feat: support sourceRoot selection

This is now possible to package from a mono-repository, check opentelemetry-python for a usecase.

Author: RaitoBezarius

src/default.nix

@@ -72,6 +72,25 @@ struct Outputs {
     out: String,
 }
 
+fn is_target_for_packaging(src_dir: &PathBuf) -> bool {
+    let has_cargo = src_dir.join("Cargo.toml").is_file();
+    let cargo_lock = File::open(src_dir.join("Cargo.lock"));
+    let has_cargo_lock = cargo_lock.is_ok();
+    let has_cmake = src_dir.join("CMakeLists.txt").is_file();
+    let has_go = src_dir.join("go.mod").is_file();
+    let has_meson = src_dir.join("meson.build").is_file();
+    let pyproject_toml = src_dir.join("pyproject.toml");
+    let has_pyproject = pyproject_toml.is_file();
+    let has_setuptools = src_dir.join("setup.py").is_file();
+
+    (has_cargo && has_cargo_lock)
+        || has_cmake
+        || has_go
+        || has_meson
+        || has_pyproject
+        || has_setuptools
+}
+
 #[tokio::main]
 async fn main() -> Result<()> {
     run().await
@@ -394,7 +413,74 @@ async fn run() -> Result<()> {
         PathBuf::from(&src)
     };
 
-    let mut choices = Vec::new();
+    // Let's first find all subdirectories that are compatible with our supported recipes.
+    let root_src_dir = src_dir.clone();
+    let mut open_subdirs = vec![(0, src_dir)];
+    let mut sourceroot_candidates = vec![];
+    while !open_subdirs.is_empty() {
+        // If we call this, we have a non-empty vector.
+        let (depth, target_dir) = open_subdirs.pop().unwrap();
+        let subdirs = std::fs::read_dir(&target_dir).with_context(|| {
+            format!("failed to list subdirectories of {}", target_dir.display())
+        })?;
+
+        for maybe_subdir in subdirs {
+            let subdir = maybe_subdir.context(format!(
+                "unexpected io error while reading a subdirectory of {}",
+                target_dir.to_string_lossy()
+            ))?;
+
+            let subdir_path = &subdir.path();
+
+            // We want only subdirectories.
+            if !subdir_path.is_dir() {
+                continue;
+            }
+
+            if is_target_for_packaging(subdir_path) {
+                sourceroot_candidates.push(subdir.file_name());
+            }
+
+            // Recurse into that subdir.
+            if depth < 3 {
+                open_subdirs.push((depth + 1, subdir_path.to_path_buf()));
+            }
+        }
+    }
+
+    editor.set_helper(Some(Prompter::List(
+        sourceroot_candidates
+            .iter()
+            .map(|sr| {
+                PathBuf::from(sr).strip_prefix(&root_src_dir)
+                    .expect("Failed to strip the root source directory prefix")
+                    .to_string_lossy()
+                    .to_string()
+            })
+            .collect(),
+    )));
+    let choice = editor.readline(&prompt("Which subdirectory should we use?"))?;
+    let src_dir = &PathBuf::from(choice
+        .parse()
+        .ok()
+        .and_then(|i: usize| sourceroot_candidates.get(i))
+        .unwrap_or_else(|| &sourceroot_candidates[0]));
+    let source_root = if src_dir != &root_src_dir {
+        Some(src_dir)
+    } else {
+        None
+    };
+    let source_root_expr = match source_root {
+        Some(subdir) => format!(
+            "\nsourceRoot = \"source/{}\";",
+            subdir
+                .strip_prefix(&root_src_dir)
+                .expect("Failed to strip the root source directory prefix")
+                .to_string_lossy()
+        ),
+        None => "".to_string(),
+    };
+
     let has_cargo = src_dir.join("Cargo.toml").is_file();
     let cargo_lock = File::open(src_dir.join("Cargo.lock"));
     let has_cargo_lock = cargo_lock.is_ok();
@@ -405,6 +491,7 @@ async fn run() -> Result<()> {
     let has_pyproject = pyproject_toml.is_file();
     let has_setuptools = src_dir.join("setup.py").is_file();
 
+    let mut choices = Vec::new();
     let rust_vendors = if has_cargo {
         if cargo_lock.map_or(true, |file| {
             BufReader::new(file)
@@ -454,7 +541,6 @@ async fn run() -> Result<()> {
     }
 
     choices.push(BuildType::MkDerivation { rust: None });
-
     editor.set_helper(Some(Prompter::Build(choices)));
     let choice = editor.readline(&prompt("How should this package be built?"))?;
     let Some(Prompter::Build(choices)) = editor.helper_mut() else {
@@ -564,7 +650,7 @@ async fn run() -> Result<()> {
                       pname = {pname:?};
                       version = {version:?};
 
