = top_offset or 0
         stack_inspect_offset = top_offset
         stack_top = top_offset