[12/x][move-package/lock] Use DependencyGraph in download_dependency_…

…repos

Another occasion where the previous implementation recursively
traversed the transitive dependency graph -- the new approach
discovers the graph and then iterates through its nodes to download
them.

The second step is currently technically unnecessary, but becomes
relevant in the presence of externally resolved dependencies where
third-party resolvers can introduce sub-graphs into the
`DependencyGraph` without having to explore them locally.

Test Plan:

```
move/language/tools/move-package$ cargo nextest
```

language/tools/move-package/src/resolution/mod.rs

@@ -2,30 +2,26 @@
 // Copyright (c) The Move Contributors
 // SPDX-License-Identifier: Apache-2.0
 
-use anyhow::{Context, Result};
+use anyhow::Result;
 use colored::Colorize;
 use move_command_line_common::env::MOVE_HOME;
 use std::{
     ffi::OsStr,
-    fs,
     io::Write,
     path::{Path, PathBuf},
     process::{Command, Stdio},
 };
 
 use crate::{
     package_hooks,
-    source_package::{
-        layout::SourcePackageLayout,
-        manifest_parser::{parse_move_manifest_string, parse_source_manifest},
-        parsed_manifest::{
-            CustomDepInfo, Dependencies, Dependency, DependencyKind, GitInfo, PackageName,
-            SourceManifest,
-        },
+    source_package::parsed_manifest::{
+        CustomDepInfo, DependencyKind, GitInfo, PackageName, SourceManifest,
     },
     BuildConfig,
 };
 
+use self::dependency_graph::DependencyGraph;
+
 pub mod dependency_graph;
 mod digest;
 pub mod lock_file;
@@ -38,50 +34,36 @@ pub fn download_dependency_repos<Progress: Write>(
     root_path: &Path,
     progress_output: &mut Progress,
 ) -> Result<()> {
-    // include dev dependencies if in dev mode
-    let empty_deps;
-    let additional_deps = if build_options.dev_mode {
-        &manifest.dev_dependencies
-    } else {
-        empty_deps = Dependencies::new();
-        &empty_deps
-    };
+    let graph = DependencyGraph::new(
+        manifest,
+        root_path.to_path_buf(),
+        build_options.skip_fetch_latest_git_deps,
+        progress_output,
+    )?;
+
+    for pkg_name in graph.topological_order() {
+        if pkg_name == graph.root_package {
+            continue;
+        }
+
+        if !(build_options.dev_mode || graph.always_deps.contains(&pkg_name)) {
+            continue;
+        }
+
+        let package = graph
+            .package_table
+            .get(&pkg_name)
+            .expect("Metadata for package");
 
-    for (dep_name, dep) in manifest.dependencies.iter().chain(additional_deps.iter()) {
         download_and_update_if_remote(
-            *dep_name,
-            &dep.kind,
+            pkg_name,
+            &package.kind,
             build_options.skip_fetch_latest_git_deps,
             progress_output,
         )?;
-
-        let (dep_manifest, _) = parse_package_manifest(dep, dep_name, root_path.to_path_buf())
-            .with_context(|| format!("While processing dependency '{}'", *dep_name))?;
-        // download dependencies of dependencies
-        download_dependency_repos(&dep_manifest, build_options, root_path, progress_output)?;
     }
-    Ok(())
-}
-
-fn parse_package_manifest(
-    dep: &Dependency,
-    dep_name: &PackageName,
-    mut root_path: PathBuf,
-) -> Result<(SourceManifest, PathBuf)> {
-    root_path.push(local_path(&dep.kind));
-    let manifest_path = root_path.join(SourcePackageLayout::Manifest.path());
 
-    let contents = fs::read_to_string(&manifest_path).with_context(|| {
-        format!(
-            "Unable to find package manifest for '{}' at {:?}",
-            dep_name, manifest_path,
-        )
-    })?;
-
-    let manifest_toml = parse_move_manifest_string(contents)?;
-    let source_package = parse_source_manifest(manifest_toml)?;
-
-    Ok((source_package, root_path))
+    Ok(())
 }
 
 fn download_and_update_if_remote<Progress: Write>(