feat: add environment file to environment dir (#1495)

Co-authored-by: Bas Zalmstra <[email protected]>

src/cli/info.rs

@@ -16,7 +16,7 @@ use crate::progress::await_in_progress;
 use crate::project::has_features::HasFeatures;
 use crate::task::TaskName;
 use crate::util::default_channel_config;
-use crate::{config, EnvironmentName, FeatureName, Project};
+use crate::{config, consts, EnvironmentName, FeatureName, Project};
 
 static WIDTH: usize = 18;
 
@@ -385,7 +385,7 @@ pub async fn execute(args: Args) -> miette::Result<()> {
     let info = Info {
         platform: Platform::current().to_string(),
         virtual_packages,
-        version: env!("CARGO_PKG_VERSION").to_string(),
+        version: consts::PIXI_VERSION.to_string(),
         cache_dir: Some(config::get_cache_dir()?),
         cache_size,
         auth_dir: auth_file,

src/cli/self_update.rs

@@ -6,6 +6,7 @@ use std::{
 use flate2::read::GzDecoder;
 use tar::Archive;
 
+use crate::consts;
 use miette::{Context, IntoDiagnostic};
 use reqwest::Client;
 use serde::Deserialize;
@@ -39,7 +40,7 @@ struct GithubReleaseAsset {
 }
 
 fn user_agent() -> String {
-    format!("pixi {}", env!("CARGO_PKG_VERSION"))
+    format!("pixi {}", consts::PIXI_VERSION)
 }
 
 fn default_archive_name() -> Option<String> {
@@ -99,7 +100,7 @@ You can always use `pixi self-update --force` to force the update.",
     let target_version = target_version_json.tag_name.trim_start_matches('v');
 
     // Get the current version of the pixi binary
-    let current_version = env!("CARGO_PKG_VERSION");
+    let current_version = consts::PIXI_VERSION;
 
     // Stop here if the target version is the same as the current version
     if target_version == current_version {

src/consts.rs

@@ -7,6 +7,7 @@ pub const PROJECT_MANIFEST: &str = "pixi.toml";
 pub const PYPROJECT_MANIFEST: &str = "pyproject.toml";
 pub const PROJECT_LOCK_FILE: &str = "pixi.lock";
 pub const PIXI_DIR: &str = ".pixi";
+pub const PIXI_VERSION: &str = env!("CARGO_PKG_VERSION");
 pub const CONFIG_FILE: &str = "config.toml";
 pub const PREFIX_FILE_NAME: &str = "pixi_env_prefix";
 pub const ENVIRONMENTS_DIR: &str = "envs";
@@ -24,6 +25,7 @@ pub const DEFAULT_ENVIRONMENT_NAME: &str = "default";
 /// The default channels to use for a new project.
 pub const DEFAULT_CHANNELS: &[&str] = &["conda-forge"];
 pub const DEFAULT_FEATURE_NAME: &str = DEFAULT_ENVIRONMENT_NAME;
+pub const ENVIRONMENT_FILE_NAME: &str = "pixi";
 
 lazy_static! {
     pub static ref TASK_STYLE: Style = Style::new().blue();

src/environment.rs

@@ -26,7 +26,9 @@ use rattler::{
 use rattler_conda_types::{Platform, PrefixRecord, RepoDataRecord};
 use rattler_lock::{PypiPackageData, PypiPackageEnvironmentData};
 use reqwest_middleware::ClientWithMiddleware;
+use serde::{Deserialize, Serialize};
 use std::convert::identity;
+use std::path::PathBuf;
 use std::{collections::HashMap, io::ErrorKind, path::Path};
 
 /// Verify the location of the prefix folder is not changed so the applied prefix path is still valid.
@@ -159,6 +161,37 @@ fn create_history_file(environment_dir: &Path) -> miette::Result<()> {
     Ok(())
 }
 
+#[derive(Serialize, Deserialize)]
+pub(crate) struct EnvironmentFile {
+    pub(crate) manifest_path: PathBuf,
+    pub(crate) environment_name: String,
+    pub(crate) pixi_version: String,
+}
+/// Write information about the environment to a file in the environment directory.
+/// This can be useful for other tools that only know the environment directory to find the original project.
+pub fn write_environment_file(
+    environment_dir: &Path,
+    env_file: EnvironmentFile,
+) -> miette::Result<PathBuf> {
+    let path = environment_dir
+        .join("conda-meta")
+        .join(consts::ENVIRONMENT_FILE_NAME);
+
+    let parent = path
+        .parent()
+        .expect("There should already be a conda-meta folder");
+
+    std::fs::create_dir_all(parent).into_diagnostic()?;
+
+    // Using json as it's easier to machine read it.
+    let contents = serde_json::to_string_pretty(&env_file).into_diagnostic()?;
+    std::fs::write(&path, contents).into_diagnostic()?;
+
+    tracing::debug!("Wrote environment file to: {:?}", path);
+
+    Ok(path)
+}
+
 /// Runs the following checks to make sure the project is in a sane state:
 ///     1. It verifies that the prefix location is unchanged.
 ///     2. It verifies that the system requirements are met.

src/lock_file/update.rs

@@ -27,6 +27,7 @@ use tracing::Instrument;
 use url::Url;
 use uv_normalize::ExtraName;
 
+use crate::environment::{write_environment_file, EnvironmentFile};
 use crate::{
     config, consts,
     environment::{
@@ -113,6 +114,16 @@ impl<'p> LockFileDerivedData<'p> {
 
     /// Returns the up-to-date prefix for the given environment.
     pub async fn prefix(&mut self, environment: &Environment<'p>) -> miette::Result<Prefix> {
+        // Save an environment file to the environment directory
+        write_environment_file(
+            &environment.dir(),
+            EnvironmentFile {
+                manifest_path: environment.project().manifest_path(),
+                environment_name: environment.name().to_string(),
+                pixi_version: consts::PIXI_VERSION.to_string(),
+            },
+        )?;
+
         if let Some(prefix) = self.updated_pypi_prefixes.get(environment) {
             return Ok(prefix.clone());
         }

tests/install_tests.rs

@@ -12,7 +12,7 @@ use pixi::cli::run::Args;
 use pixi::cli::{run, LockFileUsageArgs};
 use pixi::config::{Config, DetachedEnvironments};
 use pixi::consts::{DEFAULT_ENVIRONMENT_NAME, PIXI_UV_INSTALLER};
-use pixi::FeatureName;
+use pixi::{consts, FeatureName};
 use rattler_conda_types::Platform;
 use serial_test::serial;
 use tempfile::TempDir;
@@ -47,6 +47,14 @@ async fn install_run_python() {
     assert_eq!(result.exit_code, 0);
     assert_eq!(result.stdout.trim(), "Python 3.11.0");
     assert!(result.stderr.is_empty());
+
+    // Test for existence of environment file
+    assert!(pixi
+        .default_env_path()
+        .unwrap()
+        .join("conda-meta")
+        .join(consts::ENVIRONMENT_FILE_NAME)
+        .exists())
 }
 
 /// This is a test to check that creating incremental lock files works.