Add format option to cargo tree to print the package version constraint

- Add a new formatting option {c} to `cargo tree` that prints the resolved
version constraint of packages as specified in Cargo.toml.
- Add a unit test to verify that the version constraint is printed correctly.
- Update the `cargo tree` command documentation with the new option.

Author: devodev

src/cargo/ops/tree/format/mod.rs

@@ -14,6 +14,7 @@ enum Chunk {
     Repository,
     Features,
     LibName,
+    Constraint,
 }
 
 pub struct Pattern(Vec<Chunk>);
@@ -30,6 +31,7 @@ impl Pattern {
                 RawChunk::Argument("r") => Chunk::Repository,
                 RawChunk::Argument("f") => Chunk::Features,
                 RawChunk::Argument("lib") => Chunk::LibName,
+                RawChunk::Argument("c") => Chunk::Constraint,
                 RawChunk::Argument(a) => {
                     bail!("unsupported pattern `{}`", a);
                 }
@@ -63,6 +65,7 @@ impl<'a> fmt::Display for Display<'a> {
             Node::Package {
                 package_id,
                 features,
+                version_req,
                 ..
             } => {
                 let package = self.graph.package_for_id(*package_id);
@@ -111,6 +114,9 @@ impl<'a> fmt::Display for Display<'a> {
                                 write!(fmt, "{}", target.crate_name())?;
                             }
                         }
+                        Chunk::Constraint => {
+                            write!(fmt, "{}", version_req)?;
+                        }
                     }
                 }
             }

src/cargo/ops/tree/graph.rs

@@ -6,8 +6,8 @@ use crate::core::dependency::DepKind;
 use crate::core::resolver::Resolve;
 use crate::core::resolver::features::{CliFeatures, FeaturesFor, ResolvedFeatures};
 use crate::core::{FeatureMap, FeatureValue, Package, PackageId, PackageIdSpec, Workspace};
-use crate::util::CargoResult;
 use crate::util::interning::{INTERNED_DEFAULT, InternedString};
+use crate::util::{CargoResult, OptVersionReq};
 use std::collections::{HashMap, HashSet};
 
 #[derive(Debug, Copy, Clone)]
@@ -56,6 +56,7 @@ pub enum Node {
         /// Features that are enabled on this package.
         features: Vec<InternedString>,
         kind: CompileKind,
+        version_req: OptVersionReq,
     },
     Feature {
         /// Index of the package node this feature is for.
@@ -332,13 +333,15 @@ impl<'a> Graph<'a> {
                             Node::Package {
                                 package_id,
                                 features,
+                                version_req,
                                 ..
                             } => {
                                 // Do not treat duplicates on the host or target as duplicates.
                                 Node::Package {
                                     package_id: package_id.clone(),
                                     features: features.clone(),
                                     kind: CompileKind::Host,
+                                    version_req: version_req.clone(),
                                 }
                             }
                             _ => unreachable!(),
@@ -376,12 +379,14 @@ pub fn build<'a>(
         let member_id = member.package_id();
         let features_for = FeaturesFor::from_for_host(member.proc_macro());
         for kind in requested_kinds {
+            let version_req = OptVersionReq::Any;
             let member_index = add_pkg(
                 &mut graph,
                 resolve,
                 resolved_features,
                 member_id,
                 features_for,
+                version_req,
                 target_data,
                 *kind,
                 opts,
@@ -409,6 +414,7 @@ fn add_pkg(
     resolved_features: &ResolvedFeatures,
     package_id: PackageId,
     features_for: FeaturesFor,
+    version_req: OptVersionReq,
     target_data: &RustcTargetData<'_>,
     requested_kind: CompileKind,
     opts: &TreeOptions,
@@ -423,6 +429,7 @@ fn add_pkg(
         package_id,
         features: node_features,
         kind: node_kind,
+        version_req: version_req,
     };
     if let Some(idx) = graph.index.get(&node) {
         return *idx;
@@ -513,12 +520,14 @@ fn add_pkg(
                     }
                 }
             };
+            let dep_version_req = dep.version_req().clone();
             let dep_index = add_pkg(
                 graph,
                 resolve,
                 resolved_features,
                 dep_id,
                 dep_features_for,
+                dep_version_req,
                 target_data,
                 requested_kind,
                 opts,

src/cargo/util/semver_ext.rs

@@ -1,6 +1,9 @@
 use super::semver_eval_ext;
 use semver::{Comparator, Op, Version, VersionReq};
-use std::fmt::{self, Display};
+use std::{
+    cmp::Ordering,
+    fmt::{self, Display},
+};
 
 pub trait VersionExt {
     fn is_prerelease(&self) -> bool;
@@ -174,6 +177,19 @@ impl OptVersionReq {
     }
 }
 
+impl PartialOrd for OptVersionReq {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+// OptVersionReq is not meaningfully orderable, so we default to considering all values equal.
+impl Ord for OptVersionReq {
+    fn cmp(&self, _: &Self) -> Ordering {
+        Ordering::Equal
+    }
+}
+
 impl Display for OptVersionReq {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {

src/doc/man/cargo-tree.md

@@ -167,6 +167,7 @@ strings will be replaced with the corresponding value:
 - `{r}` --- The package repository URL.
 - `{f}` --- Comma-separated list of package features that are enabled.
 - `{lib}` --- The name, as used in a `use` statement, of the package's library.
+- `{c}` --- The version constraint resolved for the package.
 {{/option}}
 
 {{#option "`--prefix` _prefix_" }}

src/doc/man/generated_txt/cargo-tree.txt

@@ -166,6 +166,8 @@ OPTIONS
            o  {lib} — The name, as used in a use statement, of the
               package’s library.
 
+           o  {c} — The version constraint resolved for the package.
+
        --prefix prefix
            Sets how each line is displayed. The prefix value can be one of:
 

src/doc/src/commands/cargo-tree.md

@@ -170,6 +170,7 @@ strings will be replaced with the corresponding value:</p>
 <li><code>{r}</code> — The package repository URL.</li>
 <li><code>{f}</code> — Comma-separated list of package features that are enabled.</li>
 <li><code>{lib}</code> — The name, as used in a <code>use</code> statement, of the package’s library.</li>
+<li><code>{c}</code> — The version constraint resolved for the package.</li>
 </ul>
 </dd>
 

src/etc/man/cargo-tree.1

@@ -208,6 +208,10 @@ strings will be replaced with the corresponding value:
 .RS 4
 \h'-04'\(bu\h'+03'\fB{lib}\fR \[em] The name, as used in a \fBuse\fR statement, of the package\[cq]s library.
 .RE
+.sp
+.RS 4
+\h'-04'\(bu\h'+03'\fB{c}\fR \[em] The version constraint resolved for the package.
+.RE
 .RE
 .sp
 \fB\-\-prefix\fR \fIprefix\fR