Enable streaming blame by default (#58582)

This has been implemented and run for a while on Sourcegraph.com. I think we should open it for all users, or remove the code for it.
Since it fixes performance issues, I would want to err on keeping and on for all.

client/web/src/featureFlags/featureFlags.ts

@@ -12,7 +12,6 @@ export const FEATURE_FLAGS = [
     'admin-analytics-cache-disabled',
     'search-input-show-history',
     'search-results-keyboard-navigation',
-    'enable-streaming-git-blame',
     'plg-enable-add-codehost-widget',
     'accessible-file-tree',
     'accessible-symbol-tree',

client/web/src/repo/blame/useBlameHunks.ts

@@ -12,14 +12,7 @@ import { makeRepoURI } from '@sourcegraph/shared/src/util/url'
 import { useObservable } from '@sourcegraph/wildcard'
 
 import { requestGraphQL } from '../../backend/graphql'
-import { useFeatureFlag } from '../../featureFlags/useFeatureFlag'
-import type {
-    ExternalServiceKind,
-    FirstCommitDateResult,
-    FirstCommitDateVariables,
-    GitBlameResult,
-    GitBlameVariables,
-} from '../../graphql-operations'
+import type { ExternalServiceKind, FirstCommitDateResult, FirstCommitDateVariables } from '../../graphql-operations'
 
 import { useBlameVisibility } from './useBlameVisibility'
 
@@ -69,84 +62,6 @@ export interface BlameHunkData {
     firstCommitDate: Date | undefined
 }
 
-const fetchBlameViaGraphQL = memoizeObservable(
-    ({
-        repoName,
-        revision,
-        filePath,
-        sourcegraphURL,
-    }: {
-        repoName: string
-        revision: string
-        filePath: string
-        sourcegraphURL: string
-    }): Observable<BlameHunkData> =>
-        requestGraphQL<GitBlameResult, GitBlameVariables>(
-            gql`
-                query GitBlame($repo: String!, $rev: String!, $path: String!) {
-                    repository(name: $repo) {
-                        externalURLs {
-                            url
-                            serviceKind
-                        }
-                        firstEverCommit {
-                            author {
-                                date
-                            }
-                        }
-                        commit(rev: $rev) {
-                            blob(path: $path) {
-                                blame(startLine: 0, endLine: 0) {
-                                    startLine
-                                    endLine
-                                    author {
-                                        person {
-                                            email
-                                            displayName
-                                            avatarURL
-                                            user {
-                                                username
-                                                displayName
-                                                avatarURL
-                                            }
-                                        }
-                                        date
-                                    }
-                                    message
-                                    rev
-                                    commit {
-                                        url
-                                        parents {
-                                            oid
-                                        }
-                                    }
-                                }
-                            }
-                        }
-                    }
-                }
-            `,
-            { repo: repoName, rev: revision, path: filePath }
-        ).pipe(
-            map(dataOrThrowErrors),
-            map(({ repository }) => {
-                const hunks = repository?.commit?.blob?.blame
-                const firstCommitDate = repository?.firstEverCommit?.author?.date
-                const externalURLs = repository?.externalURLs
-                if (hunks) {
-                    return {
-                        current: hunks.map(blame => addDisplayInfoForHunk(blame, sourcegraphURL)),
-                        externalURLs,
-                        firstCommitDate: firstCommitDate ? new Date(firstCommitDate) : undefined,
-                    }
-                }
-
-                return { current: undefined, externalURLs: undefined, firstCommitDate: undefined }
-            })
-        ),
-    makeRepoURI
-)
-
 interface RawStreamHunk {
     author: {
         Name: string
@@ -176,9 +91,6 @@ interface RawStreamHunk {
  * To reduce the backend pressure and improve the experience, this fetch
  * implementation uses a SSE stream to load the blame hunks in chunks.
  *
- * It is controlled via the `enable-streaming-git-blame` feature flag and is
- * currently not enabled by default.
- *
  * Since we also need the first commit date for the blame recency calculations,
  * this implementation uses Promise.all() to load both data sources in parallel.
  */
@@ -347,8 +259,6 @@ export const useBlameHunks = (
     },
     sourcegraphURL: string
 ): BlameHunkData => {
-    const [enableStreamingGitBlame, status] = useFeatureFlag('enable-streaming-git-blame')
-
     const [isBlameVisible] = useBlameVisibility(isPackage)
     const shouldFetchBlame = isBlameVisible && status !== 'initial'
 
