Update to Go 1.20 and fix rand-related issues.

.github/workflows/release.yml

@@ -13,7 +13,7 @@ jobs:
       - name: Install Go
         uses: actions/setup-go@v2
         with:
-          go-version: 1.18.x
+          go-version: 1.20.x
 
       - name: Check out code
         uses: actions/checkout@v2

.github/workflows/test.yml

@@ -7,7 +7,7 @@ jobs:
     - name: Install Go
       uses: actions/setup-go@v2
       with:
-        go-version: 1.18.x
+        go-version: 1.20.x
     - name: Check out code
       uses: actions/checkout@v2
     - name: Build

main.go

@@ -1,14 +1,15 @@
 // Copyright 2014 Team 254. All Rights Reserved.
 // Author: pat@patfairbank.com (Patrick Fairbank)
 
+// Go version 1.20 or newer is required due to how it initializes the PRNG.
+//go:build go1.20
+
 package main
 
 import (
 	"github.com/Team254/cheesy-arena-lite/field"
 	"github.com/Team254/cheesy-arena-lite/web"
 	"log"
-	"math/rand"
-	"time"
 )
 
 const eventDbPath = "./event.db"
@@ -16,8 +17,6 @@ const httpPort = 8080
 
 // Main entry point for the application.
 func main() {
-	rand.Seed(time.Now().UnixNano())
-
 	arena, err := field.NewArena(eventDbPath)
 	if err != nil {
 		log.Fatalln("Error during startup: ", err)

tournament/qualification_rankings_test.go

@@ -7,10 +7,12 @@ import (
 	"github.com/Team254/cheesy-arena-lite/game"
 	"github.com/Team254/cheesy-arena-lite/model"
 	"github.com/stretchr/testify/assert"
+	"math/rand"
 	"testing"
 )
 
 func TestCalculateRankings(t *testing.T) {
+	rand.Seed(1)
 	database := setupTestDb(t)
 
 	setupMatchResultsForRankings(database)