gitimport: Make bookmark generation >10x faster for already imported …

…tags

Summary:
I noticed when re-importing `whatsapp/voip` (which has ~2k tags) that even though most tags were already imported,
it took multiple seconds to iterate over each one with `generate-bookmark`.

Looking at the code, we used to upload the git tag objects every time, even if the tag
already existed.
That's at least two blobstore puts, which explains the  delay.

After this change, the speed is closer to ~5-10 tags per second, as expected.

We could still optimize further by parallelizing the bookmark generation, but this diff
only fixes an obvious pessimization.

Reviewed By: YousefSalama

Differential Revision: D54684266

fbshipit-source-id: 5cddcbc7164a84f81fba184e0d83f6226d41a035

eden/mononoke/git/gitimport/src/main.rs

@@ -5,6 +5,8 @@
  * GNU General Public License version 2.
  */
 
+#![feature(async_closure)]
+
 mod mem_writes_changesets;
 use std::collections::HashMap;
 use std::path::Path;
@@ -368,15 +370,18 @@ async fn async_main(app: MononokeApp) -> Result<(), Error> {
                     // Skip the HEAD revision: it shouldn't be imported as a bookmark in mononoke
                     continue;
                 }
-                if let Some(tag_id) = maybe_tag_id {
-                    // The ref getting imported is a tag, so store the raw git Tag object.
-                    upload_git_tag(&ctx, &uploader, path, &prefs, tag_id).await?;
-                    // Create the changeset corresponding to the commit pointed to by the tag.
-                    create_changeset_for_annotated_tag(
-                        &ctx, &uploader, path, &prefs, tag_id, changeset,
-                    )
-                    .await?;
-                }
+                let upload_if_tag = async {
+                    if let Some(tag_id) = maybe_tag_id {
+                        // The ref getting imported is a tag, so store the raw git Tag object.
+                        upload_git_tag(&ctx, &uploader, path, &prefs, tag_id).await?;
+                        // Create the changeset corresponding to the commit pointed to by the tag.
+                        create_changeset_for_annotated_tag(
+                            &ctx, &uploader, path, &prefs, tag_id, changeset,
+                        )
+                        .await?;
+                    }
+                    Ok::<_, Error>(())
+                };
                 let bookmark_key = BookmarkKey::new(&name)?;
 
                 let pushvars = if args.bypass_readonly {
@@ -396,6 +401,7 @@ async fn async_main(app: MononokeApp) -> Result<(), Error> {
                     // The bookmark already exists. Instead of creating it, we need to move it.
                     Some(old_changeset) => {
                         if old_changeset != final_changeset {
+                            upload_if_tag.await?;
                             let allow_non_fast_forward = true;
                             repo_context
                                 .move_bookmark(
@@ -420,6 +426,7 @@ async fn async_main(app: MononokeApp) -> Result<(), Error> {
                     }
                     // The bookmark doesn't yet exist. Create it.
                     None => {
+                        upload_if_tag.await?;
                         repo_context
                             .create_bookmark(&bookmark_key, final_changeset, pushvars.as_ref())
                             .await

eden/mononoke/tests/integration/test-gitbundle-mononoke-repo-recursive-tag.t

@@ -130,6 +130,3 @@
   $ rm -rf git_client_repo
   $ git clone "$BUNDLE_PATH" git_client_repo
   Cloning into 'git_client_repo'...
-  fatal: bad object 8963e1f55d1346a07c3aec8c8fc72bf87d0452b1
-  fatal: remote did not send all necessary objects
-  [128]