-                      src = {src_expr};
+                      src = {src_expr};{source_root_expr}
 
                       vendorHash = {hash};
 
@@ -653,7 +739,7 @@ async fn run() -> Result<()> {
                       version = {version:?};
                       format = "{format}";
 
-                      src = {src_expr};
+                      src = {src_expr};{source_root_expr}
 
                 "#,
                 if application {
@@ -712,7 +798,7 @@ async fn run() -> Result<()> {
                       pname = {pname:?};
                       version = {version:?};
 
-                      src = {src_expr};
+                      src = {src_expr};{source_root_expr}
 
                       cargoHash = "{hash}";
 
@@ -742,7 +828,7 @@ async fn run() -> Result<()> {
                       pname = "{pname}";
                       version = "{version}";
 
-                      src = {src_expr};
+                      src = {src_expr};{source_root_expr}
 
                       cargoLock = "#,
             )?;
@@ -762,6 +848,7 @@ async fn run() -> Result<()> {
                       version = {version:?};
 
                       src = {src_expr};
+                      {source_root_expr}
 
                 "#,
             )?;
@@ -791,7 +878,7 @@ async fn run() -> Result<()> {
                       pname = {pname:?};
                       version = {version:?};
 
-                      src = {src_expr};
+                      src = {src_expr};{source_root_expr}
 
                       cargoDeps = rustPlatform.fetchCargoTarball {{
                         inherit src;
@@ -824,7 +911,7 @@ async fn run() -> Result<()> {
                       pname = "{pname}";
                       version = "{version}";
 
-                      src = {src_expr};
+                      src = {src_expr};{source_root_expr}
 
                       cargoDeps = rustPlatform.importCargoLock "#,
             )?;
@@ -908,7 +995,7 @@ async fn run() -> Result<()> {
     }
 
     let mut desc = desc.trim_matches(|c: char| !c.is_alphanumeric()).to_owned();
-    desc.get_mut(0 .. 1).map(str::make_ascii_uppercase);
+    desc.get_mut(0..1).map(str::make_ascii_uppercase);
     write!(out, "  ")?;
     writedoc!(
         out,
@@ -1022,5 +1109,5 @@ fn get_version(rev: &str) -> &str {
 }
 
 fn get_version_number(rev: &str) -> &str {
-    &rev[rev.find(char::is_numeric).unwrap_or_default() ..]
+    &rev[rev.find(char::is_numeric).unwrap_or_default()..]
 }

src/main.rs

@@ -17,6 +17,7 @@ use crate::{
 #[derive(Helper, Highlighter)]
 pub enum Prompter {
     Path(FilenameCompleter),
+    List(Vec<String>),
     Revision(Revisions),
     NonEmpty,
     YesNo,
@@ -49,6 +50,17 @@ impl Completer for Prompter {
             Prompter::Revision(revisions) => Ok((0, revisions.completions.clone())),
             Prompter::NonEmpty => Ok((0, Vec::new())),
             Prompter::YesNo => Ok((0, Vec::new())),
+            Prompter::List(choices) => Ok((
+                0,
+                choices
+                    .iter()
+                    .enumerate()
+                    .map(|(i, choice)| Pair {
+                        display: format!("{i} - {choice}"),
+                        replacement: i.to_string(),
+                    })
+                    .collect(),
+            )),
             Prompter::Build(choices) => Ok((
                 0,
                 choices
@@ -114,6 +126,16 @@ impl Hinter for Prompter {
 
             Prompter::YesNo => None,
 
+            Prompter::List(choices) => Some(SimpleHint(if line.is_empty() {
+                format_args!("  ({})", choices[0])
+                    .blue()
+                    .italic()
+                    .to_string()
+            } else if let Some(choice) = line.parse().ok().and_then(|i: usize| choices.get(i)) {
+                format_args!("  ({choice})").blue().italic().to_string()
+            } else {
+                "  press <tab> to see options".yellow().italic().to_string()
+            })),
             Prompter::Build(choices) => Some(SimpleHint(if line.is_empty() {
                 format_args!("  ({})", choices[0])
                     .blue()
@@ -157,6 +179,21 @@ impl Validator for Prompter {
 
             Prompter::YesNo => ValidationResult::Valid(None),
 
+            Prompter::List(choices) => {
+                let input = ctx.input();
+                if input.is_empty() {
+                    ValidationResult::Valid(Some(choices[0].to_string()))
+                } else if let Some(choice) = input
+                    .parse::<usize>()
+                    .ok()
+                    .and_then(|choice| choices.get(choice))
+                {
+                    ValidationResult::Valid(Some(format!(" - {choice}")))
+                } else {
+                    ValidationResult::Invalid(None)
+                }
+            }
+
             Prompter::Build(choices) => {
                 let input = ctx.input();
                 if input.is_empty() {