@@ -356,11 +266,9 @@ export const useBlameHunks = (
         useMemo(
             () =>
                 shouldFetchBlame
-                    ? enableStreamingGitBlame
-                        ? fetchBlameViaStreaming({ revision, repoName, filePath, sourcegraphURL })
-                        : fetchBlameViaGraphQL({ revision, repoName, filePath, sourcegraphURL })
+                    ? fetchBlameViaStreaming({ revision, repoName, filePath, sourcegraphURL })
                     : of({ current: undefined, externalURLs: undefined, firstCommitDate: undefined }),
-            [shouldFetchBlame, enableStreamingGitBlame, revision, repoName, filePath, sourcegraphURL]
+            [shouldFetchBlame, revision, repoName, filePath, sourcegraphURL]
         )
     )
 

cmd/frontend/internal/httpapi/BUILD.bazel

@@ -44,7 +44,6 @@ go_library(
         "//internal/encryption/keyring",
         "//internal/env",
         "//internal/errcode",
-        "//internal/featureflag",
         "//internal/gitserver",
         "//internal/gitserver/gitdomain",
         "//internal/httpcli",
@@ -107,7 +106,6 @@ go_test(
         "//internal/database",
         "//internal/database/dbmocks",
         "//internal/errcode",
-        "//internal/featureflag",
         "//internal/gitserver",
         "//internal/gitserver/gitdomain",
         "//internal/httpcli",

cmd/frontend/internal/httpapi/stream_blame.go

@@ -16,7 +16,6 @@ import (
 	"github.com/sourcegraph/sourcegraph/internal/api"
 	"github.com/sourcegraph/sourcegraph/internal/database"
 	"github.com/sourcegraph/sourcegraph/internal/errcode"
-	"github.com/sourcegraph/sourcegraph/internal/featureflag"
 	"github.com/sourcegraph/sourcegraph/internal/gitserver"
 	"github.com/sourcegraph/sourcegraph/internal/gitserver/gitdomain"
 	streamhttp "github.com/sourcegraph/sourcegraph/internal/search/streaming/http"
@@ -30,11 +29,6 @@ import (
 // before that.
 func handleStreamBlame(logger log.Logger, db database.DB, gitserverClient gitserver.Client) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		flags := featureflag.FromContext(r.Context())
-		if !flags.GetBoolOr("enable-streaming-git-blame", false) {
-			w.WriteHeader(404)
-			return
-		}
 		tr, ctx := trace.New(r.Context(), "blame.Stream")
 		defer tr.End()
 		r = r.WithContext(ctx)

cmd/frontend/internal/httpapi/stream_blame_test.go

@@ -9,18 +9,18 @@ import (
 
 	"github.com/gorilla/mux"
 	"github.com/sourcegraph/log/logtest"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
 	"github.com/sourcegraph/sourcegraph/cmd/frontend/backend"
 	"github.com/sourcegraph/sourcegraph/internal/api"
 	"github.com/sourcegraph/sourcegraph/internal/database"
 	"github.com/sourcegraph/sourcegraph/internal/database/dbmocks"
 	"github.com/sourcegraph/sourcegraph/internal/errcode"
-	"github.com/sourcegraph/sourcegraph/internal/featureflag"
 	"github.com/sourcegraph/sourcegraph/internal/gitserver"
 	"github.com/sourcegraph/sourcegraph/internal/gitserver/gitdomain"
 	"github.com/sourcegraph/sourcegraph/internal/types"
 	"github.com/sourcegraph/sourcegraph/lib/errors"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 )
 
 func setupMockGSClient(t *testing.T, wantRev api.CommitID, returnErr error, hunks []*gitserver.Hunk) gitserver.Client {
@@ -122,19 +122,7 @@ func TestStreamBlame(t *testing.T) {
 		backend.Mocks.Repos = backend.MockRepos{}
 	})
 
-	ffs := featureflag.NewMemoryStore(nil, nil, map[string]bool{"enable-streaming-git-blame": true})
-	ctx := featureflag.WithFlags(context.Background(), ffs)
-
-	t.Run("NOK feature flag disabled", func(t *testing.T) {
-		rec := httptest.NewRecorder()
-		req, err := http.NewRequest(http.MethodGet, "/no-vars", nil)
-		require.NoError(t, err)
-		req = req.WithContext(context.Background()) // no feature flag there
-
-		gsClient := setupMockGSClient(t, "abcd", nil, hunks)
-		handleStreamBlame(logger, db, gsClient).ServeHTTP(rec, req)
-		assert.Equal(t, http.StatusNotFound, rec.Code)
-	})
+	ctx := context.Background()
 
 	t.Run("NOK no mux vars", func(t *testing.T) {
 		rec := httptest.NewRecorder()