Warn for resolver = "2" and edition = "2015"

CHANGELOG.md

@@ -30,6 +30,18 @@
     warning: `--toolchain` was renamed to `--toolchain-for-udeps`
     ```
 
+- cargo-equip now warns for `resolver = "2"` and `edition = "2015"`.
+
+    Note that both has been unsupported.
+
+    ```console
+    warning: Currently cargo-equip only support Feature Resovler v1, and may go search more crates than real Cargo does. Please watch https://github.com/qryxip/cargo-equip/issues/94
+    ```
+
+    ```console
+    warning: Rust 2015 is unsupported
+    ```
+
 ### Fixed
 
 - Updated [prettytable](https://docs.rs/crate/prettytable). ([#193](https://github.com/qryxip/cargo-equip/pull/193) by [@ichyo](https://github.com/ichyo))

Cargo.toml

@@ -37,10 +37,12 @@ serde = { version = "1.0.181", features = ["derive"] }
 serde_json = "1.0.104"
 spdx = "0.6.2"
 structopt = "0.3.26"
+strum = { version = "0.25.0", features = ["derive"] }
 syn = { version = "1.0.109", features = ["extra-traits", "full", "parsing", "visit"] }
 tap = "1.0.1"
 tempfile = "3.7.0"
 termcolor = "1.2.0"
+toml = "0.7.6"
 toml_edit = "0.5.0"
 which = "4.4.0"
 

src/lib.rs

@@ -15,7 +15,10 @@ use crate::{
     ra_proc_macro::ProcMacroExpander,
     rust::CodeEdit,
     shell::Shell,
-    workspace::{MetadataExt as _, PackageExt as _, PackageIdExt as _, TargetExt as _},
+    workspace::{
+        Edition, MetadataExt as _, PackageExt as _, PackageIdExt as _, ResolveBehavior,
+        TargetExt as _,
+    },
 };
 use anyhow::Context as _;
 use cargo_metadata as cm;
@@ -500,6 +503,17 @@ pub fn run(opt: Opt, ctx: Context<'_>) -> anyhow::Result<()> {
         metadata.exactly_one_target()
     }?;
 
+    if root_package.edition() == Edition::Edition2015 {
+        shell.warn("Rust 2015 is unsupported")?;
+    }
+    let resolve_behavior = workspace::resolve_behavior(root_package, &metadata.workspace_root)?;
+    if resolve_behavior >= ResolveBehavior::V2 {
+        shell.warn(
+            "Currently cargo-equip only support Feature Resovler v1, and may go search more crates \
+             than real Cargo does. Please watch https://github.com/qryxip/cargo-equip/issues/94",
+        )?;
+    }
+
     let libs_to_bundle = {
         let unused_deps = &if root.is_lib() {
             hashset!()

src/workspace.rs

@@ -10,13 +10,15 @@ use indoc::indoc;
 use itertools::Itertools as _;
 use krates::PkgSpec;
 use rand::Rng as _;
+use serde::Deserialize;
 use std::{
     collections::{BTreeMap, HashMap, HashSet},
     env,
     io::Cursor,
     path::{Path, PathBuf},
     str,
 };
+use strum::EnumString;
 
 pub(crate) fn locate_project(cwd: &Path) -> anyhow::Result<PathBuf> {
     cwd.ancestors()
@@ -37,6 +39,28 @@ pub(crate) fn cargo_metadata(manifest_path: &Path, cwd: &Path) -> cm::Result<cm:
         .exec()
 }
 
+pub(crate) fn resolve_behavior(
+    package: &cm::Package,
+    workspace_root: &Utf8Path,
+) -> anyhow::Result<ResolveBehavior> {
+    let cargo_toml = &cargo_util::paths::read(workspace_root.join("Cargo.toml").as_ref())?;
+    let CargoToml { workspace } = toml::from_str(cargo_toml)?;
+    return Ok(workspace
+        .resolver
+        .unwrap_or_else(|| package.edition().default_resolver_behavior()));
+
+    #[derive(Deserialize)]
+    struct CargoToml {
+        #[serde(default)]
+        workspace: Workspace,
+    }
+
+    #[derive(Default, Deserialize)]
+    struct Workspace {
+        resolver: Option<ResolveBehavior>,
+    }
+}
+
 pub(crate) fn cargo_check_message_format_json(
     toolchain: &str,
     metadata: &cm::Metadata,
@@ -640,6 +664,7 @@ pub(crate) trait PackageExt {
     fn has_proc_macro(&self) -> bool;
     fn lib_like_target(&self) -> Option<&cm::Target>;
     fn manifest_dir(&self) -> &Utf8Path;
+    fn edition(&self) -> Edition;
     fn read_license_text(&self, mine: &[User], cache_dir: &Path) -> anyhow::Result<Option<String>>;
 }
 
@@ -666,6 +691,10 @@ impl PackageExt for cm::Package {
         self.manifest_path.parent().expect("should not be empty")
     }
 
+    fn edition(&self) -> Edition {
+        self.edition.parse().expect("`edition` modified invalidly")
+    }
+
     fn read_license_text(&self, mine: &[User], cache_dir: &Path) -> anyhow::Result<Option<String>> {
         license::read_non_unlicense_license_file(self, mine, cache_dir)
     }
@@ -752,3 +781,30 @@ impl SourceExt for cm::Source {
         }
     }
 }
+
+#[derive(Clone, Copy, PartialEq, EnumString)]
+pub(crate) enum Edition {
+    #[strum(serialize = "2015")]
+    Edition2015,
+    #[strum(serialize = "2018")]
+    Edition2018,
+    #[strum(serialize = "2021")]
+    Edition2021,
+}
+
+impl Edition {
+    fn default_resolver_behavior(self) -> ResolveBehavior {
+        match self {
+            Self::Edition2015 | Self::Edition2018 => ResolveBehavior::V1,
+            Self::Edition2021 => ResolveBehavior::V2,
+        }
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, PartialOrd, Deserialize)]
+pub(crate) enum ResolveBehavior {
+    #[serde(rename = "1")]
+    V1,
+    #[serde(rename = "2")]
+    V2,
+}