vet: add check for trailing spaces (#7576)

* vet: trailing spaces check

Author: purnesh42H

CONTRIBUTING.md

@@ -25,8 +25,8 @@ How to get your contributions merged smoothly and quickly.
   is a great place to start. These issues are well-documented and usually can be
   resolved with a single pull request.
 
-- If you are adding a new file, make sure it has the copyright message template 
-  at the top as a comment. You can copy over the message from an existing file 
+- If you are adding a new file, make sure it has the copyright message template
+  at the top as a comment. You can copy over the message from an existing file
   and update the year.
 
 - The grpc package should only depend on standard Go packages and a small number
@@ -41,10 +41,10 @@ How to get your contributions merged smoothly and quickly.
 - Provide a good **PR description** as a record of **what** change is being made
   and **why** it was made. Link to a github issue if it exists.
 
-- If you want to fix formatting or style, consider whether your changes are an 
-  obvious improvement or might be considered a personal preference. If a style 
-  change is based on preference, it likely will not be accepted. If it corrects 
-  widely agreed-upon anti-patterns, then please do create a PR and explain the 
+- If you want to fix formatting or style, consider whether your changes are an
+  obvious improvement or might be considered a personal preference. If a style
+  change is based on preference, it likely will not be accepted. If it corrects
+  widely agreed-upon anti-patterns, then please do create a PR and explain the
   benefits of the change.
 
 - Unless your PR is trivial, you should expect there will be reviewer comments

Documentation/server-reflection-tutorial.md

@@ -103,7 +103,7 @@ The `list` command lists services exposed at a given port:
 - Describe all services
 
   The `describe` command inspects a service given its full name (in the format
-  of \<package\>.\<service\>). 
+  of \<package\>.\<service\>).
 
