mercurial_derived_data: make get_hg_changeset_from_bonsai an extension trait

Summary:
Make the free function in `mercurial_derived_data` into an extension trait that will work
on any kind of repo that supports derived data.

The ordinary way to get a mercurial changeset with facet-based repos would be:
```
   use repo_derived_data::RepoDerivedDataRef;
   use mercurial_derived_data::MappedHgChangesetId;

   let hg_changeset_id = repo
        .repo_derived_data()
        .derive::<MappedHgChangsetId>(ctx, cs_id)
        .await?
        .hg_changeset_id();
```

However, this is a bit of a mouthful for something that is very common in Mononoke.  Instead,
make it similar to how `BlobRepo` works by turning it into an extension trait:
```
   use mercurial_derived_data::DeriveHgChangeset;

   let hg_changeset_id = repo.derive_hg_changeset(ctx, cs_id).await?;
```

The method name is changed to make it clear that derivation may be triggered,
and `BlobRepo::get_hg_from_bonsai_changeset` is changed to use this new
method.

Reviewed By: mitrandir77

Differential Revision: D34971450

fbshipit-source-id: 890d106278e339c2a6deb973eea8ed5122baa4f8

eden/mononoke/blobrepo/blobrepo_hg/src/lib.rs

@@ -39,6 +39,7 @@ use futures::{
     stream::{self, BoxStream},
     Stream, StreamExt, TryFutureExt, TryStreamExt,
 };
+use mercurial_derived_data::DeriveHgChangeset;
 use mercurial_mutation::ArcHgMutationStore;
 use mercurial_types::{HgChangesetId, HgFileNodeId};
 use mononoke_types::{ChangesetId, RepoPath};
@@ -397,7 +398,7 @@ impl BlobRepoHg for BlobRepo {
         ctx: CoreContext,
         bcs_id: ChangesetId,
     ) -> Result<HgChangesetId, Error> {
-        mercurial_derived_data::get_hg_from_bonsai_changeset(self.clone(), ctx, bcs_id).await
+        self.derive_hg_changeset(&ctx, bcs_id).await
     }
 }
 

eden/mononoke/derived_data/mercurial_derived_data/Cargo.toml

@@ -13,7 +13,6 @@ path = "lib.rs"
 [dependencies]
 anyhow = "1.0.51"
 async-trait = "0.1.52"
-blobrepo = { version = "0.1.0", path = "../../blobrepo" }
 blobrepo_common = { version = "0.1.0", path = "../../blobrepo/common" }
 blobrepo_errors = { version = "0.1.0", path = "../../blobrepo/errors" }
 blobstore = { version = "0.1.0", path = "../../blobstore" }
@@ -28,18 +27,19 @@ futures = { version = "0.3.13", features = ["async-await", "compat"] }
 manifest = { version = "0.1.0", path = "../../manifest" }
 mercurial_types = { version = "0.1.0", path = "../../mercurial/types" }
 mononoke_types = { version = "0.1.0", path = "../../mononoke_types" }
+repo_derived_data = { version = "0.1.0", path = "../../repo_attributes/repo_derived_data" }
 slog = { version = "2.7", features = ["max_level_trace", "nested-values"] }
 sorted_vector_map = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main" }
 stats = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main" }
 tokio = { version = "1.15", features = ["full", "test-util", "tracing"] }
 
 [dev-dependencies]
+blobrepo = { version = "0.1.0", path = "../../blobrepo" }
 blobrepo_hg = { version = "0.1.0", path = "../../blobrepo/blobrepo_hg" }
 bookmarks = { version = "0.1.0", path = "../../bookmarks" }
 fbinit = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main" }
 fbinit-tokio = { version = "0.1.0", git = "https://github.com/facebookexperimental/rust-shed.git", branch = "main" }
 fixtures = { version = "0.1.0", path = "../../tests/fixtures" }
-repo_derived_data = { version = "0.1.0", path = "../../repo_attributes/repo_derived_data" }
 revset = { version = "0.1.0", path = "../../revset" }
 test_repo_factory = { version = "0.1.0", path = "../../repo_factory/test_repo_factory" }
 tests_utils = { version = "0.1.0", path = "../../tests/utils" }

