From e9dd614d73fc625845a0de089edae3a8433e30c1 Mon Sep 17 00:00:00 2001
From: Dmitry Goncharov <dgoncharov@users.sf.net>
Date: Mon, 20 Feb 2023 15:17:24 -0500
Subject: [SV 63821] Don't set up default suffix rules if makefile sets -r

When built-in rules are disabled by adding -r to MAKEFLAGS in the
makefile, don't add suffix rules at all so that if suffixes are
added back via .SUFFIXES, the rules are still not there.

* src/main.c (main): Set default suffix rules after parsing makefiles.
* src/default.c (install_default_suffix_rules): Install a default
suffix rule only if there is no user defined rule.
* tests/scripts/features/suffixrules: Add tests.
---
 src/default.c                      | 20 ++++++------
 src/main.c                         | 12 +++----
 tests/scripts/features/suffixrules | 65 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 81 insertions(+), 16 deletions(-)

diff --git a/src/default.c b/src/default.c
index ffb5f98c..e396269b 100644
--- a/src/default.c
+++ b/src/default.c
@@ -707,7 +707,7 @@ set_default_suffixes (void)
    installed after.  */
 
 void
-install_default_suffix_rules (void)
+install_default_suffix_rules ()
 {
   const char **s;
 
@@ -717,14 +717,16 @@ install_default_suffix_rules (void)
   for (s = default_suffix_rules; *s != 0; s += 2)
     {
       struct file *f = enter_file (strcache_add (s[0]));
-      /* This function should run before any makefile is parsed.  */
-      assert (f->cmds == 0);
-      f->cmds = xmalloc (sizeof (struct commands));
-      f->cmds->fileinfo.filenm = 0;
-      f->cmds->commands = xstrdup (s[1]);
-      f->cmds->command_lines = 0;
-      f->cmds->recipe_prefix = RECIPEPREFIX_DEFAULT;
-      f->builtin = 1;
+      /* Install the default rule only if there is no user defined rule.  */
+      if (!f->cmds)
+        {
+          f->cmds = xmalloc (sizeof (struct commands));
+          f->cmds->fileinfo.filenm = NULL;
+          f->cmds->commands = xstrdup (s[1]);
+          f->cmds->command_lines = NULL;
+          f->cmds->recipe_prefix = RECIPEPREFIX_DEFAULT;
+          f->builtin = 1;
+        }
     }
 }
 
diff --git a/src/main.c b/src/main.c
index dde0d77d..e62aee60 100644
--- a/src/main.c
+++ b/src/main.c
@@ -2028,13 +2028,6 @@ main (int argc, char **argv, char **envp)
   /* Define the initial list of suffixes for old-style rules.  */
   set_default_suffixes ();
 
-  /* Define the file rules for the built-in suffix rules.  These will later
-     be converted into pattern rules.  We used to do this in
-     install_default_implicit_rules, but since that happens after reading
-     makefiles, it results in the built-in pattern rules taking precedence
-     over makefile-specified suffix rules, which is wrong.  */
-  install_default_suffix_rules ();
-
   /* Define some internal and special variables.  */
   define_automatic_variables ();
 
@@ -2280,6 +2273,11 @@ main (int argc, char **argv, char **envp)
 
   define_makeflags (0);
 
+  /* Define the file rules for the built-in suffix rules.  These will later
+     be converted into pattern rules.  */
+
+  install_default_suffix_rules ();
+
   /* Make each 'struct goaldep' point at the 'struct file' for the file
      depended on.  Also do magic for special targets.  */
 
diff --git a/tests/scripts/features/suffixrules b/tests/scripts/features/suffixrules
index b8f46526..5e969b2a 100644
--- a/tests/scripts/features/suffixrules
+++ b/tests/scripts/features/suffixrules
@@ -95,5 +95,70 @@ run_make_test(undef,
 
 unlink('foo.baz', 'foo.biz', 'foo.bar');
 
+
+touch('hello.c');
+unlink('hello.o');
+
+# sv 63821.
+# Default suffix rule .c.o.
+
+run_make_test('all: hello.o', 'COMPILE.c=@echo OUTPUT_OPTION=', 'hello.c');
+
+# User defined rules beat built-in rules.
+
+run_make_test(q!
+all: hello.o
+.c.o:; $(info $@ user defined .c.o rule)
+!, '', "hello.o user defined .c.o rule\n#MAKE#: Nothing to be done for 'all'.\n");
+
+# sv 63821.
+# The same as above, but suffixes are cleared.
+
+run_make_test(q!
+all: hello.o
+.SUFFIXES:
+.c.o:; $(info $@ user defined .c.o rule)
+!, '', "#MAKE#: *** No rule to make target 'hello.o', needed by 'all'.  Stop.\n", 512);
+
+# sv 63821.
+# Suffixes are cleared and defined in the makefile.
+
+run_make_test(q!
+all: hello.o
+.SUFFIXES:
+.SUFFIXES: .c .o
+.c.o:; $(info $@ user defined .c.o rule)
+!, '', "hello.o user defined .c.o rule\n#MAKE#: Nothing to be done for 'all'.\n");
+
+# sv 63821.
+# When built-in rules are disabled, but certain suffixes are added to
+# .SUFFIXES, make should exit with the 'No rule...' error message.
+
+run_make_test(q!
+.SUFFIXES: .c .o
+all: hello.o
+!, '-r', "#MAKE#: *** No rule to make target 'hello.o', needed by 'all'.  Stop.\n", 512);
+
+# sv 63821.
+# Same as above, but this time built-in rules are disabled inside the makefile.
+
+run_make_test(q!
+MAKEFLAGS += -r
+.SUFFIXES: .c .o
+all: hello.o
+!, '', "#MAKE#: *** No rule to make target 'hello.o', needed by 'all'.  Stop.\n", 512);
+
+# sv 63821.
+# Same as above, but this time there is a rule.
+
+run_make_test(q!
+all: hello.o
+MAKEFLAGS += -r
+.SUFFIXES: .c .o
+.c.o:; $(info $@ user defined .c.o rule)
+!, '', "hello.o user defined .c.o rule\n#MAKE#: Nothing to be done for 'all'.\n");
+
+unlink('hello.c', 'hello.o');
+
 # Complete
 1;
-- 
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