   ```sh
   $ grpcurl -plaintext localhost:50051 describe helloworld.Greeter

authz/grpc_authz_end2end_test.go

@@ -78,7 +78,7 @@ var authzTests = map[string]struct {
 	"DeniesRPCMatchInDenyNoMatchInAllow": {
 		authzPolicy: `{
 				"name": "authz",
-				"allow_rules": 
+				"allow_rules":
 				[
 					{
 						"name": "allow_StreamingOutputCall",
@@ -166,11 +166,11 @@ var authzTests = map[string]struct {
 								"/grpc.testing.TestService/UnaryCall",
 								"/grpc.testing.TestService/StreamingInputCall"
 							],
-							"headers": 
+							"headers":
 							[
 								{
 									"key": "key-abc",
-									"values": 
+									"values":
 									[
 										"val-abc",
 										"val-def"
@@ -250,7 +250,7 @@ var authzTests = map[string]struct {
 				[
 					{
 						"name": "allow_StreamingOutputCall",
-						"request": 
+						"request":
 						{
 							"paths":
 							[

authz/grpc_authz_server_interceptors_test.go

@@ -57,9 +57,9 @@ func (s) TestNewStatic(t *testing.T) {
 			wantErr:     fmt.Errorf(`"name" is not present`),
 		},
 		"ValidPolicyCreatesInterceptor": {
-			authzPolicy: `{		
+			authzPolicy: `{
 				"name": "authz",
-				"allow_rules": 
+				"allow_rules":
 				[
 					{
 						"name": "allow_all"

cmd/protoc-gen-go-grpc/protoc-gen-go-grpc_test.sh

@@ -15,7 +15,7 @@
 # limitations under the License.
 
 # Uncomment to enable debugging.
-# set -x 
+# set -x
 
 WORKDIR="$(dirname $0)"
 TEMPDIR=$(mktemp -d)
@@ -24,7 +24,7 @@ trap "rm -rf ${TEMPDIR}" EXIT
 
 # Build protoc-gen-go-grpc binary and add to $PATH.
 pushd "${WORKDIR}"
-go build -o "${TEMPDIR}" . 
+go build -o "${TEMPDIR}" .
 PATH="${TEMPDIR}:${PATH}"
 popd
 
@@ -38,7 +38,7 @@ GENFILE="${TEMPDIR}/examples/route_guide/routeguide/route_guide_grpc.pb.go"
 
 # diff is piped to [[ $? == 1 ]] to avoid exiting on diff but exit on error
 # (like if the file was not found). See man diff for more info.
-DIFF=$(diff "${GOLDENFILE}" "${GENFILE}" || [[ $? == 1 ]]) 
+DIFF=$(diff "${GOLDENFILE}" "${GENFILE}" || [[ $? == 1 ]])
 if [[ -n "${DIFF}" ]]; then
     echo -e "ERROR: Generated file differs from golden file:\n${DIFF}"
     echo -e "If you have made recent changes to protoc-gen-go-grpc," \

examples/features/advancedtls/README.md

@@ -16,7 +16,7 @@ The clients are designed to call these servers with varying configurations of cr
 ```
 # Run the server
 $ go run server/main.go -credentials_directory $(pwd)/creds
-# Run the clients from the `grpc-go/examples/features/advancedtls` directory 
+# Run the clients from the `grpc-go/examples/features/advancedtls` directory
 $ go run client/main.go -credentials_directory $(pwd)/creds
 ```
 

examples/features/advancedtls/creds/client_cert.pem

@@ -49,15 +49,15 @@ Certificate:
                     6e:bb:bb
                 Exponent: 65537 (0x10001)
         X509v3 extensions:
-            X509v3 Subject Key Identifier: 
+            X509v3 Subject Key Identifier:
                 DE:03:BD:A3:0E:63:F4:97:C2:52:70:63:E8:BE:A9:DF:F1:9A:7B:56
-            X509v3 Authority Key Identifier: 
+            X509v3 Authority Key Identifier:
                 50:76:C3:5C:6B:12:E1:92:0F:28:F8:F2:43:A6:80:C2:9C:E8:56:D6
-            X509v3 Basic Constraints: 
+            X509v3 Basic Constraints:
                 CA:FALSE
-            X509v3 Key Usage: 
+            X509v3 Key Usage:
                 Digital Signature, Key Encipherment
-            X509v3 Subject Alternative Name: 
+            X509v3 Subject Alternative Name:
                 DNS:localhost, IP Address:0.0.0.0
     Signature Algorithm: sha256WithRSAEncryption
     Signature Value:

examples/features/advancedtls/creds/client_cert_revoked.pem

@@ -49,15 +49,15 @@ Certificate:
                     6e:bb:bb
                 Exponent: 65537 (0x10001)
         X509v3 extensions:
-            X509v3 Subject Key Identifier: 
+            X509v3 Subject Key Identifier:
                 DE:03:BD:A3:0E:63:F4:97:C2:52:70:63:E8:BE:A9:DF:F1:9A:7B:56
