avoid duplicated logic and safe error handling

this avoids a potential panic for an out of workspace condition.

Also, we move error handling to a place where it is much simpler

src/vdp_pesi.c

@@ -1160,36 +1160,22 @@ vped_close_vdp(struct req *req, int skip, const struct vdp *vdp)
 	vdc->nxt = nxt;
 }
 
-static int
-push_vdps(struct req *req, struct nexus_gzip *gz, int obj_gzipped)
+static void
+push_vdps(struct req *req, struct vped_gzgz_priv *vgzgz, struct nexus_gzip *gz)
 {
-	struct vped_gzgz_priv *vgzgz;
-
-	CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
-	CHECK_OBJ_NOTNULL(req->objcore, OBJCORE_MAGIC);
-	CHECK_OBJ_NOTNULL(req->wrk, WORKER_MAGIC);
-
-	if (gz->is && obj_gzipped && !(req->res_mode & RES_ESI)) {
-		/* A gzip'ed include which is not ESI processed */
-
-		VSLdbg(req, "push_vdps: pushing gzgz");
-		if ((vgzgz = WS_Alloc(req->ws, sizeof(*vgzgz))) == NULL) {
-			VSLb(req->vsl, SLT_Error,
-			     "Insufficient workspace for ESI gzip data");
-			return (-1);
-		}
-		INIT_OBJ(vgzgz, VPED_GZGZ_PRIV_MAGIC);
-		vgzgz->gz = gz;
+	if (vgzgz != NULL) {
+		AZ(gz);
 		AZ(VDP_Push(req, &vped_gzgz, vgzgz));
 	}
-	else if (gz->is && !obj_gzipped) {
-		VSLdbg(req, "push_vdps: pushing pretend_gz");
-		/* Non-Gzip'ed include in gzip'ed parent */
+	else if (gz != NULL) {
+		AZ(vgzgz);
 		AZ(VDP_Push(req, &vped_pretend_gz, gz));
 	}
-	// else just push to parent
-
-	return (0);
+	else {
+		AZ(vgzgz);
+		AZ(gz);
+	}
+	return;
 }
 
 static void v_matchproto_(vtr_deliver_f)
@@ -1200,6 +1186,7 @@ vped_deliver(struct req *req, struct boc *boc, int wantbody)
 	struct bytes_tree *tree;
 	struct node *node, *parent;
 	struct nexus_gzip *gz;
+	struct vped_gzgz_priv *vgzgz = NULL;
 
 	VSLdbgv(req, "vped_deliver: req=%p boc=%p wantbody=%d", req, boc,
 		wantbody);
@@ -1249,6 +1236,25 @@ vped_deliver(struct req *req, struct boc *boc, int wantbody)
 			VDP_close(req);
 			return;
 		}
+
+		vgzgz = WS_Alloc(req->ws, sizeof *vgzgz);
+		if (vgzgz == NULL) {
+			VSLb(req->vsl, SLT_Error,
+			     "Insufficient workspace for ESI gzip data");
+			VDP_close(req);
+			return;
+		}
+		INIT_OBJ(vgzgz, VPED_GZGZ_PRIV_MAGIC);
+		vgzgz->gz = gz;
+		gz = NULL;
+	}
+	else if (gz->is && !obj_gzipped) {
+		AZ(vgzgz);
+		AN(gz);
+	}
+	else {
+		AZ(vgzgz);
+		gz = NULL;
 	}
 
 	if (obj_final && !obj_esi && (pesi->flags & PF_CFG_BLOCK_FINAL) == 0) {
@@ -1257,7 +1263,7 @@ vped_deliver(struct req *req, struct boc *boc, int wantbody)
 		VDP_Push(req, &VDP_pesi_buf, pesi);
 		AN(parent);
 		assert(parent->type == T_NEXUS);
-		AZ(push_vdps(req, gz, obj_gzipped));
+		push_vdps(req, vgzgz, gz);
 		AZ(VDP_Push(req, &vped_to_parent, parent->nexus.req));
 
 		(void)VDP_DeliverObj(req);
@@ -1271,7 +1277,7 @@ vped_deliver(struct req *req, struct boc *boc, int wantbody)
 	else if (obj_final && !obj_esi) {
 		VSLdbg(req, "vped_deliver: T_FINAL");
 
-		AZ(push_vdps(req, gz, obj_gzipped));
+		push_vdps(req, vgzgz, gz);
 		AZ(VDP_Push(req, &vped_to_parent, parent->nexus.req));
 
 		node_mutate_prep(tree, node);
@@ -1311,7 +1317,7 @@ vped_deliver(struct req *req, struct boc *boc, int wantbody)
 		VSLdbg(req, "vped_deliver: T_SUBREQ");
 
 		AZ(req->objcore->flags & OC_F_FINAL);
-		AZ(push_vdps(req, gz, obj_gzipped));
+		push_vdps(req, vgzgz, gz);
 		AZ(VDP_Push(req, &vped_to_parent, parent->nexus.req));
 
 		node_mutate_prep(tree, node);
@@ -1344,7 +1350,7 @@ vped_deliver(struct req *req, struct boc *boc, int wantbody)
 	VSLdbg(req, "vped_deliver: ESI");
 
 	VDP_Push(req, &VDP_pesi_buf, pesi);
-	AZ(push_vdps(req, gz, obj_gzipped));
+	push_vdps(req, vgzgz, gz);
 	AN(parent);
 	AZ(VDP_Push(req, &vped_to_parent, parent->nexus.req));