[master] 4e316c260 vmod: Objects can have methods named like constructors

[Dridi Boukelmoune]

commit 4e316c260a02c142c1a94a3f8efd7b5e445b7177
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Wed Sep 30 11:38:19 2020 +0200

    vmod: Objects can have methods named like constructors
    
    I came across a VMOD that has a method named like the constructor to
    conceptually reinitialize the object's state. That's an implementation
    detail of the VMOD in question and arguably undefined behavior in
    Varnish.
    
    In order to not accidentally break this assumption, add some test
    coverage and document this possibility.

diff --git a/bin/varnishtest/tests/m00000.vtc b/bin/varnishtest/tests/m00000.vtc
index 5a861c680..a64fa7d06 100644
--- a/bin/varnishtest/tests/m00000.vtc
+++ b/bin/varnishtest/tests/m00000.vtc
@@ -36,6 +36,7 @@ varnish v1 -vcl+backend {
 
 	sub vcl_init {
 		new objx = dbg.obj();
+		objx.obj();
 		dbg.vsc_new();
 		call log;
 	}
diff --git a/doc/sphinx/reference/vmod.rst b/doc/sphinx/reference/vmod.rst
index f4edad883..4497fe095 100644
--- a/doc/sphinx/reference/vmod.rst
+++ b/doc/sphinx/reference/vmod.rst
@@ -211,6 +211,13 @@ after the instantiation)::
 		foo.method(...);
 	}
 
+Nothing prevents a method to be named like the constructor and the
+meaning of such a method is up to the vmod author::
+
+	$Object foo(...)
+	$Method .bar(...)
+	$Method .foo(...)
+
 Object instances are represented as pointers to vmod-implemented C
 structs. Varnish only provides space to store the address of object
 instances and ensures that the right object address gets passed to C
diff --git a/lib/libvmod_debug/vmod_debug.vcc b/lib/libvmod_debug/vmod_debug.vcc
index 094db5311..f565b456c 100644
--- a/lib/libvmod_debug/vmod_debug.vcc
+++ b/lib/libvmod_debug/vmod_debug.vcc
@@ -74,6 +74,10 @@ $Method VOID .enum(ENUM { phk, des, kristian, mithrandir, martin })
 Testing that enums work as part of object and that the parser isn't
 (too) buggy.
 
+$Method VOID .obj()
+
+Covering the fact that a method can be named like the constructor.
+
 $Method STRING .string()
 
 getter for string
diff --git a/lib/libvmod_debug/vmod_debug_obj.c b/lib/libvmod_debug/vmod_debug_obj.c
index 8efd6ad50..8bc328290 100644
--- a/lib/libvmod_debug/vmod_debug_obj.c
+++ b/lib/libvmod_debug/vmod_debug_obj.c
@@ -82,6 +82,14 @@ xyzzy_obj_enum(VRT_CTX, struct xyzzy_debug_obj *o, VCL_ENUM e)
 	assert(!strcmp(e, "martin"));
 }
 
+VCL_VOID v_matchproto_(td_xyzzy_obj_enum)
+xyzzy_obj_obj(VRT_CTX, struct xyzzy_debug_obj *o)
+{
+
+	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
+	CHECK_OBJ_NOTNULL(o, VMOD_DEBUG_OBJ_MAGIC);
+}
+
 VCL_STRING v_matchproto_()
 xyzzy_obj_foo(VRT_CTX, struct xyzzy_debug_obj *o, VCL_STRING s)
 {