Fix backward incompatibility of option.get if an argument is not added with args.add-arg.

When such an argument isn't registered we fail to check `ARGV` directly as a backup, for backward compatibility. This fixes that problem by checking if an argument is registered, and if not falling back on the direct `ARGV` check.

fixes #440

doc/src/history.adoc

@@ -1,6 +1,14 @@
 [[b2.history]]
 = History
 
+== Version 5.3.1
+
+Fix backward incompatibility of `option.get` if an argument is not added with
+`args.add-arg`. When such an argument isn't registered we fail to check `ARGV`
+directly as a backup, for backward compatibility. This fixes that problem by
+checking if an argument is registered, and if not falling back on the direct
+`ARGV` check.
+
 == Version 5.3.0
 
 Biggest changes for this release is the creation of two new toolsets: `ibmcxx`

src/build/version.jam

@@ -10,7 +10,7 @@ import numbers ;
 # Mirror engine JAM_VERSION
 .major = 5 ;
 .minor = 3 ;
-.patch = 0 ;
+.patch = 1 ;
 
 
 rule build ( )

src/engine/mod_args.cpp

@@ -35,10 +35,7 @@ struct args_reg
 	std::vector<std::string> args;
 	bool need_reparse = true;
 
-	args_reg()
-	{
-		cli.style_print_short_first();
-	}
+	args_reg() { cli.style_print_short_first(); }
 
 	void set_args(int argc, char ** argv)
 	{
@@ -105,6 +102,8 @@ struct args_reg
 			return globs.debug_configuration ? list_ref("true") : list_ref();
 		return {};
 	}
+
+	bool has_opt(const value_ref & name) { return (options.count(name) > 0); }
 };
 } // namespace
 
@@ -119,6 +118,8 @@ list_ref get_arg(const value_ref & name)
 	return args_reg::ref().get_opt(name);
 }
 
+bool has_arg(const value_ref & name) { return args_reg::ref().has_opt(name); }
+
 void set_args(int argc, char ** argv) { args_reg::ref().set_args(argc, argv); }
 
 lyra::cli & lyra_cli() { return args_reg::ref().cli; }

src/engine/mod_args.h

@@ -65,6 +65,21 @@ Retrieve the value of a previous specified command line argument.
 end::reference[] */
 list_ref get_arg(const value_ref & name);
 
+/* tag::reference[]
+
+== `b2::args::has_arg`
+
+====
+[horizontal]
+Jam:: `rule has-arg ( name )`
+{CPP}:: `bool has_arg(value_ref name);`
+====
+
+Checks if an argument was previously added.
+
+end::reference[] */
+bool has_arg(const value_ref & name);
+
 void set_args(int argc, char ** argv);
 lyra::cli & lyra_cli();
 void process_args(bool silent = false);
@@ -80,7 +95,8 @@ struct args_module : b2::bind::module_<args_module>
 		binder
 			.def(&add_arg, "add-arg",
 				"name" * _1 | "opts" * _1n | "help" * _1 | "flags" * _n)
-			.def(&get_arg, "get-arg", "name" * _1);
+			.def(&get_arg, "get-arg", "name" * _1)
+			.def(&has_arg, "has-arg", "name" * _1);
 		binder.eval(init_code);
 		binder.loaded();
 	}

src/engine/patchlevel.h

@@ -14,4 +14,4 @@ https://www.bfgroup.xyz/b2/LICENSE.txt)
 
 #define VERSION_MAJOR 5
 #define VERSION_MINOR 3
-#define VERSION_PATCH 0
+#define VERSION_PATCH 1

src/util/option.jam

@@ -18,6 +18,12 @@ rule set ( name : value ? )
 rule get ( name : default-value ? : implied-value ? )
 {
     local m = [ args.get-arg $(name) ] ;
+    # For backwards compat also check ARGV directly in case the arg has not been
+    # declared.
+    if ! $(m) && ! [ args.has-arg $(name) ]
+    {
+        m = [ MATCH --$(name)=(.*) : [ modules.peek : ARGV ] ] ;
+    }
     if $(m) && $(m) != true
     {
         return $(m[1]) ;