Add Support for Submodule Versioning

.gitmodules

@@ -0,0 +1,6 @@
+[submodule "test-child-repo"]
+	path = test-child-repo
+	url = [email protected]:baxterjo/test-child-repo.git
+[submodule "test_outer_directory/test-child-repo"]
+	path = test_outer_directory/test-child-repo
+	url = [email protected]:baxterjo/test-child-repo.git

git-version-macro/src/describe_submodules.rs

@@ -0,0 +1,165 @@
+extern crate proc_macro;
+use crate::canonicalize_path;
+use crate::git_dependencies;
+use crate::utils::run_git;
+use proc_macro2::{Span, TokenStream as TokenStream2};
+use quote::{quote, ToTokens};
+use std::ffi::OsStr;
+use std::path::Path;
+use std::process::Command;
+use syn::{
+	bracketed,
+	parse::{Parse, ParseStream},
+	punctuated::Punctuated,
+	token::{Comma, Eq},
+	Expr, Ident, LitStr,
+};
+
+macro_rules! error {
+	($($args:tt)*) => {
+		syn::Error::new(Span::call_site(), format!($($args)*))
+	};
+}
+
+#[derive(Default)]
+pub(crate) struct GitModArgs {
+	args: Option<Punctuated<LitStr, Comma>>,
+	prefix: Option<LitStr>,
+	suffix: Option<LitStr>,
+	fallback: Option<Expr>,
+}
+
+impl Parse for GitModArgs {
+	fn parse(input: ParseStream) -> syn::Result<Self> {
+		let mut result = GitModArgs::default();
+		loop {
+			if input.is_empty() {
+				break;
+			}
+			let ident: Ident = input.parse()?;
+			let _: Eq = input.parse()?;
+			let check_dup = |dup: bool| {
+				if dup {
+					Err(error!("`{} = ` can only appear once", ident))
+				} else {
+					Ok(())
+				}
+			};
+			match ident.to_string().as_str() {
+				"args" => {
+					check_dup(result.args.is_some())?;
+					let content;
+					bracketed!(content in input);
+					result.args = Some(Punctuated::parse_terminated(&content)?);
+				}
+				"prefix" => {
+					check_dup(result.prefix.is_some())?;
+					result.prefix = Some(input.parse()?);
+				}
+				"suffix" => {
+					check_dup(result.suffix.is_some())?;
+					result.suffix = Some(input.parse()?);
+				}
+				"fallback" => {
+					check_dup(result.fallback.is_some())?;
+					result.fallback = Some(input.parse()?);
+				}
+				x => Err(error!("Unexpected argument name `{}`", x))?,
+			}
+			if input.is_empty() {
+				break;
+			}
+			let _: Comma = input.parse()?;
+		}
+		Ok(result)
+	}
+}
+
+pub(crate) fn git_version_modules_impl(args: GitModArgs) -> syn::Result<TokenStream2> {
+	let modules = match get_modules() {
+		Ok(x) => x,
+		Err(err) => return Err(error!("{}", err)),
+	};
+
+	let mut describe_paths: Vec<(String, String)> = vec![];
+
+	for path in modules.into_iter() {
+		let path_obj = Path::new(&path);
+		let path_obj = canonicalize_path(path_obj)?;
+		describe_paths.push((path, path_obj));
+	}
+
+	let git_describe_args = args.args.map_or_else(
+		|| vec!["--always".to_string(), "--dirty=-modified".to_string()],
+		|list| list.iter().map(|x| x.value()).collect(),
+	);
+
+	let prefix = match args.prefix {
+		Some(x) => x.value(),
+		_ => "".to_string(),
+	};
+	let suffix = match args.suffix {
+		Some(x) => x.value(),
+		_ => "".to_string(),
+	};
+
+	match describe_modules(describe_paths, &git_describe_args, prefix, suffix) {
+		Ok(result) => {
+			let dependencies = git_dependencies()?;
+			let (paths, versions) = result;
+
+			Ok(quote!({
+				#dependencies;
+
+				[#((#paths, #versions)),*]
+
+			}))
+		}
+		Err(_) if args.fallback.is_some() => Ok(args.fallback.to_token_stream()),
+		Err(e) => Err(error!("{}", e)),
+	}
+}
+
+/// Run `git submodule foreach` command to discover submodules in the project.
+fn get_modules() -> Result<Vec<String>, String> {
+	let mut args: Vec<String> = "submodule foreach --quiet --recursive"
+		.to_string()
+		.split(' ')
+		.map(|x| x.to_string())
+		.collect();
+
+	args.push("echo $displaypath".to_string());
+
+	let result = run_git("git submodule", Command::new("git").args(args))?;
+
+	Ok(result.split('\n').map(|x| x.to_string()).collect())
+}
+
+/// Run `git describe` for each submodule to
+fn describe_modules<I, S>(
+	paths: Vec<(String, String)>,
+	describe_args: I,
+	prefix: String,
+	suffix: String,
+) -> Result<(Vec<String>, Vec<String>), String>
+where
+	I: IntoIterator<Item = S> + Clone,
+	S: AsRef<OsStr>,
+{
+	let mut paths_out: Vec<String> = vec![];
+	let mut versions: Vec<String> = vec![];
+
+	for (rel_path, abs_path) in paths.into_iter() {
+		let result = run_git(
+			"git describe",
+			Command::new("git")
+				.current_dir(abs_path)
+				.arg("describe")
+				.args(describe_args.clone()),
+		)?;
+		paths_out.push(rel_path);
+		versions.push(format!("{}{}{}", prefix, result, suffix))
+	}
+
+	Ok((paths_out, versions))
+}

