From 0437acd41da9b4425102f2c4f8390edea2b08b28 Mon Sep 17 00:00:00 2001
From: Marten Seemann <martenseemann@gmail.com>
Date: Sun, 7 Feb 2021 19:57:42 +0800
Subject: [PATCH] set the qlogged quic-go version when building the interop
 runner image

---
 interop/Dockerfile |  4 ++--
 qlog/qlog.go       | 12 +++++++++++-
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/interop/Dockerfile b/interop/Dockerfile
index 76686d311..380aad375 100644
--- a/interop/Dockerfile
+++ b/interop/Dockerfile
@@ -19,8 +19,8 @@ RUN git clone https://github.com/lucas-clemente/quic-go && \
 WORKDIR /quic-go
 
 RUN git rev-parse HEAD > commit.txt
-RUN go build -o server interop/server/main.go && \
- go build -o client interop/client/main.go
+RUN go build -o server -ldflags="-X github.com/lucas-clemente/quic-go/qlog.quicGoVersion=$(git describe --always --long --dirty)" interop/server/main.go
+RUN go build -o client -ldflags="-X github.com/lucas-clemente/quic-go/qlog.quicGoVersion=$(git describe --always --long --dirty)" interop/client/main.go
 
 
 FROM martenseemann/quic-network-simulator-endpoint:latest
diff --git a/qlog/qlog.go b/qlog/qlog.go
index a53ceeac9..d28700dd8 100644
--- a/qlog/qlog.go
+++ b/qlog/qlog.go
@@ -18,9 +18,15 @@ import (
 	"github.com/francoispqt/gojay"
 )
 
+// Setting of this only works when quic-go is used as a library.
+// When building a binary from this repository, the version can be set using the following go build flag:
+// -ldflags="-X github.com/lucas-clemente/quic-go/qlog.quicGoVersion=foobar"
 var quicGoVersion = "(devel)"
 
 func init() {
+	if quicGoVersion != "(devel)" { // variable set by ldflags
+		return
+	}
 	info, ok := debug.ReadBuildInfo()
 	if !ok { // no build info available. This happens when quic-go is not used as a library.
 		return
@@ -29,7 +35,11 @@ func init() {
 		if d.Path == "github.com/lucas-clemente/quic-go" {
 			quicGoVersion = d.Version
 			if d.Replace != nil {
-				quicGoVersion += " (replaced)"
+				if len(d.Replace.Version) > 0 {
+					quicGoVersion = d.Version
+				} else {
+					quicGoVersion += " (replaced)"
+				}
 			}
 			break
 		}