Auto merge of #8062 - ehuss:tree, r=alexcrichton

Add `cargo tree` command.

This migrates [cargo-tree](https://github.com/sfackler/cargo-tree/) into Cargo as a built-in command. This is based on a recent master (https://github.com/sfackler/cargo-tree/tree/4108d216ec072d2e7c9befb4de32175f97a9dbc4), and should be mostly similar in functionality. There are a variety changes:

* `--all-targets` renamed to `--no-filter-targets` to avoid confusion with the `--all-targets` flag used in other Cargo commands with a different meaning.
* `--all`/`-a` renamed to `--no-dedupe` to avoid confusion with the `-all` flag which means "all workspace crates" in other Cargo commands.
* `--duplicate` renamed to `--duplicates` (with alias), just a personal preference.
* Added support for multiple roots (workspace support).
* Added the `--graph-features` flag for including features in the graph (to "explain" why a feature is enabled).
* Added `{f}` to format string to show features.
* Handles new feature resolver.
* Handles cyclical dev dependencies.
* Added a test suite.
* Dropped the dependency on petgraph, in favor of a simpler custom graph.

Closes #7286.

src/bin/cargo/commands/mod.rs

@@ -27,6 +27,7 @@ pub fn builtin() -> Vec<App> {
         rustdoc::cli(),
         search::cli(),
         test::cli(),
+        tree::cli(),
         uninstall::cli(),
         update::cli(),
         vendor::cli(),
@@ -63,6 +64,7 @@ pub fn builtin_exec(cmd: &str) -> Option<fn(&mut Config, &ArgMatches<'_>) -> Cli
         "rustdoc" => rustdoc::exec,
         "search" => search::exec,
         "test" => test::exec,
+        "tree" => tree::exec,
         "uninstall" => uninstall::exec,
         "update" => update::exec,
         "vendor" => vendor::exec,
@@ -99,6 +101,7 @@ pub mod rustc;
 pub mod rustdoc;
 pub mod search;
 pub mod test;
+pub mod tree;
 pub mod uninstall;
 pub mod update;
 pub mod vendor;

