From b9f8c4af4057c2ed0ec5d1ff16ac49e0612ad57c Mon Sep 17 00:00:00 2001
From: Sergei Zimmerman <145775305+xokdvium@users.noreply.github.com>
Date: Thu, 14 Nov 2024 02:06:59 +0300
Subject: [PATCH] fix(libmain/common-args): do not exceed maximum allowed
 verbosity

This patch gets rid of UB when verbosity exceeds the maximum logging value of `lvlVomit = 7` and
reaches invalid values (e.g. 8). This is actually triggered in functional tests.
There are too many occurrences to list, but here's one from the UBSAN log:

../src/libstore/gc.cc:610:5: runtime error: load of value 8, which is not a valid value for type 'Verbosity'
---
 src/libmain/common-args.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/libmain/common-args.cc b/src/libmain/common-args.cc
index 768b2177c..13d358623 100644
--- a/src/libmain/common-args.cc
+++ b/src/libmain/common-args.cc
@@ -17,7 +17,9 @@ MixCommonArgs::MixCommonArgs(const std::string & programName)
         .shortName = 'v',
         .description = "Increase the logging verbosity level.",
         .category = loggingCategory,
-        .handler = {[]() { verbosity = (Verbosity) (verbosity + 1); }},
+        .handler = {[]() {
+            verbosity = (Verbosity) std::min<std::underlying_type_t<Verbosity>>(verbosity + 1, lvlVomit);
+        }},
     });
 
     addFlag({