git-version-macro/src/lib.rs

@@ -6,7 +6,7 @@ use syn::parse::{Parse, ParseStream};
 use syn::punctuated::Punctuated;
 use syn::token::{Comma, Eq};
 use syn::{Expr, Ident, LitStr};
-
+pub(crate) mod describe_submodules;
 mod utils;
 use self::utils::{describe_cwd, git_dir_cwd};
 
@@ -17,8 +17,7 @@ macro_rules! error {
 }
 
 fn canonicalize_path(path: &Path) -> syn::Result<String> {
-	path
-		.canonicalize()
+	path.canonicalize()
 		.map_err(|e| error!("failed to canonicalize {}: {}", path.display(), e))?
 		.into_os_string()
 		.into_string()
@@ -29,12 +28,18 @@ fn canonicalize_path(path: &Path) -> syn::Result<String> {
 fn git_dependencies() -> syn::Result<TokenStream2> {
 	let git_dir = git_dir_cwd().map_err(|e| error!("failed to determine .git directory: {}", e))?;
 
-	let deps: Vec<_> = ["logs/HEAD", "index"].iter().flat_map(|&file| {
-		canonicalize_path(&git_dir.join(file)).map(Some).unwrap_or_else(|e|  {
-			eprintln!("Failed to add dependency on the git state: {}. Git state changes might not trigger a rebuild.", e);
-			None
+	let deps: Vec<_> = ["logs/HEAD", "index"]
+		.iter()
+		.flat_map(|&file| {
+			canonicalize_path(&git_dir.join(file)).map(Some).unwrap_or_else(|e| {
+				eprintln!(
+					"Failed to add dependency on the git state: {}. Git state changes might not trigger a rebuild.",
+					e
+				);
+				None
+			})
 		})
-	}).collect();
+		.collect();
 
 	Ok(quote! {
 		#( include_bytes!(#deps); )*
@@ -55,7 +60,9 @@ impl Parse for Args {
 	fn parse(input: ParseStream) -> syn::Result<Self> {
 		let mut result = Args::default();
 		loop {
-			if input.is_empty() { break; }
+			if input.is_empty() {
+				break;
+			}
 			let ident: Ident = input.parse()?;
 			let _: Eq = input.parse()?;
 			let check_dup = |dup: bool| {
@@ -94,7 +101,9 @@ impl Parse for Args {
 				}
 				x => Err(error!("Unexpected argument name `{}`", x))?,
 			}
-			if input.is_empty() { break; }
+			if input.is_empty() {
+				break;
+			}
 			let _: Comma = input.parse()?;
 		}
 		Ok(result)
@@ -151,7 +160,7 @@ pub fn git_version(input: TokenStream) -> TokenStream {
 fn git_version_impl(args: Args) -> syn::Result<TokenStream2> {
 	let git_args = args.git_args.map_or_else(
 		|| vec!["--always".to_string(), "--dirty=-modified".to_string()],
-		|list| list.iter().map(|x| x.value()).collect()
+		|list| list.iter().map(|x| x.value()).collect(),
 	);
 