src/bin/cargo/commands/tree.rs

@@ -0,0 +1,254 @@
+use crate::command_prelude::*;
+use anyhow::{bail, format_err};
+use cargo::core::dependency::DepKind;
+use cargo::ops::tree::{self, EdgeKind};
+use cargo::ops::Packages;
+use cargo::util::CargoResult;
+use std::collections::HashSet;
+use std::str::FromStr;
+
+pub fn cli() -> App {
+    subcommand("tree")
+        .about("Display a tree visualization of a dependency graph")
+        .arg(opt("quiet", "Suppress status messages").short("q"))
+        .arg_manifest_path()
+        .arg_package_spec_no_all(
+            "Package to be used as the root of the tree",
+            "Display the tree for all packages in the workspace",
+            "Exclude specific workspace members",
+        )
+        .arg(Arg::with_name("all").long("all").short("a").hidden(true))
+        .arg(
+            Arg::with_name("all-targets")
+                .long("all-targets")
+                .hidden(true),
+        )
+        .arg_features()
+        .arg_target_triple(
+            "Filter dependencies matching the given target-triple (default host platform)",
+        )
+        .arg(
+            Arg::with_name("no-dev-dependencies")
+                .long("no-dev-dependencies")
+                .hidden(true),
+        )
+        .arg(
+            multi_opt(
+                "edges",
+                "KINDS",
+                "The kinds of dependencies to display \
+                 (features, normal, build, dev, all, no-dev, no-build, no-normal)",
+            )
+            .short("e"),
+        )
+        .arg(
+            optional_multi_opt(
+                "invert",
+                "SPEC",
+                "Invert the tree direction and focus on the given package",
+            )
+            .short("i"),
+        )
+        .arg(Arg::with_name("no-indent").long("no-indent").hidden(true))
+        .arg(
+            Arg::with_name("prefix-depth")
+                .long("prefix-depth")
+                .hidden(true),
+        )
+        .arg(
+            opt(
+                "prefix",
+                "Change the prefix (indentation) of how each entry is displayed",
+            )
+            .value_name("PREFIX")
+            .possible_values(&["depth", "indent", "none"])
+            .default_value("indent"),
+        )
+        .arg(opt(
+            "no-dedupe",
+            "Do not de-duplicate (repeats all shared dependencies)",
+        ))
+        .arg(
+            opt(
+                "duplicates",
+                "Show only dependencies which come in multiple versions (implies -i)",
+            )
+            .short("d")
+            .alias("duplicate"),
+        )
+        .arg(
+            opt("charset", "Character set to use in output: utf8, ascii")
+                .value_name("CHARSET")
+                .possible_values(&["utf8", "ascii"])
+                .default_value("utf8"),
+        )
+        .arg(
+            opt("format", "Format string used for printing dependencies")
+                .value_name("FORMAT")
+                .short("f")
+                .default_value("{p}"),
+        )
+}
+
+pub fn exec(config: &mut Config, args: &ArgMatches<'_>) -> CliResult {
+    let prefix = if args.is_present("no-indent") {
+        config
+            .shell()
+            .warn("the --no-indent flag has been changed to --prefix=none")?;
+        "none"
+    } else if args.is_present("prefix-depth") {
+        config
+            .shell()
+            .warn("the --prefix-depth flag has been changed to --prefix=depth")?;
+        "depth"
+    } else {
+        args.value_of("prefix").unwrap()
+    };
+    let prefix = tree::Prefix::from_str(prefix).map_err(|e| anyhow::anyhow!("{}", e))?;
+
+    if args.is_present("all") {
+        return Err(format_err!(
+            "The `cargo tree` --all flag has been changed to --no-dedupe.\n\
+            If you are looking to display all workspace members, use the --workspace flag."
+        )
+        .into());
+    }
+
+    let target = if args.is_present("all-targets") {
+        config
+            .shell()
+            .warn("the --all-targets flag has been changed to --target=all")?;
+        Some("all")
+    } else {
+        args.value_of("target")
+    };
+    let target = tree::Target::from_cli(target);
+
+    let edge_kinds = parse_edge_kinds(config, args)?;
+    let graph_features = edge_kinds.contains(&EdgeKind::Feature);
+
+    let packages = args.packages_from_flags()?;
+    let mut invert = args
+        .values_of("invert")
+        .map_or_else(|| Vec::new(), |is| is.map(|s| s.to_string()).collect());
+    if args.is_present_with_zero_values("invert") {
+        match &packages {
+            Packages::Packages(ps) => {
+                // Backwards compatibility with old syntax of `cargo tree -i -p foo`.
+                invert.extend(ps.clone());
+            }
+            _ => {
+                return Err(format_err!(
+                    "The `-i` flag requires a package name.\n\
+\n\
+The `-i` flag is used to inspect the reverse dependencies of a specific\n\
+package. It will invert the tree and display the packages that depend on the\n\
+given package.\n\
+\n\
+Note that in a workspace, by default it will only display the package's\n\
+reverse dependencies inside the tree of the workspace member in the current\n\
+directory. The --workspace flag can be used to extend it so that it will show\n\
+the package's reverse dependencies across the entire workspace. The -p flag\n\
+can be used to display the package's reverse dependencies only with the\n\
+subtree of the package given to -p.\n\
+"
+                )
+                .into());
+            }
+        }
+    }
+
+    let ws = args.workspace(config)?;
+    let charset = tree::Charset::from_str(args.value_of("charset").unwrap())
+        .map_err(|e| anyhow::anyhow!("{}", e))?;
+    let opts = tree::TreeOptions {
+        features: values(args, "features"),
+        all_features: args.is_present("all-features"),
+        no_default_features: args.is_present("no-default-features"),
+        packages,
+        target,
+        edge_kinds,
+        invert,
+        prefix,
+        no_dedupe: args.is_present("no-dedupe"),
+        duplicates: args.is_present("duplicates"),
+        charset,
+        format: args.value_of("format").unwrap().to_string(),
+        graph_features,
+    };
+
+    tree::build_and_print(&ws, &opts)?;
+    Ok(())
+}
+
+fn parse_edge_kinds(config: &Config, args: &ArgMatches<'_>) -> CargoResult<HashSet<EdgeKind>> {
+    let mut kinds: Vec<&str> = args
+        .values_of("edges")
+        .map_or_else(|| Vec::new(), |es| es.flat_map(|e| e.split(',')).collect());
+    if args.is_present("no-dev-dependencies") {
+        config
+            .shell()
+            .warn("the --no-dev-dependencies flag has changed to -e=no-dev")?;
+        kinds.push("no-dev");
+    }
+    if kinds.len() == 0 {
+        kinds.extend(&["normal", "build", "dev"]);
+    }
+
+    let mut result = HashSet::new();
+    let insert_defaults = |result: &mut HashSet<EdgeKind>| {
+        result.insert(EdgeKind::Dep(DepKind::Normal));
+        result.insert(EdgeKind::Dep(DepKind::Build));
+        result.insert(EdgeKind::Dep(DepKind::Development));
+    };
+    let unknown = |k| {
+        bail!(
+            "unknown edge kind `{}`, valid values are \
+                \"normal\", \"build\", \"dev\", \
+                \"no-normal\", \"no-build\", \"no-dev\", \
+                \"features\", or \"all\"",
+            k
+        )
+    };
+    if kinds.iter().any(|k| k.starts_with("no-")) {
+        insert_defaults(&mut result);
+        for kind in &kinds {
+            match *kind {
+                "no-normal" => result.remove(&EdgeKind::Dep(DepKind::Normal)),
+                "no-build" => result.remove(&EdgeKind::Dep(DepKind::Build)),
+                "no-dev" => result.remove(&EdgeKind::Dep(DepKind::Development)),
+                "features" => result.insert(EdgeKind::Feature),
+                "normal" | "build" | "dev" | "all" => {
+                    bail!("`no-` dependency kinds cannot be mixed with other dependency kinds")
+                }
+                k => return unknown(k),
+            };
+        }
+        return Ok(result);
+    }
+    for kind in &kinds {
+        match *kind {
+            "all" => {
+                insert_defaults(&mut result);
+                result.insert(EdgeKind::Feature);
+            }
+            "features" => {
+                result.insert(EdgeKind::Feature);
+            }
+            "normal" => {
+                result.insert(EdgeKind::Dep(DepKind::Normal));
+            }
+            "build" => {
+                result.insert(EdgeKind::Dep(DepKind::Build));
+            }
+            "dev" => {
+                result.insert(EdgeKind::Dep(DepKind::Development));
+            }
+            k => return unknown(k),
+        }
+    }
+    if kinds.len() == 1 && kinds[0] == "features" {
+        insert_defaults(&mut result);
+    }
+    Ok(result)
+}

