From 7b07b229571d80c228f7719c4ffdaf48e397f1a0 Mon Sep 17 00:00:00 2001
From: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
Date: Sun, 27 Jul 2025 15:35:58 +0100
Subject: [PATCH] cmake: Avoid contaminating parent project's cache with
 BUILD_SHARED_LIBS

The CMake cache is global in scope. Therefore, setting the standard
cache variable `BUILD_SHARED_LIBS` can inadvertently affect the behavior
of a parent project.

This change:
1. Sets the `BUILD_SHARED_LIBS` cache variable only when libsecp256k1 is
   the top-level project.
2. Removes the `SECP256K1_DISABLE_SHARED` cache variable. This enables
   parent projects that include libsecp256k1 as a subproject to rely
   solely on standard CMake variables for configuring the library type.
---
 CMakeLists.txt | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 25919fd5e6..11dc3f6e53 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -34,10 +34,8 @@ set(CMAKE_C_EXTENSIONS OFF)
 #=============================
 # Configurable options
 #=============================
-option(BUILD_SHARED_LIBS "Build shared libraries." ON)
-option(SECP256K1_DISABLE_SHARED "Disable shared library. Overrides BUILD_SHARED_LIBS." OFF)
-if(SECP256K1_DISABLE_SHARED)
-  set(BUILD_SHARED_LIBS OFF)
+if(libsecp256k1_IS_TOP_LEVEL)
+  option(BUILD_SHARED_LIBS "Build shared libraries." ON)
 endif()
 
 option(SECP256K1_INSTALL "Enable installation." ${PROJECT_IS_TOP_LEVEL})