From 4c8f6d2d551a02a105e73dd7b40abc964ae0cace Mon Sep 17 00:00:00 2001
From: ramen-bully <248799758+ramen-bully@users.noreply.github.com>
Date: Wed, 13 May 2026 17:56:50 -0500
Subject: [PATCH] ldc-build-runtime: require absolute --buildDir for --reset
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When --reset / --resetOnly is passed and --buildDir is a relative
path (including the default `ldc-build-runtime.tmp`), the deletion
loop resolves the path against the current working directory at the
moment the tool runs. If that CWD happens to be a project root —
for example `ldc-build-runtime --buildDir=. --reset` invoked from
the project — the loop iterates the project's top-level entries and
removes every file plus every subdirectory not literally named
`ldc-src`. This has destroyed working repositories.

Refuse to proceed when --reset is requested with a relative
--buildDir, and resolve the path to absolute before any deletion
runs. Builds without --reset continue to accept relative paths
unchanged (no deletion happens, so no destruction risk).
---
 runtime/ldc-build-runtime.d.in | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/runtime/ldc-build-runtime.d.in b/runtime/ldc-build-runtime.d.in
index 226c09f8df..b028064c35 100644
--- a/runtime/ldc-build-runtime.d.in
+++ b/runtime/ldc-build-runtime.d.in
@@ -77,6 +77,14 @@ void prepareBuildDir() {
     if (config.buildDir is null)
         config.buildDir = "ldc-build-runtime.tmp";
 
+    if (config.resetBuildDir && !config.buildDir.isAbsolute) {
+        writefln(".: Error: --reset / --resetOnly requires --buildDir to be an absolute path (got %s)",
+            config.buildDir);
+        exit(1);
+    }
+
+    config.buildDir = config.buildDir.absolutePath;
+
     if (config.buildDir.exists) {
         if (!config.resetBuildDir) {
             writefln(".: Warning: build directory already exists: %s", config.buildDir);
@@ -96,8 +104,6 @@ void prepareBuildDir() {
         writefln(".: Creating build directory: %s", config.buildDir);
         mkdirRecurse(config.buildDir);
     }
-
-    config.buildDir = config.buildDir.absolutePath;
 }
 
 void prepareLdcSource() {