From d1564cb5a0b641222c15c7360b24e265f3b92c40 Mon Sep 17 00:00:00 2001
From: Jim Newsome <jnewsome@torproject.org>
Date: Wed, 25 Jan 2023 14:58:28 -0600
Subject: [PATCH] Specify igraph < 0.10.0

igraph 0.10.0 has some API changes that we don't handle. We may be able
to support it through some #ifdef macros, as we already do for 0.9.x,
though the devs suggest this might be painful.

For now, having cmake bail out and explain that the igraph version is
incompatible is better than having a bunch of compiler errors.

See https://github.com/shadow/tgen/issues/44
---
 CMakeLists.txt | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 773b623..1d535f1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,7 +16,12 @@ include(FindPkgConfig)
 find_package(RT REQUIRED)
 find_package(M REQUIRED)
 
-pkg_check_modules(IGRAPH REQUIRED igraph)
+# We don't yet support igraph 0.10.0+, which has some API changes.
+# See https://github.com/shadow/tgen/issues/44
+#
+# Older versions of cmake don't support the `<` operator here; only `<=`.
+pkg_check_modules(IGRAPH REQUIRED igraph<=0.9.9999)
+
 pkg_check_modules(GLIB REQUIRED glib-2.0)
 
 ## Parse out igraph version. Needed to work around breaking API changes in igraph.