From b34a3f2772394e508a06f70db6ae48c8be0f3b13 Mon Sep 17 00:00:00 2001
From: Jake Lishman <jake.lishman@ibm.com>
Date: Sun, 24 Mar 2024 20:57:45 +0000
Subject: [PATCH] Improve mesage on failed Graphviz optional (#11896)

* Improve mesage on failed Graphviz optional

I have recently seen several users struggle to install a complete
version of Graphviz upon seeing the `MissingOptionalLibraryError`
message.  This updates the message to make it clearer that the PyPI
distribution `graphviz` *is not* the actual Graphviz software, and it
must be installed separately.

* Tweak message

(cherry picked from commit 17949dc228bca54d01ff9a16b8c93e2eb690bf69)
---
 qiskit/utils/optionals.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/qiskit/utils/optionals.py b/qiskit/utils/optionals.py
index ba0b8d8fc1f..7f399094bb6 100644
--- a/qiskit/utils/optionals.py
+++ b/qiskit/utils/optionals.py
@@ -307,8 +307,12 @@
 
 HAS_GRAPHVIZ = _LazySubprocessTester(
     ("dot", "-V"),
-    name="graphviz",
-    install="'brew install graphviz' if on Mac, or by downloding it from their website",
+    name="Graphviz",
+    msg=(
+        "To install, follow the instructions at https://graphviz.org/download/."
+        " Qiskit needs the Graphviz binaries, which the 'graphviz' package on pip does not install."
+        " You must install the actual Graphviz software"
+    ),
 )
 HAS_PDFLATEX = _LazySubprocessTester(
     ("pdflatex", "-version"),