Retire VCL_EVENT_USE

It was decided during VDD15Q3 but this change didn't make it before the
4.1.0 release. It is kept in the 4.1 series but documented as deprecated
and can now be retired as discussed during VDD15Q4.

bin/varnishd/cache/cache_vcl.c

@@ -475,11 +475,10 @@ vcl_failsafe_event(VRT_CTX, enum vcl_event_e ev)
 	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
 	AN(ctx->handling);
 	AN(ctx->vcl);
-	assert(ev == VCL_EVENT_COLD || ev == VCL_EVENT_DISCARD ||
-	    ev == VCL_EVENT_USE);
+	assert(ev == VCL_EVENT_COLD || ev == VCL_EVENT_DISCARD);
 
 	if (ctx->vcl->conf->event_vcl(ctx, ev) != 0)
-		WRONG("A VMOD cannot fail USE, COLD or DISCARD events");
+		WRONG("A VMOD cannot fail COLD or DISCARD events");
 }
 
 static void
@@ -784,8 +783,6 @@ static void __match_proto__(cli_func_t)
 ccf_config_use(struct cli *cli, const char * const *av, void *priv)
 {
 	struct vcl *vcl;
-	struct vrt_ctx ctx;
-	unsigned hand = 0;
 
 	ASSERT_CLI();
 	AN(cli);
@@ -793,10 +790,6 @@ ccf_config_use(struct cli *cli, const char * const *av, void *priv)
 	vcl = vcl_find(av[2]);
 	AN(vcl);				// MGT ensures this
 	assert(vcl->temp == VCL_TEMP_WARM);	// MGT ensures this
-	INIT_OBJ(&ctx, VRT_CTX_MAGIC);
-	ctx.handling = &hand;
-	ctx.vcl = vcl;
-	vcl_failsafe_event(&ctx, VCL_EVENT_USE);
 	Lck_Lock(&vcl_mtx);
 	vcl_active = vcl;
 	Lck_Unlock(&vcl_mtx);

doc/sphinx/reference/vmod.rst

@@ -426,10 +426,6 @@ In the case where properly releasing resources may take some time, you can
 opt for an asynchronous worker, either by spawning a thread and tracking it, or
 by using Varnish's worker pools.
 
-There is also a ``VCL_EVENT_USE`` event. Please note that this event is now
-deprecated and may be removed in a future release. A warm VCL should be ready
-to use so no additional task should be postponed at use time.
-
 When to lock, and when not to lock
 ==================================
 

lib/libvcc/generate.py

@@ -1027,7 +1027,6 @@ struct worker;
 enum vcl_event_e {
 	VCL_EVENT_LOAD,
 	VCL_EVENT_WARM,
-	VCL_EVENT_USE,
 	VCL_EVENT_COLD,
 	VCL_EVENT_DISCARD,
 };

lib/libvcc/vcc_compile.c

@@ -326,8 +326,7 @@ EmitCoordinates(const struct vcc *tl, struct vsb *vsb)
  * Init/Fini/Event
  *
  * We call DISCARD and COLD events in the opposite order of LOAD and
- * WARM. The child will panic if a USE event fails, since a WARM event
- * leads to a usable state.
+ * WARM.
  */
 
 static void
@@ -403,24 +402,6 @@ EmitInitFini(const struct vcc *tl)
 		Fc(tl, 0, "\treturn (0);\n");
 		Fc(tl, 0, "}\n");
 
-		/*
-		 * USE (deprecated)
-		 */
-		Fc(tl, 0, "\nstatic int\n");
-		Fc(tl, 0, "VGC_Use(VRT_CTX, enum vcl_event_e ev)\n{\n\n");
-
-		VTAILQ_FOREACH(p, &tl->inifin, list) {
-			assert(p->n > 0);
-			if (VSB_len(p->event)) {
-				Fc(tl, 0, "\t/* %u */\n", p->n);
-				Fc(tl, 0, "\tif (%s)\n", VSB_data(p->event));
-				Fc(tl, 0, "\t\treturn (1);\n\n");
-			}
-		}
-
-		Fc(tl, 0, "\treturn (0);\n");
-		Fc(tl, 0, "}\n");
-
 		/*
 		 * COLD
 		 */
@@ -453,8 +434,6 @@ EmitInitFini(const struct vcc *tl)
 	if (has_event) {
 		Fc(tl, 0, "\tif (ev == VCL_EVENT_WARM)\n");
 		Fc(tl, 0, "\t\treturn(VGC_Warmup(ctx, ev));\n");
-		Fc(tl, 0, "\tif (ev == VCL_EVENT_USE)\n");
-		Fc(tl, 0, "\t\treturn(VGC_Use(ctx, ev));\n");
 		Fc(tl, 0, "\tif (ev == VCL_EVENT_COLD)\n");
 		Fc(tl, 0, "\t\treturn(VGC_Cooldown(ctx, ev));\n");
 	}