Several cs fixes (#9420)

- Fix grpcurl example in the README to reflect now-required replacement
strategy arg
- Make incremental update computation properly return an error when no
changes found
- Don't crash the CS CLI when failing to add a document
- Expose the GitClient from github.go, it will be used by the BB CLI in
a change shortly

Author: jdelfino

codesearch/README.md

@@ -68,7 +68,7 @@ Some example queries:
   $ grpc_cli call --metadata x-buildbuddy-api-key:YOUR_DEV_API_KEY localhost:2633 codesearch.service.CodesearchService.Index 'git_repo:<repo_url:"https://github.com/buildbuddy-io/buildbuddy"> repo_state:<commit_sha:"master">'
   #
   # grpcurl version:
-  $ grpcurl -plaintext -H "x-buildbuddy-api-key:YOUR_DEV_API_KEY" -d '{"git_repo": {"repo_url":"https://github.com/buildbuddy-io/buildbuddy"}, "repo_state": {"commit_sha":"master"}}' localhost:2633 codesearch.service.CodesearchService.Index
+  $ grpcurl -plaintext -H "x-buildbuddy-api-key:YOUR_DEV_API_KEY" -d '{"git_repo": {"repo_url":"https://github.com/buildbuddy-io/buildbuddy"}, "repo_state": {"commit_sha":"master"}, "replacement_strategy": 1}' localhost:2633 codesearch.service.CodesearchService.Index
 ```
 
 ## Perform a Search (server)

codesearch/cmd/cli/cli.go

@@ -181,7 +181,7 @@ func handleIndex(args []string) {
 				}
 
 				if err := github.AddFileToIndex(iw, repoURL, commitSHA, path, buf); err != nil {
-					log.Fatalf("failed to add file %s: %s", path, err)
+					log.Infof("Skipping file %s: %s", path, err)
 				}
 			}
 			return nil

codesearch/github/github.go

@@ -182,8 +182,7 @@ func validateFile(content []byte) error {
 	return nil
 }
 
-// This type exists to enable dependency injection for testing.
-type gitClient interface {
+type GitClient interface {
 	ExecuteCommand(args ...string) (string, error)
 	LoadFileContents(fileToLoad string) ([]byte, error)
 }
@@ -192,7 +191,7 @@ type commandLineGitClient struct {
 	repoDir string
 }
 
-func NewCommandLineGitClient(repoDir string) gitClient {
+func NewCommandLineGitClient(repoDir string) GitClient {
 	return &commandLineGitClient{repoDir: repoDir}
 }
 
@@ -215,7 +214,7 @@ func (c *commandLineGitClient) LoadFileContents(filename string) ([]byte, error)
 	return content, nil
 }
 
-func processDiffTreeLine(gc gitClient, line string, commit *inpb.Commit) error {
+func processDiffTreeLine(gc GitClient, line string, commit *inpb.Commit) error {
 	// diff-tree lines are in the format "<src mode> <dst mode> <src sha> <dst sha> <status>\t<src path>\t<dst path(copy/rename only)>""
 	// Documentation: https://git-scm.com/docs/git-diff-tree
 	parts := strings.Split(line, " ")
@@ -275,7 +274,7 @@ func processDiffTreeLine(gc gitClient, line string, commit *inpb.Commit) error {
 // The information is extracted using the git command line client on a local clone of a repo.
 // The payload contains a list of commits, the file contents for each added/modified file, and a list
 // of deleted filenames.
-func ComputeIncrementalUpdate(gc gitClient, firstSha, lastSha string) (*inpb.IncrementalUpdate, error) {
+func ComputeIncrementalUpdate(gc GitClient, firstSha, lastSha string) (*inpb.IncrementalUpdate, error) {
 	commitRange := fmt.Sprintf("%s..%s", firstSha, lastSha)
 
 	changesStr, err := gc.ExecuteCommand("whatchanged", "--first-parent", "--format=%H", "--reverse", commitRange)
@@ -287,7 +286,7 @@ func ComputeIncrementalUpdate(gc gitClient, firstSha, lastSha string) (*inpb.Inc
 	if len(changes) > maxAllowedChanges {
 		return nil, fmt.Errorf("too many changes in commit range %s..%s: %d", firstSha, lastSha, len(changes))
 	}
-	if len(changes) == 0 {
+	if len(changes) == 0 || (len(changes) == 1 && len(changes[0]) == 0) {
 		return nil, fmt.Errorf("no commits found between %s and %s", firstSha, lastSha)
 	}
 

codesearch/github/github_test.go

@@ -519,3 +519,20 @@ def456
 		},
 	}, result)
 }
+
+func TestComputeIncrementalUpdate_NoChanges(t *testing.T) {
+	firstSHA := "abc123"
+	lastSHA := "def456"
+
+	fakeClient := &fakeGitClient{
+		t: t,
+		commands: map[string]string{
+			fmt.Sprintf("whatchanged --first-parent --format=%%H --reverse %s..%s", firstSHA, lastSHA): "\n",
+		},
+		files: map[string][]byte{},
+	}
+
+	result, err := ComputeIncrementalUpdate(fakeClient, firstSHA, lastSHA)
+	assert.Error(t, err)
+	assert.Nil(t, result)
+}

codesearch/server/server.go

@@ -327,7 +327,7 @@ func (css *codesearchServer) Index(ctx context.Context, req *inpb.IndexRequest)
 		unlockFn := css.repoLocks.Lock(lockKey)
 		defer unlockFn()
 
-		log.Infof("Starting indexing %q@%s", repoURL, commitSHA)
+		log.Infof("Starting indexing %s@%s", repoURL, commitSHA)
 
 		var err error
 		switch req.GetReplacementStrategy() {