Extract ResultingChangesetArgs into common module

Summary:
## This stack
Migrate all commands from megarepo tool CLI to mononoke admin `megarepo` subcommand, so they use mononoke_app + clap 4, instad of old cmdlib + clap-2.

I'll try to do one diff per command.

## This diff

Many commands call a `add_resulting_commit_args` function (or variant) to add arguments for a changeset being created.
In this diff I extract those into a common module, so they can be easily reused.

Reviewed By: liubov-dmitrieva

Differential Revision: D68951264

fbshipit-source-id: 361512dcf10bbd6d9f6f81fffc46861bd88605c7

eden/mononoke/tools/admin/src/commands/megarepo.rs

@@ -5,6 +5,7 @@
  * GNU General Public License version 2.
  */
 
+pub(crate) mod common;
 mod merge;
 mod pushredirection;
 

eden/mononoke/tools/admin/src/commands/megarepo/common.rs

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This software may be used and distributed according to the terms of the
+ * GNU General Public License version 2.
+ */
+
+use anyhow::Error;
+use anyhow::Result;
+use bookmarks::BookmarkKey;
+use megarepolib::common::ChangesetArgs as MegarepoNewChangesetArgs;
+use mononoke_types::DateTime;
+
+#[derive(Debug, clap::Args, Clone)]
+pub(crate) struct ResultingChangesetArgs {
+    #[clap(long, short = 'm')]
+    pub commit_message: String,
+    #[clap(long, short = 'a')]
+    pub commit_author: String,
+
+    #[clap(long = "commit-date-rfc3339")]
+    pub datetime: Option<String>,
+
+    #[clap(
+        long,
+        help = "bookmark to point to resulting commits (no sanity checks, will move existing bookmark, be careful)"
+    )]
+    pub set_bookmark: Option<String>,
+
+    #[clap(long = "mark-public")]
+    pub mark_public: bool,
+}
+
+impl TryInto<MegarepoNewChangesetArgs> for ResultingChangesetArgs {
+    type Error = Error;
+
+    fn try_into(self) -> Result<MegarepoNewChangesetArgs> {
+        let mb_datetime = self
+            .datetime
+            .as_deref()
+            .map_or_else(|| Ok(DateTime::now()), DateTime::from_rfc3339)?;
+
+        let mb_bookmark = self.set_bookmark.map(BookmarkKey::new).transpose()?;
+        let res = MegarepoNewChangesetArgs {
+            message: self.commit_message,
+            author: self.commit_author,
+            datetime: mb_datetime,
+            bookmark: mb_bookmark,
+            mark_public: self.mark_public,
+        };
+        Ok(res)
+    }
+}

eden/mononoke/tools/admin/src/commands/megarepo/merge.rs

@@ -10,7 +10,6 @@ use anyhow::format_err;
 use anyhow::Error;
 use anyhow::Result;
 use bonsai_hg_mapping::BonsaiHgMappingRef;
-use bookmarks::BookmarkKey;
 use cloned::cloned;
 use context::CoreContext;
 use futures::try_join;
@@ -24,9 +23,10 @@ use mononoke_app::args::ChangesetArgs;
 use mononoke_app::args::RepoArgs;
 use mononoke_app::MononokeApp;
 use mononoke_types::ChangesetId;
-use mononoke_types::DateTime;
 use slog::info;
 
+use super::common::ResultingChangesetArgs;
+
 /// Create a merge commit with given parents
 #[derive(Debug, clap::Args)]
 pub struct MergeArgs {
@@ -35,42 +35,8 @@ pub struct MergeArgs {
     #[clap(flatten)]
     pub repo_args: RepoArgs,
 
-    #[clap(long, short = 'm')]
-    pub commit_message: String,
-    #[clap(long, short = 'a')]
-    pub commit_author: String,
-
-    #[clap(long = "commit-date-rfc3339")]
-    pub datetime: Option<String>,
-    #[clap(
-        long,
-        help = "bookmark to point to resulting commits (no sanity checks, will move existing bookmark, be careful)"
-    )]
-    pub set_bookmark: Option<String>,
-
-    #[clap(long = "mark-public")]
-    pub mark_public: bool,
-}
-
-impl TryInto<MegarepoNewChangesetArgs> for MergeArgs {
-    type Error = Error;
-
-    fn try_into(self) -> Result<MegarepoNewChangesetArgs> {
-        let mb_datetime = self
-            .datetime
-            .as_deref()
-            .map_or_else(|| Ok(DateTime::now()), DateTime::from_rfc3339)?;
-
-        let mb_bookmark = self.set_bookmark.map(BookmarkKey::new).transpose()?;
-        let res = MegarepoNewChangesetArgs {
-            message: self.commit_message,
-            author: self.commit_author,
-            datetime: mb_datetime,
-            bookmark: mb_bookmark,
-            mark_public: self.mark_public,
-        };
-        Ok(res)
-    }
+    #[command(flatten)]
+    pub res_cs_args: ResultingChangesetArgs,
 }
 
 async fn fail_on_path_conflicts(
@@ -102,7 +68,7 @@ pub async fn perform_merge(
     repo: Repo,
     first_bcs_id: ChangesetId,
     second_bcs_id: ChangesetId,
-    resulting_changeset_args: MegarepoNewChangesetArgs,
+    res_cs_args: MegarepoNewChangesetArgs,
 ) -> Result<HgChangesetId, Error> {
     cloned!(ctx, repo);
     let (first_hg_cs_id, second_hg_cs_id) = try_join!(
@@ -119,7 +85,7 @@ pub async fn perform_merge(
         &repo,
         vec![first_bcs_id, second_bcs_id],
         Default::default(),
-        resulting_changeset_args,
+        res_cs_args,
     )
     .await
 }
@@ -135,14 +101,14 @@ pub async fn run(ctx: &CoreContext, app: MononokeApp, args: MergeArgs) -> Result
         _ => bail!("Expected exactly two parent commits"),
     };
 
-    let resulting_changeset_args = MegarepoNewChangesetArgs::from(args.try_into()?);
+    let res_cs_args = args.res_cs_args.try_into()?;
 
     perform_merge(
         ctx.clone(),
         repo.clone(),
         first_parent,
         second_parent,
-        resulting_changeset_args,
+        res_cs_args,
     )
     .await
     .map(|_| ())