-            X509v3 Authority Key Identifier: 
+            X509v3 Authority Key Identifier:
                 50:76:C3:5C:6B:12:E1:92:0F:28:F8:F2:43:A6:80:C2:9C:E8:56:D6
-            X509v3 Basic Constraints: 
+            X509v3 Basic Constraints:
                 CA:FALSE
-            X509v3 Key Usage: 
+            X509v3 Key Usage:
                 Digital Signature, Key Encipherment
-            X509v3 Subject Alternative Name: 
+            X509v3 Subject Alternative Name:
                 DNS:localhost, IP Address:0.0.0.0
     Signature Algorithm: sha256WithRSAEncryption
     Signature Value:

examples/features/advancedtls/creds/server_cert.pem

@@ -49,15 +49,15 @@ Certificate:
                     03:71:c1
                 Exponent: 65537 (0x10001)
         X509v3 extensions:
-            X509v3 Subject Key Identifier: 
+            X509v3 Subject Key Identifier:
                 4C:57:E2:72:97:CF:DC:C4:B8:4E:DB:D4:C1:C6:3D:AE:EF:D7:0A:19
-            X509v3 Authority Key Identifier: 
+            X509v3 Authority Key Identifier:
                 50:76:C3:5C:6B:12:E1:92:0F:28:F8:F2:43:A6:80:C2:9C:E8:56:D6
-            X509v3 Basic Constraints: 
+            X509v3 Basic Constraints:
                 CA:FALSE
-            X509v3 Key Usage: 
+            X509v3 Key Usage:
                 Digital Signature, Key Encipherment
-            X509v3 Subject Alternative Name: 
+            X509v3 Subject Alternative Name:
                 DNS:localhost, IP Address:0.0.0.0
     Signature Algorithm: sha256WithRSAEncryption
     Signature Value:

examples/features/advancedtls/creds/server_cert_revoked.pem

@@ -49,15 +49,15 @@ Certificate:
                     03:71:c1
                 Exponent: 65537 (0x10001)
         X509v3 extensions:
-            X509v3 Subject Key Identifier: 
+            X509v3 Subject Key Identifier:
                 4C:57:E2:72:97:CF:DC:C4:B8:4E:DB:D4:C1:C6:3D:AE:EF:D7:0A:19
-            X509v3 Authority Key Identifier: 
+            X509v3 Authority Key Identifier:
                 50:76:C3:5C:6B:12:E1:92:0F:28:F8:F2:43:A6:80:C2:9C:E8:56:D6
-            X509v3 Basic Constraints: 
+            X509v3 Basic Constraints:
                 CA:FALSE
-            X509v3 Key Usage: 
+            X509v3 Key Usage:
                 Digital Signature, Key Encipherment
-            X509v3 Subject Alternative Name: 
+            X509v3 Subject Alternative Name:
                 DNS:localhost, IP Address:0.0.0.0
     Signature Algorithm: sha256WithRSAEncryption
     Signature Value:

examples/features/debugging/README.md

@@ -3,12 +3,12 @@
 Currently, grpc provides two major tools to help user debug issues, which are logging and channelz.
 
 ## Logs
-gRPC has put substantial logging instruments on critical paths of gRPC to help users debug issues. 
+gRPC has put substantial logging instruments on critical paths of gRPC to help users debug issues.
 The [Log Levels](https://github.com/grpc/grpc-go/blob/master/Documentation/log_levels.md) doc describes
 what each log level means in the gRPC context.
 
-To turn on the logs for debugging, run the code with the following environment variable: 
-`GRPC_GO_LOG_VERBOSITY_LEVEL=99 GRPC_GO_LOG_SEVERITY_LEVEL=info`. 
+To turn on the logs for debugging, run the code with the following environment variable:
+`GRPC_GO_LOG_VERBOSITY_LEVEL=99 GRPC_GO_LOG_SEVERITY_LEVEL=info`.
 
 ## Channelz
 We also provide a runtime debugging tool, Channelz, to help users with live debugging.
@@ -17,7 +17,7 @@ See the channelz blog post here ([link](https://grpc.io/blog/a-short-introductio
 details about how to use channelz service to debug live program.
 
 ## Try it
-The example is able to showcase how logging and channelz can help with debugging. See the channelz 
+The example is able to showcase how logging and channelz can help with debugging. See the channelz
 blog post linked above for full explanation.
 
