feat: install missing deps on build

cli/src/cmd/forge/build/mod.rs

@@ -1,11 +1,18 @@
-//! build command
-
+//! Build command
 use crate::{
-    cmd::{forge::watch::WatchArgs, Cmd},
+    cmd::{
+        forge::{
+            install::{self, DependencyInstallOpts},
+            watch::WatchArgs,
+        },
+        Cmd,
+    },
     compile,
+    utils::p_println,
 };
 use clap::Parser;
 use ethers::solc::{Project, ProjectCompileOutput};
+use eyre::WrapErr;
 use foundry_config::{
     figment::{
         self,
@@ -68,6 +75,21 @@ impl Cmd for BuildArgs {
     fn run(self) -> eyre::Result<Self::Output> {
         let project = self.project()?;
 
+        if install::has_missing_dependencies(&project.root()) {
+            // The extra newline is needed, otherwise the compiler output will overwrite the
+            // message
+            p_println!(!self.args.silent => "Missing dependencies found. Installing now.\n");
+            install::install(
+                &project.root(),
+                Vec::new(),
+                DependencyInstallOpts {
+                    // TODO(onbjerg): We should settle on --quiet or --silent.
+                    quiet: self.args.silent,
+                    ..Default::default()
+                },
+            ).wrap_err("Your project has missing dependencies that could not be installed. Please ensure git is installed and available.")?
+        }
+
         if self.args.silent {
             compile::suppress_compile(&project)
         } else {

cli/src/cmd/forge/install.rs

@@ -144,7 +144,22 @@ pub(crate) fn install(
     Ok(())
 }
 
-/// installs the dependency as an ordinary folder instead of a submodule
+/// Checks if any submodules have not been initialized yet.
+///
+/// `git submodule status` will return a new line per submodule in the repository. If any line
+/// starts with `-` then it has not been initialized yet.
+pub fn has_missing_dependencies(root: impl AsRef<Path>) -> bool {
+    Command::new("git")
+        .args(&["submodule", "status"])
+        .current_dir(root)
+        .output()
+        .map(|output| {
+            String::from_utf8_lossy(&output.stdout).lines().any(|line| line.starts_with('-'))
+        })
+        .unwrap_or(false)
+}
+
+/// Installs the dependency as an ordinary folder instead of a submodule
 fn install_as_folder(dep: &Dependency, libs: &Path, target_dir: &str) -> eyre::Result<()> {
     // install the dep
     git_clone(dep, libs, target_dir)?;
@@ -158,7 +173,7 @@ fn install_as_folder(dep: &Dependency, libs: &Path, target_dir: &str) -> eyre::R
     Ok(())
 }
 
-/// installs the dependency as new submodule
+/// Installs the dependency as new submodule
 fn install_as_submodule(
     dep: &Dependency,
     libs: &Path,