Use $Restrict

src/vdfp_pipe.c

 /*-
- * Copyright (c) 2019 UPLEX Nils Goroll Systemoptimierung
+ * Copyright 2019, 2023 UPLEX Nils Goroll Systemoptimierung
  * All rights reserved
  *
  * Author: Geoffrey Simmons <geoffrey.simmons@uplex.de>
@@ -793,11 +793,7 @@ vmod_vdp_arg(VRT_CTX, struct VPFX(pipe_vdp) *obj, VCL_STRING arg)
 	CHECK_OBJ_NOTNULL(ctx->ws, WS_MAGIC);
 	CHECK_OBJ_NOTNULL(obj, PIPE_VDP_MAGIC);
 
-	if (!(ctx->method & (VCL_MET_INIT | VCL_MET_DELIVER))) {
-		VDPFAIL(ctx, "%s.arg(): may only be called in vcl_init or "
-			"vcl_deliver", obj->name);
-		return;
-	}
+	AN(ctx->method & (VCL_MET_INIT | VCL_MET_DELIVER));
 
 	if (arg == NULL) {
 		VDPFAIL(ctx, "%s.arg(): arg is NULL", obj->name);
@@ -871,11 +867,7 @@ vmod_vdp_setenv(VRT_CTX, struct VPFX(pipe_vdp) *obj, VCL_STRING var,
 	CHECK_OBJ_NOTNULL(ctx->ws, WS_MAGIC);
 	CHECK_OBJ_NOTNULL(obj, PIPE_VDP_MAGIC);
 
-	if (!(ctx->method & (VCL_MET_INIT | VCL_MET_DELIVER))) {
-		VDPFAIL(ctx, "%s.setenv(): may only be called in vcl_init or "
-			"vcl_deliver", obj->name);
-		return;
-	}
+	AN(ctx->method & (VCL_MET_INIT | VCL_MET_DELIVER));
 
 	if (var == NULL || *var == '\0') {
 		VDPFAIL(ctx, "%s.setenv(): var is empty", obj->name);

src/vdfp_pipe.vcc

@@ -91,8 +91,7 @@ For example, to execute the VDPs shown above after ESI processing::
 $Object vdp(STRING path, STRING name=0, BYTES bufsz=0, DURATION timeout=60)
 
 Define a VDP that transforms client responses by piping them through
-the program located at ``path``. The constructor may only be called in
-``vcl_init``.
+the program located at ``path``.
 
 The ``path`` parameter is required, MAY NOT be empty, and MUST specify
 the absolute location of the file; the ``PATH`` environment variable
@@ -184,14 +183,16 @@ A complete example::
 $Method VOID .arg(STRING)
 
 The ``.arg()`` method sets a command-line argument to be used with a
-program. The method MAY NOT be called in any VCL subroutine besides
-``vcl_init`` or ``vcl_deliver``. Invocations of ``.arg()`` in
-``vcl_init`` set arguments to be used globally in the VCL
-instance. Invocations in ``vcl_deliver`` set arguments to be used for
-a single client response, overriding any arguments that may have been
-set in ``vcl_init`` For example, you can call ``.arg()`` in
-``vcl_deliver`` if the arguments to be used are not known until
-runtime.
+program.
+
+$Restrict vcl_init vcl_deliver
+
+Invocations of ``.arg()`` in ``vcl_init`` set arguments to be used
+globally in the VCL instance. Invocations in ``vcl_deliver`` set
+arguments to be used for a single client response, overriding any
+arguments that may have been set in ``vcl_init`` For example, you can
+call ``.arg()`` in ``vcl_deliver`` if the arguments to be used are not
+known until runtime.
 
 The parameter in ``.arg()`` MAY be empty (if you need the empty string
 as a CLI argument), but MAY NOT be NULL (for example, it may not be
@@ -217,7 +218,7 @@ The CLI arguments for a command are ordered as the order in which
 		tr.arg(resp.http.X-TR-Set2);
 	}
 	set resp.filters = "tr";
-  }  
+  }
 
 You can leave ``.arg()`` out of ``vcl_init``, and only call it in
 ``vcl_deliver``, if the values of the arguments are only known at
@@ -250,11 +251,12 @@ $Method VOID .setenv(STRING var, STRING value, BOOL overwrite=1)
 Set the environment variable ``var`` to ``value`` in the invoked
 process.
 
-Like ``.arg()``, ``.setenv()`` MAY NOT be called in any VCL subroutine
-besides ``vcl_init`` or ``vcl_deliver``. Settings in ``vcl_init`` are
-global for the VCL instance, while settings in ``vcl_deliver`` are
-valid for a single client response (for use cases where the
-environment settings are not known until runtime).
+$Restrict vcl_init vcl_deliver
+
+Settings in ``vcl_init`` are global for the VCL instance, while
+settings in ``vcl_deliver`` are valid for a single client response
+(for use cases where the environment settings are not known until
+runtime).
 
 Currently, any invocation of ``.setenv()`` in ``vcl_deliver`` cancels
 all environment settings specified in ``vcl_init`` for the current