From 6c8097b1b81e526f13f769b3967a8b3fb2242f92 Mon Sep 17 00:00:00 2001
From: Alan Frindell <afrind@meta.com>
Date: Thu, 12 Mar 2026 13:38:41 -0700
Subject: [PATCH] Fix CMake BUILD_SHARED_LIBS=ON support (#601)

Summary:
Pull Request resolved: https://github.com/facebook/proxygen/pull/601

The granular CMake refactoring in D91009064 broke shared library builds.

1. `proxygen_add_library()` creates INTERFACE targets for shared builds, but
   `lib/CMakeLists.txt` called `target_include_directories(... PUBLIC ...)` on
   them. CMake only allows INTERFACE properties on INTERFACE targets. These
   calls were redundant since `proxygen_add_library()` already sets the same
   include directories.

2. In `proxygen_resolve_deferred_dependencies()`, `_obj` targets could fall
   through to linking against plain INTERFACE wrapper targets, which link to
   the monolithic `proxygen` shared library. Since `proxygen` is built from
   those same `_obj` targets, this creates a dependency cycle. Skip deps
   without an `_obj` version for `_obj` targets in shared builds.

Reviewed By: jbeshay

Differential Revision: D96253183

fbshipit-source-id: 1b0a1728c014b8475834e31ff09bbed7bd912948
---
 cmake/ProxygenFunctions.cmake |  2 ++
 proxygen/lib/CMakeLists.txt   | 12 ------------
 2 files changed, 2 insertions(+), 12 deletions(-)

diff --git a/cmake/ProxygenFunctions.cmake b/cmake/ProxygenFunctions.cmake
index 7db4b04d3..a5027ce25 100644
--- a/cmake/ProxygenFunctions.cmake
+++ b/cmake/ProxygenFunctions.cmake
@@ -434,6 +434,8 @@ function(proxygen_resolve_deferred_dependencies)
       # link to _obj for include path propagation
       if(BUILD_SHARED_LIBS AND _target MATCHES "_obj$" AND TARGET ${_dep}_obj)
         list(APPEND _valid_deps ${_dep}_obj)
+      elseif(BUILD_SHARED_LIBS AND _target MATCHES "_obj$")
+        # No _obj version exists; skip to avoid cycle through monolithic library
       elseif(TARGET ${_dep})
         list(APPEND _valid_deps ${_dep})
       endif()
diff --git a/proxygen/lib/CMakeLists.txt b/proxygen/lib/CMakeLists.txt
index 37905e515..a1cc4bbfc 100644
--- a/proxygen/lib/CMakeLists.txt
+++ b/proxygen/lib/CMakeLists.txt
@@ -114,12 +114,6 @@ proxygen_add_library(proxygen_http_http_common_headers
     proxygen-generated
     Folly::folly_range
 )
-target_include_directories(proxygen_http_http_common_headers PUBLIC
-    $<BUILD_INTERFACE:${PROXYGEN_FBCODE_ROOT}>
-    $<BUILD_INTERFACE:${PROXYGEN_GENERATED_ROOT}>
-    $<INSTALL_INTERFACE:include/>
-)
-
 proxygen_add_library(proxygen_utils_trace_event_types
   SRCS
     ${PROXYGEN_GENERATED_ROOT}/proxygen/lib/utils/TraceEventType.cpp
@@ -128,12 +122,6 @@ proxygen_add_library(proxygen_utils_trace_event_types
     proxygen-generated
     Folly::folly_conv
 )
-target_include_directories(proxygen_utils_trace_event_types PUBLIC
-    $<BUILD_INTERFACE:${PROXYGEN_FBCODE_ROOT}>
-    $<BUILD_INTERFACE:${PROXYGEN_GENERATED_ROOT}>
-    $<INSTALL_INTERFACE:include/>
-)
-
 # Granular library for http_parser
 proxygen_add_library(proxygen_external_http_parser
   SRCS