From eae757843771d4b5e95842fea9ae6149baeab5c3 Mon Sep 17 00:00:00 2001
From: rillig <rillig@NetBSD.org>
Date: Sat, 1 Jun 2024 11:06:17 +0000
Subject: [PATCH] tests/make: cover purging the realpath cache

In purge_relative_cached_realpaths, the hash table containing the cache
is modified while being iterated, which needs extra care, so add a test
that covers this code in at least a single simple scenario.
---
 usr.bin/make/unit-tests/varname-dot-objdir.exp |  1 +
 usr.bin/make/unit-tests/varname-dot-objdir.mk  | 11 +++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/usr.bin/make/unit-tests/varname-dot-objdir.exp b/usr.bin/make/unit-tests/varname-dot-objdir.exp
index 39a9383953dd..430e2c898172 100644
--- a/usr.bin/make/unit-tests/varname-dot-objdir.exp
+++ b/usr.bin/make/unit-tests/varname-dot-objdir.exp
@@ -1 +1,2 @@
+: purge-cache was reached.
 exit status 0
diff --git a/usr.bin/make/unit-tests/varname-dot-objdir.mk b/usr.bin/make/unit-tests/varname-dot-objdir.mk
index e662e8ac56fa..0f53165bba41 100644
--- a/usr.bin/make/unit-tests/varname-dot-objdir.mk
+++ b/usr.bin/make/unit-tests/varname-dot-objdir.mk
@@ -1,8 +1,15 @@
-# $NetBSD: varname-dot-objdir.mk,v 1.2 2020/08/16 14:25:16 rillig Exp $
+# $NetBSD: varname-dot-objdir.mk,v 1.3 2024/06/01 11:06:17 rillig Exp $
 #
 # Tests for the special .OBJDIR variable.
 
 # TODO: Implementation
 
 all:
-	@:;
+	# Add an entry to the cached_realpath table, to test cleaning up
+	# that table in purge_relative_cached_realpaths.
+	# Having a ':=' assignment in the command line is construed but works
+	# well enough to reach the code.
+	@${MAKE} -f ${MAKEFILE} 'VAR:=$${:U.:tA}' purge-cache
+
+purge-cache:
+	: ${.TARGET} was reached.