From 5360a25f972a94fb92ce2d038224a541553601cb Mon Sep 17 00:00:00 2001
From: Fredrik Bagge Carlson <baggepinnen@gmail.com>
Date: Fri, 15 Dec 2023 06:23:57 +0100
Subject: [PATCH] Fix Bode plot with zero magnitude

Closes #438
---
 lib/ControlSystemsBase/src/plotting.jl | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/ControlSystemsBase/src/plotting.jl b/lib/ControlSystemsBase/src/plotting.jl
index e4f62ea0c..667567266 100644
--- a/lib/ControlSystemsBase/src/plotting.jl
+++ b/lib/ControlSystemsBase/src/plotting.jl
@@ -292,9 +292,11 @@ end
         else
             sbal = s
         end
-        mag, phase = bode(sbal, w; unwrap=false)[1:2]
+        mag, phase = bode(sbal, w; unwrap=false)
         if _PlotScale == "dB" # Set by setPlotScale(str) globally
             mag = 20*log10.(mag)
+        elseif 0 ∈ mag
+            replace!(mag, 0 => -Inf) # To prevent plot crashing when some magnitude is exactly zero
         end
 
         xlab = plotphase ? "" : (hz ? "Frequency [Hz]" : "Frequency [rad/s]")