twitchyliquid64 · Jun 29, 2026 · Jun 29, 2026 · Jun 29, 2026
@@ -34,7 +34,7 @@ pub use profiles::Profile;
 mod decl_tests;
 pub use decl_tests::Test;
 mod stacks;
-pub use stacks::{Stack, StackMatcher};
+pub use stacks::{PackageMatcherPredicate, Stack, StackMatcher};
 
 // Increment for any big change to the format of build specs / stacks, so that hash
 // keys get invalidated.

@@ -217,6 +217,16 @@ impl From<graph::Error> for Error {
     }
 }
 
+impl From<op::Error> for Error {
+    fn from(value: op::Error) -> Self {
+        match value {
+            op::Error::IO(e) => Self::IO("op", PathBuf::new(), e),
+            op::Error::Plan(graph, e) => Self::Plan(Box::new((graph, e))),
+            other => Self::Other(anyhow::anyhow!("{}", other)),
+        }
+    }
+}
+
 impl From<super::ConfigError> for Error {
     fn from(value: super::ConfigError) -> Self {
         Error::Config(value)

@@ -34,6 +34,9 @@ pub use mfile_search_strategy::MFileSearchStrategy;
 mod scaffold;
 pub use scaffold::scaffold_default_mfile;
 
+mod project_setup;
+pub use project_setup::ProjectSetup;
+
 pub use env::Env;
 use tokio::sync::Semaphore;
 use toml_edit::{Array, DocumentMut, Item, TableLike, Value};
@@ -301,6 +304,18 @@ impl Context {
         Self::new(self.config.clone())
     }
 
+    /// Builds a [`ProjectSetup`] from this context, for running project-setup
+    /// operations (e.g. [`op::UpdateProject`]) that refresh the `minimal.toml`.
+    pub fn project_setup(&self) -> ProjectSetup {
+        ProjectSetup::from_parts(
+            self.config.clone(),
+            self.vcs.clone(),
+            self.stdlib_dir.clone(),
+            self.mfile.clone(),
+            self.repo_dir().to_path_buf(),
+        )
+    }
+
     /// Returns a handle to the local cache.
     pub fn local_cache(&self) -> Cache {
         self.cache.clone()

@@ -0,0 +1,115 @@
+//! [`ProjectSetup`]: the `mctx` adapter implementing [`op::ProjectEnv`].
+
+use std::path::{Path, PathBuf};
+
+use checkouts::{GitRef, ManagerHandle as VcsManagerHandle};
+use common::Target;
+use graph::Graph;
+use mfile::LinkConfig;
+
+use crate::{Config, Context, Error, MFileSearchStrategy};
+
+/// The environment project-setup operations ([`op::InitProject`],
+/// [`op::UpdateProject`]) run against.
+///
+/// Unlike [`Context`], this can be constructed without a `minimal.toml` on disk,
+/// which `init` requires when bootstrapping a fresh project.
+pub struct ProjectSetup {
+    config: Config,
+    vcs: VcsManagerHandle,
+    stdlib_dir: PathBuf,
+    mfile: Option<mfile::File>,
+    repo_dir: PathBuf,
+}
+
+impl ProjectSetup {
+    /// Builds an environment for `init`, loading a `minimal.toml` if one is
+    /// already present (the user may be re-initializing).
+    pub fn for_init(config: Config) -> Result<Self, Error> {
+        let (vcs, _cache, stdlib_dir) = Context::sub_setup(&config)?;
+        let strategy = match config.repo_dir_override() {
+            Some(path) => MFileSearchStrategy::Override(path.to_path_buf()),
+            None => MFileSearchStrategy::CurrentDirOnly,
+        };
+        let mfile = match strategy.find_mfile() {
+            Ok(m) => Some(m),
+            Err(Error::MFile(mfile::Error::NotFound)) => None,
+            Err(e) => return Err(e),
+        };
+        let repo_dir = resolve_repo_dir(&config, mfile.as_ref())?;
+        Ok(Self {
+            config,
+            vcs,
+            stdlib_dir,
+            mfile,
+            repo_dir,
+        })
+    }
+
+    /// Builds an environment from the parts of an existing [`Context
8000
`].
+    pub(crate) fn from_parts(
+        config: Config,
+        vcs: VcsManagerHandle,
+        stdlib_dir: PathBuf,
+        mfile: mfile::File,
+        repo_dir: PathBuf,
+    ) -> Self {
+        Self {
+            config,
+            vcs,
+            stdlib_dir,
+            mfile: Some(mfile),
+            repo_dir,
+        }
+    }
+}
+
+/// Resolves the project root: the minimal file's repo, else the configured
+/// override, else the current directory.
+fn resolve_repo_dir(config: &Config, mfile: Option<&mfile::File>) -> Result<PathBuf, Error> {
+    if let Some(p) = mfile.and_then(|m| m.repo_path()) {
+        return Ok(p.to_path_buf());
+    }
+    if let Some(p) = config.repo_dir_override() {
+        return Ok(p.to_path_buf());
+    }
+    std::env::current_dir().map_err(|e| Error::IO("Getting current directory", PathBuf::new(), e))
+}
+
+impl op::ProjectEnv for ProjectSetup {
+    fn repo_dir(&self) -> &Path {
+        &self.repo_dir
+    }
+
+    fn minimal_file(&self) -> Option<&mfile::File> {
+        self.mfile.as_ref()
+    }
+
+    fn checkout_branch(&mut self, repo: &str, branch: &str) -> Result<String, op::Error> {
+        self.vcs
+            .checkout_of(repo, GitRef::Branch(branch.to_string()))
+            .map(|(_dir, rev)| rev)
+            .map_err(|e| op::Error::Other(anyhow::Error::from(e)))
+    }
+
+    fn update_checkouts(&mut self) -> Result<(), op::Error> {
+        self.vcs
+            .update()
+            .map_err(|e| op::Error::Other(anyhow::Error::from(e)))
+    }
+
+    fn graph_from_chain(&mut self, link: LinkConfig, target: Target) -> Result<Graph, op::Error> {
+        Graph::new_from_chain(
+            self.vcs.clone(),
+            &mut graph::LayerCacheDir(self.config.layer_cache_dir()),
+            link,
+            self.stdlib_dir.clone(),
+            target,
+        )
+        .map_err(|e| op::Error::Other(anyhow::anyhow!("loading package graph: {e:?}")))
+    }
+
+    fn invalidate_remote_index(&mut self) {
+        std::fs::remove_file(self.config.index_dir().join(rcache::INDEX_FILENAME)).ok();
+    }
+}