2 files changed, 36 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/development/compilers/swift/sourcekit-lsp/default.nix b/nixpkgs/pkgs/development/compilers/swift/sourcekit-lsp/default.nix
index 5cf928dc424b..caba3e3441f3 100644
--- a/nixpkgs/pkgs/development/compilers/swift/sourcekit-lsp/default.nix
+++ b/nixpkgs/pkgs/development/compilers/swift/sourcekit-lsp/default.nix
@@ -40,6 +40,9 @@ stdenv.mkDerivation {
     swiftpmMakeMutable indexstore-db
     patch -p1 -d .build/checkouts/indexstore-db -i ${./patches/indexstore-db-macos-target.patch}
 
+    swiftpmMakeMutable swift-tools-support-core
+    patch -p1 -d .build/checkouts/swift-tools-support-core -i ${./patches/force-unwrap-file-handles.patch}
+
     # This toggles a section specific to Xcode XCTest, which doesn't work on
     # Darwin, where we also use swift-corelibs-xctest.
     substituteInPlace Sources/LSPTestSupport/PerfTestCase.swift \
diff --git a/nixpkgs/pkgs/development/compilers/swift/sourcekit-lsp/patches/force-unwrap-file-handles.patch b/nixpkgs/pkgs/development/compilers/swift/sourcekit-lsp/patches/force-unwrap-file-handles.patch
new file mode 100644
index 000000000000..a2f2d38c37c8
--- /dev/null
+++ b/nixpkgs/pkgs/development/compilers/swift/sourcekit-lsp/patches/force-unwrap-file-handles.patch
@@ -0,0 +1,33 @@
+From 8d9ab4b6ed24a97e8af0cc338a52aacdcf438b8c Mon Sep 17 00:00:00 2001
+From: Pavel Sobolev <paveloom@riseup.net>
+Date: Tue, 21 Nov 2023 20:53:33 +0300
+Subject: [PATCH] Force-unwrap file handles.
+
+---
+ Sources/TSCBasic/FileSystem.swift | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/Sources/TSCBasic/FileSystem.swift b/Sources/TSCBasic/FileSystem.swift
+index 3a63bdf..a1f3d9d 100644
+--- a/Sources/TSCBasic/FileSystem.swift
++++ b/Sources/TSCBasic/FileSystem.swift
+@@ -425,7 +425,7 @@ private class LocalFileSystem: FileSystem {
+         if fp == nil {
+             throw FileSystemError(errno: errno, path)
+         }
+-        defer { fclose(fp) }
++        defer { fclose(fp!) }
+
+         // Read the data one block at a time.
+         let data = BufferedOutputByteStream()
+@@ -455,7 +455,7 @@ private class LocalFileSystem: FileSystem {
+         if fp == nil {
+             throw FileSystemError(errno: errno, path)
+         }
+-        defer { fclose(fp) }
++        defer { fclose(fp!) }
+
+         // Write the data in one chunk.
+         var contents = bytes.contents
+--
+2.42.0