[SV 64107] Disable builtins immediately on -R or -r

Disable builtin variables and rules immediately, when -R or -r is
added to MAKEFLAGS inside the makefile.

* src/main.c (disable_builtins): Add new function disable_builtins().
(main): Call disable_builtins().
(reset_makeflags): Call disable_builtins().
* tests/scripts/options/dash-r: Add tests.
* tests/scripts/variables/MAKEFLAGS: Update tests.

3 files changed, 100 insertions, 23 deletions

diff --git a/src/main.c b/src/main.c
index 6a94cfdb..8215ed78 100644
--- a/src/main.c
+++ b/src/main.c
@@ -101,6 +101,7 @@ static void decode_switches (int argc, const char **argv,
                              enum variable_origin origin);
 static void decode_env_switches (const char *envar, size_t len,
                                  enum variable_origin origin);
+static void disable_builtins ();
 static char *quote_for_env (char *out, const char *in);
 static void initialize_global_hash_tables (void);
 
@@ -180,6 +181,8 @@ int question_flag = 0;
 
 int no_builtin_rules_flag = 0;
 int no_builtin_variables_flag = 0;
+static int old_builtin_rules_flag;
+static int old_builtin_variables_flag;
 
 /* Nonzero means all variables are automatically exported.  */
 
@@ -2052,9 +2055,9 @@ main (int argc, char **argv, char **envp)
     }
 
   {
-    int old_builtin_rules_flag = no_builtin_rules_flag;
-    int old_builtin_variables_flag = no_builtin_variables_flag;
     int old_arg_job_slots = arg_job_slots;
+    old_builtin_rules_flag = no_builtin_rules_flag;
+    old_builtin_variables_flag = no_builtin_variables_flag;
 
     /* Read all the makefiles.  */
     read_files = read_all_makefiles (makefiles == 0 ? 0 : makefiles->list);
@@ -2100,24 +2103,7 @@ main (int argc, char **argv, char **envp)
     make_sync.syncout = syncing;
     OUTPUT_SET (&make_sync);
 
-    /* If -R was given, set -r too (doesn't make sense otherwise!)  */
-    if (no_builtin_variables_flag)
-      no_builtin_rules_flag = 1;
-
-    /* If we've disabled builtin rules, get rid of them.  */
-    if (no_builtin_rules_flag && ! old_builtin_rules_flag)
-      {
-        if (suffix_file->builtin)
-          {
-            free_dep_chain (suffix_file->deps);
-            suffix_file->deps = 0;
-          }
-        define_variable_cname ("SUFFIXES", "", o_default, 0);
-      }
-
-    /* If we've disabled builtin variables, get rid of them.  */
-    if (no_builtin_variables_flag && ! old_builtin_variables_flag)
-      undefine_default_variables ();
+    disable_builtins ();
   }
 
 #if MK_OS_W32
@@ -3094,6 +3080,7 @@ reset_makeflags (enum variable_origin origin)
 {
   decode_env_switches (STRING_SIZE_TUPLE(MAKEFLAGS_NAME), origin);
   construct_include_path (include_dirs ? include_dirs->list : NULL);
+  disable_builtins ();
   define_makeflags (rebuilding_makefiles);
 }
 
@@ -3451,6 +3438,37 @@ quote_for_env (char *out, const char *in)
   return out;
 }
 
+/* Disable builtin variables and rules, if -R or -r is specified.
+ * This function is called at parse time whenever MAKEFLAGS is modified and
+ * also when the parsing phase is over.  */
+
+static
+void disable_builtins ()
+{
+    /* If -R was given, set -r too (doesn't make sense otherwise!)  */
+    if (no_builtin_variables_flag)
+      no_builtin_rules_flag = 1;
+
+    /* If we've disabled builtin rules, get rid of them.  */
+    if (no_builtin_rules_flag && ! old_builtin_rules_flag)
+      {
+        old_builtin_rules_flag = 1;
+        if (suffix_file->builtin)
+          {
+            free_dep_chain (suffix_file->deps);
+            suffix_file->deps = 0;
+          }
+        define_variable_cname ("SUFFIXES", "", o_default, 0);
+      }
+
+    /* If we've disabled builtin variables, get rid of them.  */
+    if (no_builtin_variables_flag && ! old_builtin_variables_flag)
+      {
+        old_builtin_variables_flag = 1;
+        undefine_default_variables ();
+      }
+}
+
 /* Define the MAKEFLAGS and MFLAGS variables to reflect the settings of the
    command switches. Always include options with args.
    Don't include options with the 'no_makefile' flag set if MAKEFILE.  */
diff --git a/tests/scripts/options/dash-r b/tests/scripts/options/dash-r
index 7157f715..16eda104 100644
--- a/tests/scripts/options/dash-r
+++ b/tests/scripts/options/dash-r
@@ -2,8 +2,6 @@
 
 $description = "Test removing default rules and variables";
 
-$details = "DETAILS";
-
 touch('xxx.c');
 
 # Simple check
@@ -41,4 +39,65 @@ MAKEFLAGS := -R
 all: hello.o
 !, '', "#MAKE#: *** No rule to make target 'hello.o', needed by 'all'.  Stop.", 512);
 
+my @flavors = ('=', ':=', ':::=', '+=');
+
+# sv 64107.
+
+# Use $answer to test that -R in the makefile has the same effect as -R on the
+# command line.
+
+my $answer = "at parse time TEX=\nat build time TEX=\n#MAKE#: 'all' is up to date.\n";
+
+# Subtest 1.
+# First run with -R command line switch.
+
+for my $fl (@flavors) {
+run_make_test("
+\$(info at parse time TEX=\$(TEX))
+all:; \$(info at build time TEX=\$(TEX))
+", '-R', "$answer");
+}
+
+# Subtest 2.
+# Set -R in the makefile.
+# Also, test that setting -R in MAKEFLAGS takes effect immediately.
+
+for my $fl (@flavors) {
+run_make_test("
+\$(info at start time TEX=\$(TEX))
+MAKEFLAGS ${fl} -R
+\$(info at parse time TEX=\$(TEX))
+all:; \$(info at build time TEX=\$(TEX))
+", '', "at start time TEX=tex\n$answer");
+}
+
+# Same as above, but also set TEX conditionally.
+
+$answer = "at parse time TEX=hello\nat build time TEX=hello\n#MAKE#: 'all' is up to date.\n";
+
+# Subtest 3.
+# -R on the command line.
+
+for my $fl (@flavors) {
+run_make_test("
+TEX ?= hello
+\$(info at parse time TEX=\$(TEX))
+all:; \$(info at build time TEX=\$(TEX))
+", '-R', "$answer");
+}
+
+# Subtest 4.
+# -R in the makefile.
+
+for my $fl (@flavors) {
+run_make_test("
+\$(info at start time TEX=\$(TEX))
+MAKEFLAGS ${fl} -R
+TEX ?= hello
+\$(info at parse time TEX=\$(TEX))
+all:; \$(info at build time TEX=\$(TEX))
+", '', "at start time TEX=tex\n$answer");
+}
+
+
 1;
diff --git a/tests/scripts/variables/MAKEFLAGS b/tests/scripts/variables/MAKEFLAGS
index fc18d650..aab4a0e1 100644
--- a/tests/scripts/variables/MAKEFLAGS
+++ b/tests/scripts/variables/MAKEFLAGS
@@ -297,7 +297,7 @@ MAKEFLAGS${fl}R
 all:; \$(info \$(MAKEFLAGS))
 ", 'bye=moon',
 "$answer
-R$answer
+rR$answer
 rR$answer
 #MAKE#: 'all' is up to date.\n");
 }