From d50fdf89229ba2f65310c0a2f7a5fbf16d954fe6 Mon Sep 17 00:00:00 2001
From: Tim Dawborn <tim.dawborn@airtasker.com>
Date: Thu, 20 Mar 2025 23:05:01 +1000
Subject: [PATCH] Fix `gcc` install check.

---
 setup-fortran.sh | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/setup-fortran.sh b/setup-fortran.sh
index 89958b2..128f0ea 100755
--- a/setup-fortran.sh
+++ b/setup-fortran.sh
@@ -45,14 +45,23 @@ install_gcc_brew()
 
 install_gcc_apt()
 {
-  # check if gcc preinstalled via apt
+  # Check whether the system gcc version is the version we are after.
   cur=$(apt show gcc | grep "Version" | cut -d':' -f3 | cut -d'-' -f1)
   maj=$(echo $cur | cut -d'.' -f1)
+  needs_install=1
   if [ "$maj" == "$version" ]; then
-    echo "GCC $version already installed"
+    # Check whether that version is installed.
+    if apt list --installed gcc-${version} | grep -q "gcc-${version}/"; then
+      echo "GCC $version already installed"
+      needs_install=0
+    fi
   else
+    # Install the PPA for installing other versions of gcc.
     sudo add-apt-repository --yes ppa:ubuntu-toolchain-r/test
     sudo apt-get update
+  fi
+
+  if [ "${needs_install}" == "1" ]; then
     sudo apt-get install -y gcc-${version} gfortran-${version} g++-${version}
   fi