Code quality improvements

.github/workflows/main.yml

@@ -2,16 +2,37 @@ name: Go package
 on: [push]
 jobs:
   build:
+    name: 'Go Build (1.20)'
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-      - name: Setup Go
-        uses: actions/setup-go@v4
+      - uses: actions/setup-go@v4
         with:
-          go-version: '1.19'
+          go-version: '1.20'
       - name: Install dependencies
         run: go get .
-      - name: Build
-        run: go build
       - name: Test
-        run: go test
+        run: go test
+  static:
+    name: 'Go Static (1.20)'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v4
+        with:
+          go-version: '1.20'
+        run: 'go install honnef.co/go/tools/cmd/staticcheck@latest'
+      - run: 'go vet ./...'
+      - run: 'staticcheck ./...'
+  test:
+    name: 'Go Test (1.20)'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v4
+        with:
+          go-version: '1.20'
+      - name: Install dependencies
+        run: go get .
+      - name: Test
+        run: go test

go.mod

@@ -1,5 +1,5 @@
 module github.com/t2bot/go-singleflight-streams
 
-go 1.19
+go 1.20
 
-require golang.org/x/sync v0.2.0
+require golang.org/x/sync v0.3.0

go.sum

@@ -1,2 +1,2 @@
-golang.org/x/sync v0.2.0 h1:PUR+T4wwASmuSTYdKjYHI5TD22Wy5ogLU5qZCOLxBrI=
-golang.org/x/sync v0.2.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
+golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=

sfstreams.go

@@ -1,7 +1,6 @@
 package sfstreams
 
 import (
-	"errors"
 	"fmt"
 	"io"
 	"sync"
@@ -39,7 +38,7 @@ func (g *Group) Do(key string, fn func() (io.ReadCloser, error)) (reader io.Read
 	if _, ok := g.calls[key]; !ok {
 		g.calls[key] = make([]chan<- io.ReadCloser, 0)
 	}
-	resCh := make(chan io.ReadCloser)
+	resCh := make(chan io.ReadCloser, 1)
 	defer close(resCh)
 	g.calls[key] = append(g.calls[key], resCh)
 
@@ -54,7 +53,7 @@ func (g *Group) Do(key string, fn func() (io.ReadCloser, error)) (reader io.Read
 //
 // The returned channel is not closed.
 func (g *Group) DoChan(key string, fn func() (io.ReadCloser, error)) <-chan ReaderResult {
-	ch := make(chan ReaderResult)
+	ch := make(chan ReaderResult, 1)
 	go func(ch chan ReaderResult, g *Group) {
 		r, err, shared := g.Do(key, fn)
 		ch <- ReaderResult{
@@ -87,7 +86,7 @@ func (g *Group) doWork(key string, fn func() (io.ReadCloser, error)) func() (int
 		defer g.mu.Unlock()
 		g.sf.Forget(key) // we won't be processing future calls, so wrap it up
 		if chans, ok := g.calls[key]; !ok {
-			return nil, errors.New(fmt.Sprintf("expected to find singleflight key \"%s\", but didn't", key))
+			return nil, fmt.Errorf("expected to find singleflight key \"%s\", but didn't", key)
 		} else {
 			skipStream := fnRes == nil
 			writers := make([]io.Writer, 0) // they're actually PipeWriters, but the MultiWriter doesn't like that...
@@ -121,8 +120,9 @@ func (g *Group) doWork(key string, fn func() (io.ReadCloser, error)) func() (int
 }
 
 func finishCopy(writers []io.Writer, fnRes io.ReadCloser) {
-	//goland:noinspection GoUnhandledErrorResult
-	defer fnRes.Close()
+	defer func(fnRes io.ReadCloser) {
+		_ = fnRes.Close()
+	}(fnRes)
 	mw := io.MultiWriter(writers...)
 	_, copyErr := io.Copy(mw, fnRes)
 	for _, w := range writers {