Merge bitcoin/bitcoin#28981: Replace Boost.Process with cpp-subprocess

d5a715536e497c160a2520f81334aab6c7490213 build: remove boost::process dependency for building external signer support (Sebastian Falbesoner)
70434b1c443d9251a880d0193af771f574c40617 external_signer: replace boost::process with cpp-subprocess (Sebastian Falbesoner)
cc8b9875b104c31f0a5b5e4195a8278ec55f35f7 Add `cpp-subprocess` header-only library (Hennadii Stepanov)

Pull request description:

  Closes https://github.com/bitcoin/bitcoin/issues/24907.

  This PR is based on **theStack**'s [work](https://github.com/bitcoin/bitcoin/issues/24907#issuecomment-1466087049).

  The `subprocess.hpp` header has been sourced from the [upstream repo](https://github.com/arun11299/cpp-subprocess) with the only modification being the removal of convenience functions, which are not utilized in our codebase.

  Windows-related changes will be addressed in subsequent follow-ups.

ACKs for top commit:
  achow101:
    reACK d5a715536e497c160a2520f81334aab6c7490213
  Sjors:
    re-tACK d5a715536e497c160a2520f81334aab6c7490213
  theStack:
    Light re-ACK d5a715536e497c160a2520f81334aab6c7490213
  fanquake:
    ACK d5a715536e497c160a2520f81334aab6c7490213 - with the expectation that this code is going to be maintained as our own. Next PRs should:

Tree-SHA512: d7fb6fecc3f5792496204190afb7d85b3e207b858fb1a75efe483c05260843b81b27d14b299323bb667c990e87a07197059afea3796cf218ed8b614086bd3611

1 files changed, 5 insertions, 9 deletions

diff --git a/src/test/system_tests.cpp b/src/test/system_tests.cpp
index 90fce9adf9..8aab2b565c 100644
--- a/src/test/system_tests.cpp
+++ b/src/test/system_tests.cpp
@@ -11,7 +11,7 @@
 #include <univalue.h>
 
 #ifdef ENABLE_EXTERNAL_SIGNER
-#include <boost/process.hpp>
+#include <util/subprocess.hpp>
 #endif // ENABLE_EXTERNAL_SIGNER
 
 #include <boost/test/unit_test.hpp>
@@ -34,20 +34,16 @@ BOOST_AUTO_TEST_CASE(run_command)
         BOOST_CHECK(result.isNull());
     }
     {
-        const UniValue result = RunCommandParseJSON("echo \"{\"success\": true}\"");
+        const UniValue result = RunCommandParseJSON("echo {\"success\": true}");
         BOOST_CHECK(result.isObject());
         const UniValue& success = result.find_value("success");
         BOOST_CHECK(!success.isNull());
         BOOST_CHECK_EQUAL(success.get_bool(), true);
     }
     {
-        // An invalid command is handled by Boost
-        const int expected_error{2};
-        BOOST_CHECK_EXCEPTION(RunCommandParseJSON("invalid_command"), boost::process::process_error, [&](const boost::process::process_error& e) {
-            BOOST_CHECK(std::string(e.what()).find("RunCommandParseJSON error:") == std::string::npos);
-            BOOST_CHECK_EQUAL(e.code().value(), expected_error);
-            return true;
-        });
+        // An invalid command is handled by cpp-subprocess
+        const std::string expected{"execve failed: "};
+        BOOST_CHECK_EXCEPTION(RunCommandParseJSON("invalid_command"), subprocess::CalledProcessError, HasReason(expected));
     }
     {
         // Return non-zero exit code, no output to stderr