From 1cc8ee8465ce69fedf0270a0b76b3133891e53c8 Mon Sep 17 00:00:00 2001
From: Neil Spring <ntspring@meta.com>
Date: Fri, 23 Oct 2026 10:57:18 -0700
Subject: [PATCH] getdeps: Fix shared libfolly link in no-system-packages
 builds

Summary:
Fix the `oss-metaroce-linux-getdeps` continuous job, which fails when linking shared `libfolly.so` because source-built `libevent`, `zlib`, and `libaio` produce only static archives without position-independent code.

Enable PIC for `zlib` and `libevent` (consistent with other manifests), and switch `libaio` to produce shared libraries so folly can link against them. Add a regression test that guards against these link inputs silently reverting.

Re-enabling shared `libaio` was previously reverted (D93644345) but verified safe via a no-system-packages moxygen build. Blast radius is narrow: only `folly` and `cachelib` consume source-built libaio, and only `metaroce`/`rebalancer(-explorer)` request shared folly.

Reviewed By: bigfootjon

Differential Revision: D126978432

fbshipit-source-id: 56c67f890e2f99ecd3ae800f82adba71e475bcf9
---
 .../getdeps/test/manifest_test.py             | 31 +++++++++++++++++++
 build/fbcode_builder/manifests/libaio         |  4 +--
 build/fbcode_builder/manifests/libevent       |  1 +
 build/fbcode_builder/manifests/zlib           |  3 ++
 4 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/build/fbcode_builder/getdeps/test/manifest_test.py b/build/fbcode_builder/getdeps/test/manifest_test.py
index 9c66f3263..a2868a069 100644
--- a/build/fbcode_builder/getdeps/test/manifest_test.py
+++ b/build/fbcode_builder/getdeps/test/manifest_test.py
@@ -5,7 +5,9 @@
 
 
 import unittest
+from unittest.mock import MagicMock
 
+from ..buildopts import BuildOptions
 from ..load import load_all_manifests, patch_loader
 from ..manifest import ManifestParser
 
@@ -223,6 +225,35 @@ foo = bar
         manifests = load_all_manifests(None)
         self.assertNotEqual(0, len(manifests), msg="parsed some number of manifests")
 
+    def test_shared_folly_link_inputs(self) -> None:
+        # Shared libfolly.so links third-party static archives. Those archives
+        # must be position-independent, and libaio must install a shared
+        # library, or the no-system-packages builds fail in the folly link.
+        patch_loader(__name__)
+        # The resource loader ignores build options; a mock only satisfies
+        # the type signature.
+        manifests = load_all_manifests(MagicMock(spec=BuildOptions))
+        for name in ("zlib", "libevent", "libaio"):
+            self.assertIn(name, manifests, msg="manifest still exists")
+        for name in ("zlib", "libevent"):
+            defines = manifests[name].get_section_as_dict("cmake.defines", {})
+            self.assertEqual(
+                defines.get("CMAKE_POSITION_INDEPENDENT_CODE"),
+                "ON",
+                msg=name + " archives stay linkable into shared libfolly.so",
+            )
+        libaio = manifests["libaio"]
+        self.assertIn(
+            "ENABLE_SHARED=1",
+            libaio.get_section_as_args("make.build_args", {}),
+            msg="source-built libaio provides libaio.so with version nodes",
+        )
+        self.assertIn(
+            "ENABLE_SHARED=1",
+            libaio.get_section_as_args("make.install_args", {}),
+            msg="source-built libaio installs libaio.so with version nodes",
+        )
+
     def test_mismatch_name(self) -> None:
         with self.assertRaisesRegex(
             Exception,
diff --git a/build/fbcode_builder/manifests/libaio b/build/fbcode_builder/manifests/libaio
index 98690fbfa..acd0a48e4 100644
--- a/build/fbcode_builder/manifests/libaio
+++ b/build/fbcode_builder/manifests/libaio
@@ -17,8 +17,8 @@ builder = make
 subdir = libaio-0.3.113
 
 [make.build_args]
-ENABLE_SHARED=0
+ENABLE_SHARED=1
 
 [make.install_args]
 install
-ENABLE_SHARED=0
+ENABLE_SHARED=1
diff --git a/build/fbcode_builder/manifests/libevent b/build/fbcode_builder/manifests/libevent
index b0bc66ec1..9c77f7efe 100644
--- a/build/fbcode_builder/manifests/libevent
+++ b/build/fbcode_builder/manifests/libevent
@@ -30,6 +30,7 @@ EVENT__DISABLE_BENCHMARK = ON
 EVENT__DISABLE_SAMPLES = ON
 EVENT__DISABLE_REGRESS = ON
 EVENT__LIBRARY_TYPE = STATIC
+CMAKE_POSITION_INDEPENDENT_CODE = ON
 
 [dependencies.not(any(os=linux, os=freebsd))]
 openssl
diff --git a/build/fbcode_builder/manifests/zlib b/build/fbcode_builder/manifests/zlib
index ae77a3bad..dfb0e41a7 100644
--- a/build/fbcode_builder/manifests/zlib
+++ b/build/fbcode_builder/manifests/zlib
@@ -27,3 +27,6 @@ sha256 = 9a93b2b7dfdac77ceba5a558a580e74667dd6fede4585b91eefb60f03b72df23
 builder = cmake
 subdir = zlib-1.3.1
 patchfile = zlib_dont_build_more_than_needed.patch
+
+[cmake.defines]
+CMAKE_POSITION_INDEPENDENT_CODE = ON