feat: support --manifest-path to project directory

Allow `pixi --manifest-path <path>` to accept a path to a project
directory. This makes it easier to use pixi when scripting as the script
does not need to know if a project is using pixi.toml or pyproject.toml.

Implements: prefix-dev#2706

src/cli/cli_config.rs

@@ -19,7 +19,7 @@ use std::path::PathBuf;
 /// Project configuration
 #[derive(Parser, Debug, Default, Clone)]
 pub struct ProjectConfig {
-    /// The path to `pixi.toml` or `pyproject.toml`
+    /// The path to `pixi.toml`, `pyproject.toml`, or the project directory
     #[arg(long, global = true)]
     pub manifest_path: Option<PathBuf>,
 }

src/cli/completion.rs

@@ -257,7 +257,7 @@ _arguments "${_arguments_options[@]}" \
   # Runs task in project
   export extern "pixi run" [
     ...task: string           # The pixi task or a task shell command you want to run in the project's environment, which can be an executable in the environment's PATH
-    --manifest-path: string   # The path to `pixi.toml` or `pyproject.toml`
+    --manifest-path: string   # The path to `pixi.toml`, `pyproject.toml`, or the project directory
     --frozen                  # Install the environment as defined in the lockfile, doesn't update lockfile if it isn't up-to-date with the manifest file
     --locked                  # Check if lockfile is up-to-date before installing the environment, aborts when lockfile isn't up-to-date with the manifest file
     --environment(-e): string # The environment to run the task in

src/cli/snapshots/pixi__cli__completion__tests__nushell_completion.snap

@@ -14,7 +14,7 @@ expression: result
   # Runs task in project
   export extern "pixi run" [
     ...task: string@"nu-complete pixi run"           # The pixi task or a task shell command you want to run in the project's environment, which can be an executable in the environment's PATH
-    --manifest-path: string   # The path to `pixi.toml` or `pyproject.toml`
+    --manifest-path: string   # The path to `pixi.toml`, `pyproject.toml`, or the project directory
     --frozen                  # Install the environment as defined in the lockfile, doesn't update lockfile if it isn't up-to-date with the manifest file
     --locked                  # Check if lockfile is up-to-date before installing the environment, aborts when lockfile isn't up-to-date with the manifest file
     --environment(-e): string@"nu-complete pixi run environment" # The environment to run the task in

src/project/mod.rs

@@ -242,7 +242,21 @@ impl Project {
     /// or any of the parent
     pub fn load_or_else_discover(manifest_path: Option<&Path>) -> miette::Result<Self> {
         let project = match manifest_path {
-            Some(path) => Project::from_path(path)?,
+            Some(path) => {
+                let path = if path.is_dir() {
+                    &find_project_manifest(path).ok_or_else(|| {
+                        miette::miette!(
+                            "could not find {} or {} at directory {}",
+                            consts::PROJECT_MANIFEST,
+                            consts::PYPROJECT_MANIFEST,
+                            path.to_string_lossy()
+                        )
+                    })?
+                } else {
+                    path
+                };
+                Project::from_path(path)?
+            }
             None => Project::discover()?,
         };
         Ok(project)