From b8777d789300ee9c2d860c7156f4cd9b8da43f76 Mon Sep 17 00:00:00 2001
From: Krystine Sherwin <93062060+KrystalDelusion@users.noreply.github.com>
Date: Tue, 18 Feb 2025 11:25:04 +1300
Subject: [PATCH] Makefile: Warn if submodule status '+'-prefixed

A '+'-prefix means that the submodule is initialized and checked out, but a different commit is checked out.
If this is accidental then the user should run `git submodule update` to fix it.
If it is intentional (because e.g. the user is explicitly wanting to test Yosys with a different version of abc), then creating a new commit in Yosys to update the expected commit is also a valid solution.
---
 Makefile | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Makefile b/Makefile
index fd4d27915..b1853f77a 100644
--- a/Makefile
+++ b/Makefile
@@ -775,6 +775,11 @@ check-git-abc:
 	elif [ -f "$(YOSYS_SRC)/abc/.gitcommit" ] && ! grep -q '\$$Format:%[hH]\$$' "$(YOSYS_SRC)/abc/.gitcommit"; then \
 		echo "'abc' comes from a tarball. Continuing."; \
 		exit 0; \
+	elif git -C "$(YOSYS_SRC)" submodule status abc 2>/dev/null | grep -q '^+'; then \
+		echo "'abc' submodule does not match expected commit."; \
+		echo "Run 'git submodule update' to check out the correct version."; \
+		echo "Note: If testing a different version of abc, call `git commit abc` in the Yosys source directory to update the expected commit."; \
+		exit 1; \
 	elif [ -f "$(YOSYS_SRC)/abc/.gitcommit" ] && grep -q '\$$Format:%[hH]\$$' "$(YOSYS_SRC)/abc/.gitcommit"; then \
 		echo "Error: 'abc' is not configured as a git submodule."; \
 		echo "To resolve this:"; \