Defer closing the gitrepo until the end of the wrapped context functions (#15653)

There was a mistake in #15372 where deferral of gitrepo close occurs before it should.

This PR fixes this.

Signed-off-by: Andrew Thornton <art27@cantab.net>

modules/web/route.go

@@ -5,6 +5,7 @@
 package web
 
 import (
+	goctx "context"
 	"fmt"
 	"net/http"
 	"reflect"
@@ -27,6 +28,7 @@ func Wrap(handlers ...interface{}) http.HandlerFunc {
 		switch t := handler.(type) {
 		case http.HandlerFunc, func(http.ResponseWriter, *http.Request),
 			func(ctx *context.Context),
+			func(ctx *context.Context) goctx.CancelFunc,
 			func(*context.APIContext),
 			func(*context.PrivateContext),
 			func(http.Handler) http.Handler:
@@ -48,6 +50,15 @@ func Wrap(handlers ...interface{}) http.HandlerFunc {
 				if r, ok := resp.(context.ResponseWriter); ok && r.Status() > 0 {
 					return
 				}
+			case func(ctx *context.Context) goctx.CancelFunc:
+				ctx := context.GetContext(req)
+				cancel := t(ctx)
+				if cancel != nil {
+					defer cancel()
+				}
+				if ctx.Written() {
+					return
+				}
 			case func(ctx *context.Context):
 				ctx := context.GetContext(req)
 				t(ctx)
@@ -94,6 +105,23 @@ func Middle(f func(ctx *context.Context)) func(netx http.Handler) http.Handler {
 	}
 }
 
+// MiddleCancel wrap a context function as a chi middleware
+func MiddleCancel(f func(ctx *context.Context) goctx.CancelFunc) func(netx http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
+			ctx := context.GetContext(req)
+			cancel := f(ctx)
+			if cancel != nil {
+				defer cancel()
+			}
+			if ctx.Written() {
+				return
+			}
+			next.ServeHTTP(ctx.Resp, ctx.Req)
+		})
+	}
+}
+
 // MiddleAPI wrap a context function as a chi middleware
 func MiddleAPI(f func(ctx *context.APIContext)) func(netx http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
@@ -163,6 +191,8 @@ func (r *Route) Use(middlewares ...interface{}) {
 				r.R.Use(t)
 			case func(*context.Context):
 				r.R.Use(Middle(t))
+			case func(*context.Context) goctx.CancelFunc:
+				r.R.Use(MiddleCancel(t))
 			case func(*context.APIContext):
 				r.R.Use(MiddleAPI(t))
 			default: