Respect submodule update=none strategy in .gitmodules

crates/cargo-test-support/src/compare.rs

@@ -196,6 +196,7 @@ fn substitute_macros(input: &str) -> String {
  ("[OWNER]", " Owner"),
  ("[MIGRATING]", " Migrating"),
  ("[EXECUTABLE]", " Executable"),
+ ("[SKIPPING]", " Skipping"),
  ];
  let mut result = input.to_owned();
  for &(pat, subst) in &macros {

src/cargo/sources/git/utils.rs

@@ -370,6 +370,18 @@ impl<'a> GitCheckout<'a> {
  anyhow::format_err!("non-utf8 url for submodule {:?}?", child.path())
  })?;
 
+ // Skip the submodule if the config says not to update it.
+ if child.update_strategy() == git2::SubmoduleUpdate::None {
+ cargo_config.shell().status(
+ "Skipping",
+ format!(
+ "git submodule `{}` due to update strategy in .gitmodules",
+ url
+ ),
+ )?;
+ return Ok(());
+ }
+
  // A submodule which is listed in .gitmodules but not actually
  // checked out will not have a head id, so we should ignore it.
  let head = match child.head_id() {

tests/testsuite/git.rs

@@ -1023,6 +1023,60 @@ Caused by:
  .run();
 }
 
+#[cargo_test]
+fn dep_with_skipped_submodule() {
+ // Ensure we skip dependency submodules if their update strategy is `none`.
+ let qux = git::new("qux", |project| {
+ project.no_manifest().file("README", "skip me")
+ });
+
+ let bar = git::new("bar", |project| {
+ project
+ .file("Cargo.toml", &basic_manifest("bar", "0.0.0"))
+ .file("src/lib.rs", "")
+ });
+
+ // `qux` is a submodule of `bar`, but we don't want to update it.
+ let repo = git2::Repository::open(&bar.root()).unwrap();
+ git::add_submodule(&repo, qux.url().as_str(), Path::new("qux"));
+
+ let mut conf = git2::Config::open(&bar.root().join(".gitmodules")).unwrap();
+ conf.set_str("submodule.qux.update", "none").unwrap();
+
+ git::add(&repo);
+ git::commit(&repo);
+
+ let foo = project()
+ .file(
+ "Cargo.toml",
+ &format!(
+ r#"
+ [project]
+ name = "foo"
+ version = "0.0.0"
+ authors = []
+
+ [dependencies.bar]
+ git = "{}"
+ "#,
+ bar.url()
+ ),
+ )
+ .file("src/main.rs", "fn main() {}")
+ .build();
+
+ foo.cargo("build")
+ .with_stderr(
+ "\
+[UPDATING] git repository `file://[..]/bar`
+[SKIPPING] git submodule `file://[..]/qux` [..]
+[COMPILING] bar [..]
+[COMPILING] foo [..]
+[FINISHED] dev [unoptimized + debuginfo] target(s) in [..]\n",
+ )
+ .run();
+}
+
 #[cargo_test]
 fn dep_ambiguous() {
  let project = project();