From f14e3ee38ff234ca00cb73b61bf306316b9ab91d Mon Sep 17 00:00:00 2001
From: Martin Nordholts <martin.nordholts@codetale.se>
Date: Thu, 15 Jan 2026 06:12:57 +0100
Subject: [PATCH] compiletest: Don't assume `aux-crate` becomes a `*.so` with
 `no-prefer-dynamic`

Since it does not make sense to do so. If someone prefers no dynamic
stuff, the last thing they want to look for is an `.so` file. Also add a
regression test. Without the fix, the test fails with:

    error: test compilation failed although it shouldn't!
    --- stderr -------------------------------
    error: extern location for no_prefer_dynamic_lib does not exist: .../auxiliary/libno_prefer_dynamic_lib.so
      --> .../no-prefer-dynamic-means-no-so.rs:9:5
       |
    LL |     no_prefer_dynamic_lib::return_42();
       |     ^^^^^^^^^^^^^^^^^^^^^
---
 src/tools/compiletest/src/runtest.rs                   |  2 +-
 .../auxiliary/no_prefer_dynamic_lib.rs                 | 10 ++++++++++
 .../no-prefer-dynamic-means-no-so.rs                   | 10 ++++++++++
 3 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 tests/ui/compiletest-self-test/auxiliary/no_prefer_dynamic_lib.rs
 create mode 100644 tests/ui/compiletest-self-test/no-prefer-dynamic-means-no-so.rs

diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index ef90b81fb2a73..1804490a5f12c 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -1438,7 +1438,7 @@ impl<'test> TestCx<'test> {
         } else if aux_type.is_some() {
             panic!("aux_type {aux_type:?} not expected");
         } else if aux_props.no_prefer_dynamic {
-            (AuxType::Dylib, None)
+            (AuxType::Lib, None)
         } else if self.config.target.contains("emscripten")
             || (self.config.target.contains("musl")
                 && !aux_props.force_host
diff --git a/tests/ui/compiletest-self-test/auxiliary/no_prefer_dynamic_lib.rs b/tests/ui/compiletest-self-test/auxiliary/no_prefer_dynamic_lib.rs
new file mode 100644
index 0000000000000..6688dadbab24f
--- /dev/null
+++ b/tests/ui/compiletest-self-test/auxiliary/no_prefer_dynamic_lib.rs
@@ -0,0 +1,10 @@
+//@ no-prefer-dynamic
+
+//! Since this is `no-prefer-dynamic` we expect compiletest to _not_ look for
+//! this create as `libno_prefer_dynamic_lib.so`.
+
+#![crate_type = "rlib"]
+
+pub fn return_42() -> i32 {
+    42
+}
diff --git a/tests/ui/compiletest-self-test/no-prefer-dynamic-means-no-so.rs b/tests/ui/compiletest-self-test/no-prefer-dynamic-means-no-so.rs
new file mode 100644
index 0000000000000..b7e8fae506c39
--- /dev/null
+++ b/tests/ui/compiletest-self-test/no-prefer-dynamic-means-no-so.rs
@@ -0,0 +1,10 @@
+//! Since we and our `aux-crate` is `no-prefer-dynamic`, we expect compiletest
+//! to _not_ look for `libno_prefer_dynamic_lib.so`.
+
+//@ check-pass
+//@ no-prefer-dynamic
+//@ aux-crate: no_prefer_dynamic_lib=no_prefer_dynamic_lib.rs
+
+fn main() {
+    no_prefer_dynamic_lib::return_42();
+}