 ```

examples/features/encryption/README.md

@@ -29,9 +29,9 @@ create grpc
 base on TLS. Refer to the
 [godoc](https://godoc.org/google.golang.org/grpc/credentials) for details.
 
-In our example, we use the public/private keys created ahead: 
-* "server_cert.pem" contains the server certificate (public key). 
-* "server_key.pem" contains the server private key. 
+In our example, we use the public/private keys created ahead:
+* "server_cert.pem" contains the server certificate (public key).
+* "server_key.pem" contains the server private key.
 * "ca_cert.pem" contains the certificate (certificate authority)
 that can verify the server's certificate.
 
@@ -56,7 +56,7 @@ And finally we make an RPC call over the created `grpc.ClientConn` to test the s
 connection based upon TLS is successfully up.
 
 ### ALTS
-NOTE: ALTS currently needs special early access permission on GCP. You can ask 
+NOTE: ALTS currently needs special early access permission on GCP. You can ask
 about the detailed process in https://groups.google.com/forum/#!forum/grpc-io.
 
 ALTS is the Google's Application Layer Transport Security, which supports mutual
@@ -93,12 +93,12 @@ allows users to configure mutual TLS at the connection level.
 
 In this example, we use the following public/private keys created ahead of time:
 
-* "server_cert.pem" contains the server's certificate (public key). 
-* "server_key.pem" contains the server's private key. 
+* "server_cert.pem" contains the server's certificate (public key).
+* "server_key.pem" contains the server's private key.
 * "ca_cert.pem" contains the certificate of the certificate authority that can
   verify the server's certificate.
-* "client_cert.pem" contains the client's certificate (public key). 
-* "client_key.pem" contains the client's private key. 
+* "client_cert.pem" contains the client's certificate (public key).
+* "client_key.pem" contains the client's private key.
 * "client_ca_cert.pem" contains the certificate of the certificate authority
   that can verify the client's certificate.
 

examples/features/health/README.md

@@ -3,7 +3,7 @@
 gRPC provides a health library to communicate a system's health to their clients.
 It works by providing a service definition via the [health/v1](https://github.com/grpc/grpc-proto/blob/master/grpc/health/v1/health.proto) api.
 
-By using the health library, clients can gracefully avoid using servers as they encounter issues. 
+By using the health library, clients can gracefully avoid using servers as they encounter issues.
 Most languages provide an implementation out of box, making it interoperable between systems.
 
