fix(forge): run git submodule sync when installing (#10347)

Author: grandizzy

crates/cli/src/utils/mod.rs

@@ -575,6 +575,10 @@ ignore them in the `.gitignore` file."
         self.cmd().stderr(self.stderr()).args(["submodule", "init"]).exec().map(drop)
     }
 
+    pub fn submodule_sync(self) -> Result<()> {
+        self.cmd().stderr(self.stderr()).args(["submodule", "sync"]).exec().map(drop)
+    }
+
     pub fn cmd(self) -> Command {
         let mut cmd = Self::cmd_no_root();
         cmd.current_dir(self.root);

crates/forge/src/cmd/install.rs

@@ -276,6 +276,9 @@ impl Installer<'_> {
             std::iter::empty::<PathBuf>(),
         )?;
 
+        // sync submodules config with changes in .gitmodules, see <https://github.com/foundry-rs/foundry/issues/9611>
+        self.git.root(path).submodule_sync()?;
+
         if self.commit {
             self.git.add(Some(path))?;
         }