From cb79548c49d7144345a8c14c95475dd19dca5e8f Mon Sep 17 00:00:00 2001
From: ridiculousfish <rf@fishshell.com>
Date: Mon, 25 Oct 2021 12:22:51 -0700
Subject: [PATCH] Revert "break/continue: Stop checking if it's in a loop
 again"

This reverts commit 61cd05efb0d9da46b49316be6343eb323ab5f817.

It is true that we detect break and continue errors statically, but they can
still be invoked dynamically, example:

    set sneaky break
    $sneaky # dynamically breaks from the loop

or just `eval break`.

A followup commit will add tests for this.
---
 src/builtin.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/builtin.cpp b/src/builtin.cpp
index fcd65957d..78030a4d8 100644
--- a/src/builtin.cpp
+++ b/src/builtin.cpp
@@ -270,6 +270,21 @@ static maybe_t<int> builtin_break_continue(parser_t &parser, io_streams_t &strea
         return STATUS_INVALID_ARGS;
     }
 
+    // Paranoia: ensure we have a real loop.
+    bool has_loop = false;
+    for (const auto &b : parser.blocks()) {
+        if (b.type() == block_type_t::while_block || b.type() == block_type_t::for_block) {
+            has_loop = true;
+            break;
+        }
+        if (b.is_function_call()) break;
+    }
+    if (!has_loop) {
+        wcstring error_message = format_string(_(L"%ls: Not inside of loop\n"), argv[0]);
+        builtin_print_help(parser, streams, argv[0], &error_message);
+        return STATUS_CMD_ERROR;
+    }
+
     // Mark the status in the libdata.
     parser.libdata().loop_status = is_break ? loop_status_t::breaks : loop_status_t::continues;
     return STATUS_CMD_OK;