 	let cargo_fallback = args.cargo_prefix.is_some() || args.cargo_suffix.is_some();
@@ -170,20 +179,62 @@ fn git_version_impl(args: Args) -> syn::Result<TokenStream2> {
 			if let Ok(version) = std::env::var("CARGO_PKG_VERSION") {
 				let prefix = args.cargo_prefix.iter();
 				let suffix = args.cargo_suffix;
-				Ok(quote!(
-					concat!(#(#prefix,)* #version, #suffix)
-				))
+				Ok(quote!(concat!(#(#prefix,)* #version, #suffix)))
 			} else if let Some(fallback) = args.fallback {
 				Ok(fallback.to_token_stream())
 			} else {
 				Err(error!("Unable to get git or cargo version"))
 			}
 		}
-		Err(_) if args.fallback.is_some() => {
-			Ok(args.fallback.to_token_stream())
-		}
-		Err(e) => {
-			Err(error!("{}", e))
-		}
+		Err(_) if args.fallback.is_some() => Ok(args.fallback.to_token_stream()),
+		Err(e) => Err(error!("{}", e)),
 	}
 }
+
+/// Get the git version for submodules below the cargo project.
+///
+/// This is achieved by running `git foreach` in tandem with `git describe`.
+/// The arguments for `git describe` are exposed as macro arguments.
+///
+/// This macro expands to an array of `(&str, &str)` tuples that look like the following:
+///
+/// `[("relative/path/to/submodule", "{prefix}{git_describe_output}{suffix}")]`
+///
+/// The following (named) arguments can be given:
+///
+/// - `args`: The arguments to call `git describe` with.
+///   Default: `args = ["--always", "--dirty=-modified"]`
+///
+/// - `prefix`, `suffix`:
+///   The git version for each submodule will be prefixed/suffixed
+///   by these strings.
+///
+/// - `fallback`:
+///   If all else fails, this string will be given instead of reporting an
+///   error.
+///
+/// # Examples
+///
+/// ```
+/// const MODULE_VERSIONS: [(&str, &str), N] = git_version_modules!();
+/// ```
+///
+/// ```
+/// const MODULE_VERSIONS: [(&str, &str), N] = git_version_modules!(args = ["--abbrev=40", "--always"]);
+/// ```
+///
+/// ```
+/// # use git_version::git_version_modules;
+/// const MODULE_VERSIONS: [(&str, &str), N] = git_version_modules!(prefix = "git:", fallback = "unknown");
+/// ```
+#[proc_macro]
+pub fn git_version_modules(input: TokenStream) -> TokenStream {
+	let args = syn::parse_macro_input!(input as describe_submodules::GitModArgs);
+
+	let tokens = match describe_submodules::git_version_modules_impl(args) {
+		Ok(x) => x,
+		Err(e) => e.to_compile_error(),
+	};
+
+	TokenStream::from(tokens)
+}

git-version-macro/src/utils.rs

@@ -17,7 +17,7 @@ pub fn git_dir_cwd() -> Result<PathBuf, String> {
 	Ok(PathBuf::from(path))
 }
 
-fn run_git(program: &str, command: &mut std::process::Command) -> Result<String, String> {
+pub(crate) fn run_git(program: &str, command: &mut std::process::Command) -> Result<String, String> {
 	let output = command
 		.stdout(std::process::Stdio::piped())
 		.stderr(std::process::Stdio::piped())
@@ -34,8 +34,8 @@ fn run_git(program: &str, command: &mut std::process::Command) -> Result<String,
 
 	let output = collect_output(program, output)?;
 	let output = strip_trailing_newline(output);
-	let output = String::from_utf8(output)
-		.map_err(|_| format!("Failed to parse output of `{}`: output contains invalid UTF-8", program))?;
+	let output =
+		String::from_utf8(output).map_err(|_| format!("Failed to parse output of `{}`: output contains invalid UTF-8", program))?;
 	Ok(output)
 }
 
@@ -48,7 +48,9 @@ fn collect_output(program: &str, output: std::process::Output) -> Result<Vec<u8>
 	// If the command terminated with non-zero exit code, return an error.
 	} else if let Some(status) = output.status.code() {
 		// Include the first line of stderr in the error message, if it's valid UTF-8 and not empty.
-		let message = output.stderr.split(|c| *c == b'\n')
+		let message = output
+			.stderr
+			.split(|c| *c == b'\n')
 			.next()
 			.and_then(|x| std::str::from_utf8(x).ok())
 			.filter(|x| !x.is_empty());
@@ -82,8 +84,8 @@ fn strip_trailing_newline(mut input: Vec<u8>) -> Vec<u8> {
 
 #[test]
 fn test_git_dir() {
-	use std::path::Path;
 	use assert2::{assert, let_assert};
+	use std::path::Path;
 
 	let_assert!(Ok(git_dir) = git_dir_cwd());
 	let_assert!(Ok(git_dir) = git_dir.canonicalize());

src/lib.rs

@@ -13,7 +13,7 @@
 //! These macros do not depend on libgit, but simply uses the `git` binary directly.
 //! So you must have `git` installed somewhere in your `PATH`.
 
-pub use git_version_macro::git_version;
+pub use git_version_macro::{git_version, git_version_modules};
 
 /// Run `git describe` at compile time with custom flags.
 ///

tests/version.rs

@@ -1,4 +1,4 @@
-use git_version::{git_describe, git_version};
+use git_version::{git_describe, git_version, git_version_modules};
 
 #[test]
 fn git_describe_is_right() {
@@ -14,3 +14,13 @@ fn git_describe_is_right() {
 	assert_eq!(git_describe!("--always", "--dirty=-modified"), name);
 	assert_eq!(git_version!(prefix = "[", suffix = "]"), format!("[{}]", name));
 }
+
+#[test]
+fn test_modules_macro_gives_expected_output() {
+	let module_versions = git_version_modules!(
+		prefix = "pre-",
+		suffix = "-suff",
+		args = ["--always", "--dirty=-modified", "--tags"]
+	);
+	println!("{module_versions:#?}");
+}