Fix lint warnings

This commit fixes most of warnings, but not all of them.

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

.golangci.yml

@@ -1,6 +1,7 @@
 linters-settings:
   govet:
-    check-shadowing: true
+    # Using err repeatedly considered as shadowing.
+    check-shadowing: false
   golint:
     min-confidence: 0
   gocyclo:

bytestream.go

@@ -58,6 +58,7 @@ func ByteStreamConsumer(opts ...byteStreamOpt) Consumer {
 				close = cl.Close
 			}
 		}
+		//nolint:errcheck // closing a reader wouldn't fail.
 		defer close()
 
 		if wrtr, ok := data.(io.Writer); ok {
@@ -114,6 +115,7 @@ func ByteStreamProducer(opts ...byteStreamOpt) Producer {
 				close = cl.Close
 			}
 		}
+		//nolint:errcheck // TODO: closing a writer would fail.
 		defer close()
 
 		if rc, ok := data.(io.ReadCloser); ok {

client/keepalive.go

@@ -46,7 +46,10 @@ func (d *drainingReadCloser) Read(p []byte) (n int, err error) {
 func (d *drainingReadCloser) Close() error {
 	// drain buffer
 	if atomic.LoadUint32(&d.seenEOF) != 1 {
-		//#nosec
+		// If the reader side (a HTTP server) is misbehaving, it still may send
+		// some bytes, but the closer ignores them to keep the underling
+		// connection open.
+		//nolint:errcheck
 		io.Copy(ioutil.Discard, d.rdr)
 	}
 	return d.rdr.Close()

client/request.go

@@ -93,6 +93,15 @@ func (r *request) BuildHTTP(mediaType, basePath string, producers map[string]run
 func escapeQuotes(s string) string {
 	return strings.NewReplacer("\\", "\\\\", `"`, "\\\"").Replace(s)
 }
+
+func logClose(err error, pw *io.PipeWriter) {
+	log.Println(err)
+	closeErr := pw.CloseWithError(err)
+	if closeErr != nil {
+		log.Println(closeErr)
+	}
+}
+
 func (r *request) buildHTTP(mediaType, basePath string, producers map[string]runtime.Producer, registry strfmt.Registry, auth runtime.ClientAuthInfoWriter) (*http.Request, error) {
 	// build the data
 	if err := r.writer.WriteToRequest(r, registry); err != nil {
@@ -137,8 +146,7 @@ func (r *request) buildHTTP(mediaType, basePath string, producers map[string]run
 			for fn, v := range r.formFields {
 				for _, vi := range v {
 					if err := mp.WriteField(fn, vi); err != nil {
-						pw.CloseWithError(err)
-						log.Println(err)
+						logClose(err, pw)
 						return
 					}
 				}
@@ -157,8 +165,7 @@ func (r *request) buildHTTP(mediaType, basePath string, producers map[string]run
 					buf := make([]byte, 512)
 					size, err := fi.Read(buf)
 					if err != nil {
-						_ = pw.CloseWithError(err)
-						log.Println(err)
+						logClose(err, pw)
 						return
 					}
 					fileContentType := http.DetectContentType(buf)
@@ -173,13 +180,11 @@ func (r *request) buildHTTP(mediaType, basePath string, producers map[string]run
 
 					wrtr, err := mp.CreatePart(h)
 					if err != nil {
-						pw.CloseWithError(err)
-						log.Println(err)
+						logClose(err, pw)
 						return
 					}
 					if _, err := io.Copy(wrtr, newFi); err != nil {
-						pw.CloseWithError(err)
-						log.Println(err)
+						logClose(err, pw)
 					}
 				}
 			}

request.go

@@ -48,7 +48,7 @@ func HasBody(r *http.Request) bool {
 		return true
 	}
 
-	if r.Header.Get(http.CanonicalHeaderKey("content-length")) != "" {
+	if r.Header.Get("content-length") != "" {
 		// in this case, no Transfer-Encoding should be present
 		// we have a header set but it was explicitly set to 0, so we assume no body
 		return false

text.go

@@ -41,7 +41,6 @@ func TextConsumer() Consumer {
 
 		// If the buffer is empty, no need to unmarshal it, which causes a panic.
 		if len(b) == 0 {
-			data = ""
 			return nil
 		}