 ## Try it
@@ -30,7 +30,7 @@ This configuration indicates which backend `serviceName` should be inspected whe
 An empty string (`""`) typically indicates the overall health of a server should be reported.
 
 ```go
-// import grpc/health to enable transparent client side checking 
+// import grpc/health to enable transparent client side checking
 import _ "google.golang.org/grpc/health"
 
 // set up appropriate service config
@@ -59,6 +59,6 @@ This state is often seen at the start up of a server instance.
 Conversely, `NOT_SERVING` indicates the system is unable to service requests at the time.
 
 `SERVICE_UNKNOWN` communicates the `serviceName` requested by the client is not known by the server.
-This status is only reported by the `Watch()` call. 
+This status is only reported by the `Watch()` call.
 
 A server may toggle its health using `healthServer.SetServingStatus("serviceName", servingStatus)`.

examples/features/metadata_interceptor/README.md

@@ -57,7 +57,7 @@ func (s *wrappedStream) Context() context.Context {
 }
 
 func SomeStreamInterceptor(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
-    // Get the incoming metadata from the RPC context, and add a new 
+    // Get the incoming metadata from the RPC context, and add a new
     // key-value pair to it.
     md, ok := metadata.FromIncomingContext(ctx)
     md.Append("key1", "value1")

examples/features/stats_monitoring/README.md

@@ -1,8 +1,8 @@
 # Stats Monitoring Handler
 
-This example demonstrates the use of the [`stats`](https://pkg.go.dev/google.golang.org/grpc/stats) package for reporting various  
-network and RPC stats.  
-_Note that all fields are READ-ONLY and the APIs of the `stats` package are  
+This example demonstrates the use of the [`stats`](https://pkg.go.dev/google.golang.org/grpc/stats) package for reporting various
+network and RPC stats.
+_Note that all fields are READ-ONLY and the APIs of the `stats` package are
 experimental_.
 
 ## Try it
@@ -17,42 +17,42 @@ go run client/main.go
 
 ## Explanation
 
-gRPC provides a mechanism to hook on to various events (phases) of the  
-request-response network cycle through the [`stats.Handler`](https://pkg.go.dev/google.golang.org/grpc/stats#Handler) interface. To access  
-these events, a concrete type that implements `stats.Handler` should be passed to  
-`grpc.WithStatsHandler()` on the client side and `grpc.StatsHandler()` on the  
+gRPC provides a mechanism to hook on to various events (phases) of the
+request-response network cycle through the [`stats.Handler`](https://pkg.go.dev/google.golang.org/grpc/stats#Handler) interface. To access
+these events, a concrete type that implements `stats.Handler` should be passed to
+`grpc.WithStatsHandler()` on the client side and `grpc.StatsHandler()` on the
 server side.
 
-The `HandleRPC(context.Context, RPCStats)` method on `stats.Handler` is called  
-multiple times during a request-response cycle, and various event stats are  
-passed to its `RPCStats` parameter (an interface). The concrete types that  
-implement this interface are: `*stats.Begin`, `*stats.InHeader`, `*stats.InPayload`,  
-`*stats.InTrailer`, `*stats.OutHeader`, `*stats.OutPayload`, `*stats.OutTrailer`, and  
+The `HandleRPC(context.Context, RPCStats)` method on `stats.Handler` is called
+multiple times during a request-response cycle, and various event stats are
+passed to its `RPCStats` parameter (an interface). The concrete types that
+implement this interface are: `*stats.Begin`, `*stats.InHeader`, `*stats.InPayload`,
+`*stats.InTrailer`, `*stats.OutHeader`, `*stats.OutPayload`, `*stats.OutTrailer`, and
 `*stats.End`. The order of these events differs on client and server.
 
-Similarly, the `HandleConn(context.Context, ConnStats)` method on `stats.Handler`  
-is called twice, once at the beginning of the connection with `*stats.ConnBegin`  
+Similarly, the `HandleConn(context.Context, ConnStats)` method on `stats.Handler`
+is called twice, once at the beginning of the connection with `*stats.ConnBegin`
 and once at the end with `*stats.ConnEnd`.
 
-The [`stats.Handler`](https://pkg.go.dev/google.golang.org/grpc/stats#Handler) interface also provides  
-`TagRPC(context.Context, *RPCTagInfo) context.Context` and  
-`TagConn(context.Context, *ConnTagInfo) context.Context` methods. These methods  
+The [`stats.Handler`](https://pkg.go.dev/google.golang.org/grpc/stats#Handler) interface also provides
+`TagRPC(context.Context, *RPCTagInfo) context.Context` and
+`TagConn(context.Context, *ConnTagInfo) context.Context` methods. These methods
 are mainly used to attach network related information to the given context.
 
-The `TagRPC(context.Context, *RPCTagInfo) context.Context` method returns a  
-context from which the context used for the rest lifetime of the RPC will be  
+The `TagRPC(context.Context, *RPCTagInfo) context.Context` method returns a
+context from which the context used for the rest lifetime of the RPC will be
 derived. This behavior is consistent between the gRPC client and server.
 
-The context returned from  
+The context returned from
 `TagConn(context.Context, *ConnTagInfo) context.Context` has varied lifespan:
 
-- In the gRPC client:  
-  The context used for the rest lifetime of the RPC will NOT be derived from  
-  this context. Hence the information attached to this context can only be  
+- In the gRPC client:
+  The context used for the rest lifetime of the RPC will NOT be derived from
+  this context. Hence the information attached to this context can only be
   consumed by `HandleConn(context.Context, ConnStats)` method.
-- In the gRPC server:  
-  The context used for the rest lifetime of the RPC will be derived from  
+- In the gRPC server:
+  The context used for the rest lifetime of the RPC will be derived from
   this context.
 
-NOTE: The [stats](https://pkg.go.dev/google.golang.org/grpc/stats) package should only be used for network monitoring purposes,  
+NOTE: The [stats](https://pkg.go.dev/google.golang.org/grpc/stats) package should only be used for network monitoring purposes,
 and not as an alternative to [interceptors](https://github.com/grpc/grpc-go/blob/master/examples/features/interceptor).

scripts/vet.sh

@@ -67,6 +67,9 @@ not git grep "\"github.com/golang/protobuf/*" -- "*.go" ':(exclude)reflection/te
 # - Ensure all usages of grpc_testing package are renamed when importing.
 not git grep "\(import \|^\s*\)\"google.golang.org/grpc/interop/grpc_testing" -- "*.go"
 
+# - Ensure that no trailing spaces are found.
+not git grep '[[:blank:]]$'
+
 # - Ensure all xds proto imports are renamed to *pb or *grpc.
 git grep '"github.com/envoyproxy/go-control-plane/envoy' -- '*.go' ':(exclude)*.pb.go' | not grep -v 'pb "\|grpc "'