Update workspace manifest with new members.

When a user runs `cargo new` or `cargo init` within a workspace, Cargo will automatically add the new package to the members list in the workspace if necessary. The heuristic to add the new package is as follows:

- If there is no `members` list in the workspace yet, a new `members` list is created.
- If there is an `exclude` statement, Cargo checks if the new package should be excluded. If it doesn't match the `exclude` list, the package is added to the `members` list.
- If there is a glob expression in the `members` list that matches the new package, the package is not added to the `members` list.
- If the existent `members` list is sorted, Cargo tries to preserve the ordering when it adds the new package.

This change doesn't try to format the resulting `members` list in any way, leaving the formatting decissions to the user.

Signed-off-by: David Calavera <[email protected]>

Author: calavera

src/cargo/ops/cargo_new.rs

@@ -1,10 +1,11 @@
 use crate::core::{Edition, Shell, Workspace};
 use crate::util::errors::CargoResult;
 use crate::util::important_paths::find_root_manifest_for_wd;
+use crate::util::toml_mut::is_sorted;
 use crate::util::{existing_vcs_repo, FossilRepo, GitRepo, HgRepo, PijulRepo};
 use crate::util::{restricted_names, Config};
-use anyhow::{anyhow, Context as _};
-use cargo_util::paths;
+use anyhow::{anyhow, Context};
+use cargo_util::paths::{self, write_atomic};
 use serde::de;
 use serde::Deserialize;
 use std::collections::BTreeMap;
@@ -13,6 +14,7 @@ use std::io::{BufRead, BufReader, ErrorKind};
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::{fmt, slice};
+use toml_edit::{Array, Value};
 
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub enum VersionControl {
@@ -809,7 +811,7 @@ fn mk(config: &Config, opts: &MkOptions<'_>) -> CargoResult<()> {
         // Sometimes the root manifest is not a valid manifest, so we only try to parse it if it is.
         // This should not block the creation of the new project. It is only a best effort to
         // inherit the workspace package keys.
-        if let Ok(workspace_document) = root_manifest.parse::<toml_edit::Document>() {
+        if let Ok(mut workspace_document) = root_manifest.parse::<toml_edit::Document>() {
             if let Some(workspace_package_keys) = workspace_document
                 .get("workspace")
                 .and_then(|workspace| workspace.get("package"))
@@ -832,6 +834,13 @@ fn mk(config: &Config, opts: &MkOptions<'_>) -> CargoResult<()> {
                 table["workspace"] = toml_edit::value(true);
                 manifest["lints"] = toml_edit::Item::Table(table);
             }
+
+            // Try to add the new package to the workspace members.
+            update_manifest_with_new_member(
+                &root_manifest_path,
+                &mut workspace_document,
+                opts.path,
+            )?;
         }
     }
 