eden/mononoke/derived_data/mercurial_derived_data/derive_hg_changeset.rs

@@ -10,13 +10,13 @@ use crate::{
     mapping::{HgChangesetDeriveOptions, MappedHgChangesetId},
 };
 use anyhow::{anyhow, bail, Error};
-use blobrepo::BlobRepo;
+use async_trait::async_trait;
 use blobrepo_common::changed_files::compute_changed_files;
 use blobstore::{Blobstore, Loadable};
 use borrowed::borrowed;
 use cloned::cloned;
 use context::CoreContext;
-use derived_data::{BonsaiDerived, DeriveError};
+use derived_data_manager::DerivationError;
 use futures::{
     future::{self, try_join, try_join_all},
     stream, FutureExt, TryStreamExt,
@@ -32,6 +32,7 @@ use mercurial_types::{
 use mononoke_types::{
     BonsaiChangeset, ChangesetId, FileChange, FileType, MPath, TrackedFileChange,
 };
+use repo_derived_data::RepoDerivedDataRef;
 use stats::prelude::*;
 use std::sync::Arc;
 use std::{collections::HashMap, time::Instant};
@@ -474,21 +475,38 @@ async fn generate_hg_changeset(
     Ok((csid, cs))
 }
 
-pub async fn get_hg_from_bonsai_changeset(
-    repo: BlobRepo,
-    ctx: CoreContext,
-    bcs_id: ChangesetId,
-) -> Result<HgChangesetId, Error> {
-    STATS::get_hg_from_bonsai_changeset.add_value(1);
-    let start_timestmap = Instant::now();
-    let result = match MappedHgChangesetId::derive(&ctx, &repo, bcs_id).await {
-        Ok(id) => Ok(id.hg_changeset_id()),
-        Err(err) => match err {
-            DeriveError::Disabled(..) => Err(err.into()),
-            DeriveError::Error(err) => Err(err),
-        },
-    };
-    STATS::generate_hg_from_bonsai_total_latency_ms
-        .add_value(start_timestmap.elapsed().as_millis() as i64);
-    result
+#[async_trait]
+pub trait DeriveHgChangeset {
+    async fn derive_hg_changeset(
+        &self,
+        ctx: &CoreContext,
+        cs_id: ChangesetId,
+    ) -> Result<HgChangesetId, Error>;
+}
+
+#[async_trait]
+impl<Repo> DeriveHgChangeset for Repo
+where
+    Repo: RepoDerivedDataRef + Send + Sync,
+{
+    async fn derive_hg_changeset(
+        &self,
+        ctx: &CoreContext,
+        cs_id: ChangesetId,
+    ) -> Result<HgChangesetId, Error> {
+        STATS::get_hg_from_bonsai_changeset.add_value(1);
+        let start_timestamp = Instant::now();
+        let result = match self
+            .repo_derived_data()
+            .derive::<MappedHgChangesetId>(ctx, cs_id)
+            .await
+        {
+            Ok(id) => Ok(id.hg_changeset_id()),
+            Err(err @ DerivationError::Disabled(..)) => Err(err.into()),
+            Err(DerivationError::Error(err)) => Err(err),
+        };
+        STATS::generate_hg_from_bonsai_total_latency_ms
+            .add_value(start_timestamp.elapsed().as_millis() as i64);
+        result
+    }
 }

eden/mononoke/derived_data/mercurial_derived_data/lib.rs

@@ -11,6 +11,6 @@ pub mod derive_hg_changeset;
 pub mod derive_hg_manifest;
 mod mapping;
 
-pub use derive_hg_changeset::{get_hg_from_bonsai_changeset, get_manifest_from_bonsai};
+pub use derive_hg_changeset::{get_manifest_from_bonsai, DeriveHgChangeset};
 pub use derive_hg_manifest::derive_hg_manifest;
 pub use mapping::MappedHgChangesetId;