From 79d7505db09d7c6ab508baf7b021c15d02e158a6 Mon Sep 17 00:00:00 2001
From: Jonas Devlieghere <jonas@devlieghere.com>
Date: Thu, 16 Jan 2025 16:31:20 -0800
Subject: [PATCH] [Swift REPL] Inherit the environment for the Swift REPL

The Swift REPL was had rolling the ProcessLaunchInfo instead of using
the one already setup by the target. While populating the launch info,
it used `Target::GetTargetEnvironment()` which only looks at the
corresponding setting, and ignoring the `inherit-environment` setting.
The alternative of calling `Target::GetInheritedEnvironment` is also
wrong, because that has the inverse problem: it only inherits the
environment and doesn't merge it with the target's environment
variables. The solution is to use `Target::GetProcessLaunchInfo` which
populates the launch info correctly.

Propagating the environment correctly is particularly important on
Windows where `Path` needs to be passed to the inferior to allow
`LoadLibraryW(L"swiftCore.dll")` to succeed. Without this patch, the
library is not found and the inferior exits terminating the REPL
instance.

- Fixes: llvm/llvm-project#9551
- Will fix swiftlang/swift#76702 and swiftlang/swift#70005 with a
  corresponding driver change to set `inherit-environment` when invoking
  the REPL.

rdar://137522456
---
 .../Plugins/ExpressionParser/Swift/SwiftREPL.cpp    | 13 ++++---------
 lldb/test/Shell/SwiftREPL/EnvVars.test              | 10 ++++++++++
 2 files changed, 14 insertions(+), 9 deletions(-)
 create mode 100644 lldb/test/Shell/SwiftREPL/EnvVars.test

diff --git a/lldb/source/Plugins/ExpressionParser/Swift/SwiftREPL.cpp b/lldb/source/Plugins/ExpressionParser/Swift/SwiftREPL.cpp
index 73dbfc3f4950bff..b7ca575e830c927 100644
--- a/lldb/source/Plugins/ExpressionParser/Swift/SwiftREPL.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Swift/SwiftREPL.cpp
@@ -188,15 +188,11 @@ lldb::REPLSP SwiftREPL::CreateInstanceFromDebugger(Status &err,
                                     // breakpoint above, it better
                                     // say it is internal
 
-  lldb_private::ProcessLaunchInfo launch_info;
-  llvm::StringRef target_settings_argv0 = target_sp->GetArg0();
-
-  if (target_sp->GetDisableASLR())
-    launch_info.GetFlags().Set(eLaunchFlagDisableASLR);
-
-  if (target_sp->GetDisableSTDIO())
-    launch_info.GetFlags().Set(eLaunchFlagDisableSTDIO);
+  lldb_private::ProcessLaunchInfo launch_info =
+      target_sp->GetProcessLaunchInfo();
 
+  // FIXME: Why is this necessary? Document or change once we know the answer.
+  llvm::StringRef target_settings_argv0 = target_sp->GetArg0();
   if (!target_settings_argv0.empty()) {
     launch_info.GetArguments().AppendArgument(target_settings_argv0);
     launch_info.SetExecutableFile(exe_module_sp->GetPlatformFileSpec(), false);
@@ -204,7 +200,6 @@ lldb::REPLSP SwiftREPL::CreateInstanceFromDebugger(Status &err,
     launch_info.SetExecutableFile(exe_module_sp->GetPlatformFileSpec(), true);
   }
 
-  launch_info.GetEnvironment() = target_sp->GetTargetEnvironment();
   debugger.SetAsyncExecution(false);
   err = target_sp->Launch(launch_info, nullptr);
   debugger.SetAsyncExecution(true);
diff --git a/lldb/test/Shell/SwiftREPL/EnvVars.test b/lldb/test/Shell/SwiftREPL/EnvVars.test
new file mode 100644
index 000000000000000..3c75928b0d409a3
--- /dev/null
+++ b/lldb/test/Shell/SwiftREPL/EnvVars.test
@@ -0,0 +1,10 @@
+// Test inheriting environment variables in the REPL.
+// REQUIRES: system-darwin
+// REQUIRES: swift
+
+// RUN: FOO=foo %lldb --repl -O 'settings set target.inherit-env true' < %s 2>&1 \
+// RUN: | FileCheck %s
+
+import Foundation
+ProcessInfo.processInfo.environment["FOO"]
+// CHECK: $R0: String? = "foo"