@@ -931,3 +940,95 @@ fn update_manifest_with_inherited_workspace_package_keys(
         try_remove_and_inherit_package_key(key, manifest);
     }
 }
+
+/// Adds the new package member to the [workspace.members] array.
+/// - It first checks if the name matches any element in [workspace.exclude],
+///  and it ignores the name if there is a match.
+/// - Then it check if the name matches any element already in [workspace.members],
+/// and it ignores the name if there is a match.
+/// - If [workspace.members] doesn't exist in the manifest, it will add a new section
+/// with the new package in it.
+fn update_manifest_with_new_member(
+    root_manifest_path: &Path,
+    workspace_document: &mut toml_edit::Document,
+    package_path: &Path,
+) -> CargoResult<()> {
+    // Find the relative path for the package from the workspace root directory.
+    let workspace_root = root_manifest_path.parent().with_context(|| {
+        format!(
+            "workspace root manifest doesn't have a parent directory `{}`",
+            root_manifest_path.display()
+        )
+    })?;
+    let relpath = pathdiff::diff_paths(package_path, workspace_root).with_context(|| {
+        format!(
+            "path comparison requires two absolute paths; package_path: `{}`, workspace_path: `{}`",
+            package_path.display(),
+            workspace_root.display()
+        )
+    })?;
+
+    let mut components = Vec::new();
+    for comp in relpath.iter() {
+        let comp = comp.to_str().with_context(|| {
+            format!("invalid unicode component in path `{}`", relpath.display())
+        })?;
+        components.push(comp);
+    }
+    let display_path = components.join("/");
+
+    // Don't add the new package to the workspace's members
+    // if there is an exclusion match for it.
+    if let Some(exclude) = workspace_document
+        .get("workspace")
+        .and_then(|workspace| workspace.get("exclude"))
+        .and_then(|exclude| exclude.as_array())
+    {
+        for member in exclude {
+            let pat = member
+                .as_str()
+                .with_context(|| format!("invalid non-string exclude path `{}`", member))?;
+            if pat == display_path {
+                return Ok(());
+            }
+        }
+    }
+
+    // If the members element already exist, check if one of the patterns
+    // in the array already includes the new package's relative path.
+    // - Add the relative path if the members don't match the new package's path.
+    // - Create a new members array if there are no members element in the workspace yet.
+    if let Some(members) = workspace_document
+        .get_mut("workspace")
+        .and_then(|workspace| workspace.get_mut("members"))
+        .and_then(|members| members.as_array_mut())
+    {
+        for member in members.iter() {
+            let pat = member
+                .as_str()
+                .with_context(|| format!("invalid non-string member `{}`", member))?;
+            let pattern = glob::Pattern::new(pat)
+                .with_context(|| format!("cannot build glob pattern from `{}`", pat))?;
+
+            if pattern.matches(&display_path) {
+                return Ok(());
+            }
+        }
+
+        let was_sorted = is_sorted(members.iter().map(Value::as_str));
+        members.push(&display_path);
+        if was_sorted {
+            members.sort_by(|lhs, rhs| lhs.as_str().cmp(&rhs.as_str()));
+        }
+    } else {
+        let mut array = Array::new();
+        array.push(&display_path);
+
+        workspace_document["workspace"]["members"] = toml_edit::value(array);
+    }
+
+    write_atomic(
+        &root_manifest_path,
+        workspace_document.to_string().to_string().as_bytes(),
+    )
+}

tests/testsuite/cargo_init/mod.rs

@@ -42,3 +42,4 @@ mod simple_hg_ignore_exists;
 mod simple_lib;
 mod unknown_flags;
 mod with_argument;
+mod workspace_add_member;

tests/testsuite/cargo_init/workspace_add_member/in/Cargo.toml

@@ -0,0 +1,2 @@
+[workspace]
+resolver = "2"

tests/testsuite/cargo_init/empty_dir/.keep renamed to tests/testsuite/cargo_init/workspace_add_member/in/crates/foo/.keep

@@ -0,0 +1,21 @@
+use cargo_test_support::compare::assert_ui;
+use cargo_test_support::prelude::*;
+use cargo_test_support::Project;
+
+use cargo_test_support::curr_dir;
+
+#[cargo_test]
+fn case() {
+    let project = Project::from_template(curr_dir!().join("in"));
+    let project_root = &project.root();
+
+    snapbox::cmd::Command::cargo_ui()
+        .arg_line("init --bin --vcs none")
+        .current_dir(project_root.join("crates").join("foo"))
+        .assert()
+        .success()
+        .stdout_matches_path(curr_dir!().join("stdout.log"))
+        .stderr_matches_path(curr_dir!().join("stderr.log"));
+
+    assert_ui().subset_matches(curr_dir!().join("out"), &project_root);
+}

tests/testsuite/cargo_init/workspace_add_member/mod.rs

@@ -0,0 +1,3 @@
+[workspace]
+resolver = "2"
+members = ["crates/foo"]

tests/testsuite/cargo_init/workspace_add_member/out/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "foo"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

tests/testsuite/cargo_init/workspace_add_member/out/crates/foo/Cargo.toml

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

tests/testsuite/cargo_init/workspace_add_member/out/crates/foo/src/main.rs

@@ -0,0 +1 @@
+     Created binary (application) package