From 94605b97e74bfaf627676bfb627ae1f1f11829cd Mon Sep 17 00:00:00 2001
From: "Felix S. Klock II" <pnkfelix@pnkfx.org>
Date: Wed, 3 Jun 2020 11:46:54 -0400
Subject: [PATCH] run-make regression test for issue #70924.

---
 .../incr-add-rust-src-component/Makefile      | 39 +++++++++++++++++++
 .../incr-add-rust-src-component/main.rs       |  3 ++
 2 files changed, 42 insertions(+)
 create mode 100644 src/test/run-make-fulldeps/incr-add-rust-src-component/Makefile
 create mode 100644 src/test/run-make-fulldeps/incr-add-rust-src-component/main.rs

diff --git a/src/test/run-make-fulldeps/incr-add-rust-src-component/Makefile b/src/test/run-make-fulldeps/incr-add-rust-src-component/Makefile
new file mode 100644
index 0000000000000..164cc8a5d5fe0
--- /dev/null
+++ b/src/test/run-make-fulldeps/incr-add-rust-src-component/Makefile
@@ -0,0 +1,39 @@
+-include ../tools.mk
+
+# rust-lang/rust#70924: Test that if we add rust-src component in between two
+# incremetnal compiles, the compiler does not ICE on the second.
+
+SYSROOT:=$(shell $(RUSTC) --print sysroot)
+FAKEROOT=$(TMPDIR)/fakeroot
+INCR=$(TMPDIR)/incr
+
+# Make a local copy of the sysroot; then remove the rust-src part of it, if
+# present, for the *first* build. Then put in a facsimile of the rust-src
+# component for the second build, in order to expose the ICE from issue #70924.
+#
+# Note that it is much easier to just do `cp -a $(SYSROOT)/* $(FAKEROOT)` as a
+# first step, but I am concerned that would be too expensive in a unit test
+# compared to making symbolic links.
+#
+# Anyway, the pattern you'll see here is: For every prefix in
+# root/lib/rustlib/src, link all of prefix parent content, then remove the
+# prefix, then loop on the next prefix. This way, we basically create a copy of
+# the context around root/lib/rustlib/src, and can freely add/remove the src
+# component itself.
+all:
+	mkdir $(FAKEROOT)
+	ln -s $(SYSROOT)/* $(FAKEROOT)
+	rm -f $(FAKEROOT)/lib
+	mkdir $(FAKEROOT)/lib
+	ln -s $(SYSROOT)/lib/* $(FAKEROOT)/lib
+	rm -f $(FAKEROOT)/lib/rustlib
+	mkdir $(FAKEROOT)/lib/rustlib
+	ln -s $(SYSROOT)/lib/rustlib/* $(FAKEROOT)/lib/rustlib
+	rm -f $(FAKEROOT)/lib/rustlib/src
+	mkdir $(FAKEROOT)/lib/rustlib/src
+	ln -s $(SYSROOT)/lib/rustlib/src/* $(FAKEROOT)/lib/rustlib/src
+	rm -f $(FAKEROOT)/lib/rustlib/src/rust
+	$(RUSTC) --sysroot $(FAKEROOT) -C incremental=$(INCR) main.rs
+	mkdir -p $(FAKEROOT)/lib/rustlib/src/rust/src/libstd
+	touch $(FAKEROOT)/lib/rustlib/src/rust/src/libstd/lib.rs
+	$(RUSTC) --sysroot $(FAKEROOT) -C incremental=$(INCR) main.rs
diff --git a/src/test/run-make-fulldeps/incr-add-rust-src-component/main.rs b/src/test/run-make-fulldeps/incr-add-rust-src-component/main.rs
new file mode 100644
index 0000000000000..f6320bcb04aa8
--- /dev/null
+++ b/src/test/run-make-fulldeps/incr-add-rust-src-component/main.rs
@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello World");
+}