From c79ff97c072d46931a9434692d8270198f80095c Mon Sep 17 00:00:00 2001
From: Artemis Tosini <artemis.tosini@obsidian.systems>
Date: Tue, 10 Feb 2026 12:37:49 -0500
Subject: [PATCH] Move nix::handleExceptions to libutil

This is a fairly simple function, isolated from the rest of libmain
and could be useful if new programs are made that are not part of the
main nix-cli subproject.
---
 src/libmain/include/nix/main/shared.hh |  2 --
 src/libmain/shared.cc                  | 29 -------------------------
 src/libutil/error.cc                   | 30 ++++++++++++++++++++++++++
 src/libutil/include/nix/util/error.hh  | 10 +++++++++
 4 files changed, 40 insertions(+), 31 deletions(-)

diff --git a/src/libmain/include/nix/main/shared.hh b/src/libmain/include/nix/main/shared.hh
index 43069ba82bd..9554a51d587 100644
--- a/src/libmain/include/nix/main/shared.hh
+++ b/src/libmain/include/nix/main/shared.hh
@@ -13,8 +13,6 @@
 
 namespace nix {
 
-int handleExceptions(const std::string & programName, std::function<void()> fun);
-
 /**
  * Don't forget to call initPlugins() after settings are initialized!
  * @param loadConfig Whether to load configuration from `nix.conf`, `NIX_CONFIG`, etc. May be disabled for unit tests.
diff --git a/src/libmain/shared.cc b/src/libmain/shared.cc
index e7a31210509..64498d8f46a 100644
--- a/src/libmain/shared.cc
+++ b/src/libmain/shared.cc
@@ -312,35 +312,6 @@ void printVersion(const std::string & programName)
     throw Exit();
 }
 
-int handleExceptions(const std::string & programName, std::function<void()> fun)
-{
-    ReceiveInterrupts receiveInterrupts; // FIXME: need better place for this
-
-    ErrorInfo::programName = baseNameOf(programName);
-
-    std::string error = ANSI_RED "error:" ANSI_NORMAL " ";
-    try {
-        fun();
-    } catch (Exit & e) {
-        return e.status;
-    } catch (UsageError & e) {
-        logError(e.info());
-        printError("Try '%1% --help' for more information.", programName);
-        return 1;
-    } catch (BaseError & e) {
-        logError(e.info());
-        return e.info().status;
-    } catch (std::bad_alloc & e) {
-        printError(error + "out of memory");
-        return 1;
-    } catch (std::exception & e) {
-        printError(error + e.what());
-        return 1;
-    }
-
-    return 0;
-}
-
 RunPager::RunPager()
 {
     if (!isatty(STDOUT_FILENO))
diff --git a/src/libutil/error.cc b/src/libutil/error.cc
index 35e42823ce6..c42cbd5a13e 100644
--- a/src/libutil/error.cc
+++ b/src/libutil/error.cc
@@ -2,6 +2,7 @@
 
 #include "nix/util/error.hh"
 #include "nix/util/environment-variables.hh"
+#include "nix/util/exit.hh"
 #include "nix/util/signals.hh"
 #include "nix/util/terminal.hh"
 #include "nix/util/position.hh"
@@ -455,4 +456,33 @@ void unreachable(std::source_location loc)
     panic(std::string_view(buf, std::min(static_cast<int>(sizeof(buf)), n)));
 }
 
+int handleExceptions(const std::string & programName, std::function<void()> fun)
+{
+    ReceiveInterrupts receiveInterrupts; // FIXME: need better place for this
+
+    ErrorInfo::programName = baseNameOf(programName);
+
+    std::string error = ANSI_RED "error:" ANSI_NORMAL " ";
+    try {
+        fun();
+    } catch (Exit & e) {
+        return e.status;
+    } catch (UsageError & e) {
+        logError(e.info());
+        printError("Try '%1% --help' for more information.", programName);
+        return 1;
+    } catch (BaseError & e) {
+        logError(e.info());
+        return e.info().status;
+    } catch (std::bad_alloc & e) {
+        printError(error + "out of memory");
+        return 1;
+    } catch (std::exception & e) {
+        printError(error + e.what());
+        return 1;
+    }
+
+    return 0;
+}
+
 } // namespace nix
diff --git a/src/libutil/include/nix/util/error.hh b/src/libutil/include/nix/util/error.hh
index 74bb3e4f46a..284cded8ea9 100644
--- a/src/libutil/include/nix/util/error.hh
+++ b/src/libutil/include/nix/util/error.hh
@@ -333,6 +333,16 @@ void throwExceptionSelfCheck();
 [[noreturn]]
 void panic(std::string_view msg);
 
+/**
+ * Run a function, printing an error and returning on exception.
+ * Useful for wrapping a `main` function that may throw
+ *
+ * @param programName Name of program, usually argv[0]
+ * @param fun Function to run inside the try block
+ * @return exit code: 0 if success, 1 if exception does not specify.
+ */
+int handleExceptions(const std::string & programName, std::function<void()> fun);
+
 /**
  * Print a basic error message with source position and std::terminate().
  *