From e61bcb45f7490706846b295d30080db3ece1d165 Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Mon, 18 Jul 2022 11:57:21 +0800
Subject: [PATCH] linkage_checker: report linkage with system frameworks
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Currently, `brew linkage` reports linkage with system frameworks only if
they can be found on the file system. This results in this linkage not
being reported on Big Sur and newer, where system libraries are stored
in the dyld cache instead.

Let's fix that by avoiding silently ignoring system frameworks by moving
them out of `#harmless_broken_link?`. We retain the behaviour desired
from 7228e60da51392b20d55e0c087b2082b86fb3bbf by deferring checking if a
broken library is actually a system framework to just before we add it
to `@broken_dylibs`.

To see how this changes the behaviour of `brew linkage`, here's an
example with this change:

    ❯ brew linkage neovim
    System libraries:
      /System/Library/Frameworks/CoreServices.framework/Versions/A/CoreServices
      /usr/lib/libSystem.B.dylib
      /usr/lib/libiconv.2.dylib
      /usr/lib/libutil.dylib
    Homebrew libraries:
      /usr/local/opt/gettext/lib/libintl.8.dylib (gettext)
      /usr/local/opt/libtermkey/lib/libtermkey.1.dylib (libtermkey)
      /usr/local/opt/libuv/lib/libuv.1.dylib (libuv)
      /usr/local/opt/luajit/lib/libluajit-5.1.2.dylib (luajit)
      /usr/local/opt/luv/lib/libluv.1.dylib (luv)
      /usr/local/opt/msgpack/lib/libmsgpackc.2.dylib (msgpack)
      /usr/local/opt/tree-sitter/lib/libtree-sitter.0.dylib (tree-sitter)
      /usr/local/opt/unibilium/lib/libunibilium.4.dylib (unibilium)

and without this change:

    ❯ brew linkage neovim
    System libraries:
      /usr/lib/libSystem.B.dylib
      /usr/lib/libiconv.2.dylib
      /usr/lib/libutil.dylib
    Homebrew libraries:
      /usr/local/opt/gettext/lib/libintl.8.dylib (gettext)
      /usr/local/opt/libtermkey/lib/libtermkey.1.dylib (libtermkey)
      /usr/local/opt/libuv/lib/libuv.1.dylib (libuv)
      /usr/local/opt/luajit/lib/libluajit-5.1.2.dylib (luajit)
      /usr/local/opt/luv/lib/libluv.1.dylib (luv)
      /usr/local/opt/msgpack/lib/libmsgpackc.2.dylib (msgpack)
      /usr/local/opt/tree-sitter/lib/libtree-sitter.0.dylib (tree-sitter)
      /usr/local/opt/unibilium/lib/libunibilium.4.dylib (unibilium)
---
 Library/Homebrew/linkage_checker.rb | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Library/Homebrew/linkage_checker.rb b/Library/Homebrew/linkage_checker.rb
index b8732b2d34..7887ffe7de 100644
--- a/Library/Homebrew/linkage_checker.rb
+++ b/Library/Homebrew/linkage_checker.rb
@@ -198,7 +198,7 @@ class LinkageChecker
             # In macOS Big Sur and later, system libraries do not exist on-disk and instead exist in a cache.
             # If dlopen finds the dylib, then the linkage is not broken.
             @system_dylibs << dylib
-          else
+          elsif !system_framework?(dylib)
             @broken_dylibs << dylib
           end
         else
@@ -306,11 +306,13 @@ class LinkageChecker
   def harmless_broken_link?(dylib)
     # libgcc_s_* is referenced by programs that use the Java Service Wrapper,
     # and is harmless on x86(_64) machines
-    return true if [
+    [
       "/usr/lib/libgcc_s_ppc64.1.dylib",
       "/opt/local/lib/libgcc/libgcc_s.1.dylib",
     ].include?(dylib)
+  end
 
+  def system_framework?(dylib)
     dylib.start_with?("/System/Library/Frameworks/")
   end