From 7c1d171a7acb16279277bfc18ee55b2e45f110af Mon Sep 17 00:00:00 2001
From: Kate <kit-ty-kate@outlook.com>
Date: Tue, 22 Oct 2024 16:45:51 +0100
Subject: [PATCH] Lookup at gpatch before patch on macOS now that both homebrew
 and macports expose gpatch as gpatch

Homebrew changed behaviour in Homebrew/homebrew-core#174687
---
 .github/workflows/ci.ml        | 1 +
 .github/workflows/main.yml     | 2 ++
 master_changes.md              | 1 +
 src/client/opamInitDefaults.ml | 2 +-
 src/core/opamSystem.ml         | 2 +-
 5 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.ml b/.github/workflows/ci.ml
index 9ff06d19121..ffd1e3bd225 100644
--- a/.github/workflows/ci.ml
+++ b/.github/workflows/ci.ml
@@ -333,6 +333,7 @@ let main_build_job ~analyse_job ~cygwin_job ?section runner start_version ~oc ~w
   let host = host_of_platform platform in
   job ~oc ~workflow ~runs_on:(Runner [runner]) ?shell ?section ~needs ~matrix ("Build-" ^ name_of_platform platform)
     ++ only_on Linux (run "Install bubblewrap" ["sudo apt install bubblewrap"])
+    ++ only_on MacOS (run "Install GNU patch" ["brew install gpatch"])
     ++ only_on Windows (git_lf_checkouts ~cond:(Predicate(true, EndsWith("matrix.host", "-pc-cygwin"))) ~shell:"cmd" ~title:"Configure LF checkout for Cygwin" ())
     ++ checkout ()
     ++ only_on Windows (cache ~cond:(Predicate(true, Compare("matrix.build", "x86_64-pc-cygwin"))) Cygwin)
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 5ee3dc78f71..377b09bdf32 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -245,6 +245,8 @@ jobs:
         ocamlv: [ 4.14.2, 5.2.0 ]
       fail-fast: true
     steps:
+    - name: Install GNU patch
+      run: brew install gpatch
     - name: Checkout tree
       uses: actions/checkout@v4
     - name: src_ext/archives and opam-repository Cache
diff --git a/master_changes.md b/master_changes.md
index 1761ed7f9b7..ca9de2e8f99 100644
--- a/master_changes.md
+++ b/master_changes.md
@@ -66,6 +66,7 @@ users)
 ## Opamfile
 
 ## External dependencies
+  * Lookup at `gpatch` before `patch` on macOS now that both homebrew and macports expose `gpatch` as `gpatch` since Homebrew/homebrew-core#174687 [#6255 @kit-ty-kate]
 
 ## Format upgrade
 
diff --git a/src/client/opamInitDefaults.ml b/src/client/opamInitDefaults.ml
index 6b5a7017fbf..a6a18f20ade 100644
--- a/src/client/opamInitDefaults.ml
+++ b/src/client/opamInitDefaults.ml
@@ -57,7 +57,7 @@ let sandbox_filter = FOr (linux_filter, macos_filter)
 
 let gpatch_filter =
   FOr (FOr (openbsd_filter, netbsd_filter),
-       FOr (freebsd_filter, dragonflybsd_filter))
+       FOr (freebsd_filter, FOr (dragonflybsd_filter, macos_filter)))
 let patch_filter = FNot gpatch_filter
 
 let gtar_filter = openbsd_filter
diff --git a/src/core/opamSystem.ml b/src/core/opamSystem.ml
index 75dbb588743..def6ee5159e 100644
--- a/src/core/opamSystem.ml
+++ b/src/core/opamSystem.ml
@@ -1570,12 +1570,12 @@ let gpatch = lazy begin
   in
   let default_cmd, other_cmds =
     match OpamStd.Sys.os () with
+    | Darwin
     | DragonFly
     | FreeBSD
     | NetBSD
     | OpenBSD -> ("gpatch", ["patch"])
     | Cygwin
-    | Darwin
     | Linux
     | Unix
     | Win32