src/cargo/core/compiler/build_config.rs

@@ -1,4 +1,4 @@
-use crate::core::compiler::{CompileKind, CompileTarget};
+use crate::core::compiler::CompileKind;
 use crate::core::interning::InternedString;
 use crate::util::ProcessBuilder;
 use crate::util::{CargoResult, Config, RustfixDiagnosticServer};
@@ -45,22 +45,8 @@ impl BuildConfig {
         mode: CompileMode,
     ) -> CargoResult<BuildConfig> {
         let cfg = config.build_config()?;
-        let requested_kind = match requested_target {
-            Some(s) => CompileKind::Target(CompileTarget::new(s)?),
-            None => match &cfg.target {
-                Some(val) => {
-                    let value = if val.raw_value().ends_with(".json") {
-                        let path = val.clone().resolve_path(config);
-                        path.to_str().expect("must be utf-8 in toml").to_string()
-                    } else {
-                        val.raw_value().to_string()
-                    };
-                    CompileKind::Target(CompileTarget::new(&value)?)
-                }
-                None => CompileKind::Host,
-            },
-        };
-
+        let requested_kind =
+            CompileKind::from_requested_target(config, requested_target.as_deref())?;
         if jobs == Some(0) {
             anyhow::bail!("jobs must be at least 1")
         }

src/cargo/core/compiler/compile_kind.rs

@@ -1,5 +1,6 @@
 use crate::core::{InternedString, Target};
 use crate::util::errors::{CargoResult, CargoResultExt};
+use crate::util::Config;
 use serde::Serialize;
 use std::path::Path;
 
@@ -39,6 +40,32 @@ impl CompileKind {
             CompileKind::Target(n) => CompileKind::Target(n),
         }
     }
+
+    /// Creates a new `CompileKind` based on the requested target.
+    ///
+    /// If no target is given, this consults the config if the default is set.
+    /// Otherwise returns `CompileKind::Host`.
+    pub fn from_requested_target(
+        config: &Config,
+        target: Option<&str>,
+    ) -> CargoResult<CompileKind> {
+        let kind = match target {
+            Some(s) => CompileKind::Target(CompileTarget::new(s)?),
+            None => match &config.build_config()?.target {
+                Some(val) => {
+                    let value = if val.raw_value().ends_with(".json") {
+                        let path = val.clone().resolve_path(config);
+                        path.to_str().expect("must be utf-8 in toml").to_string()
+                    } else {
+                        val.raw_value().to_string()
+                    };
+                    CompileKind::Target(CompileTarget::new(&value)?)
+                }
+                None => CompileKind::Host,
+            },
+        };
+        Ok(kind)
+    }
 }
 
 impl serde::ser::Serialize for CompileKind {

src/cargo/core/profiles.rs

@@ -998,11 +998,7 @@ impl UnitFor {
     }
 
     pub(crate) fn map_to_features_for(&self) -> FeaturesFor {
-        if self.is_for_host_features() {
-            FeaturesFor::HostDep
-        } else {
-            FeaturesFor::NormalOrDev
-        }
+        FeaturesFor::from_for_host(self.is_for_host_features())
     }
 }
 

src/cargo/core/resolver/features.rs

@@ -92,13 +92,23 @@ pub enum HasDevUnits {
 }
 
 /// Flag to indicate if features are requested for a build dependency or not.
-#[derive(Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
 pub enum FeaturesFor {
     NormalOrDev,
     /// Build dependency or proc-macro.
     HostDep,
 }
 
+impl FeaturesFor {
+    pub fn from_for_host(for_host: bool) -> FeaturesFor {
+        if for_host {
+            FeaturesFor::HostDep
+        } else {
+            FeaturesFor::NormalOrDev
+        }
+    }
+}
+
 impl FeatureOpts {
     fn new(config: &Config, has_dev_units: HasDevUnits) -> CargoResult<FeatureOpts> {
         let mut opts = FeatureOpts::default();

src/cargo/core/resolver/resolve.rs

@@ -305,6 +305,10 @@ unable to verify that `{0}` is the same as when the lockfile was generated
         PackageIdSpec::query_str(spec, self.iter())
     }
 
+    pub fn specs_to_ids(&self, specs: &[PackageIdSpec]) -> CargoResult<Vec<PackageId>> {
+        specs.iter().map(|s| s.query(self.iter())).collect()
+    }
+
     pub fn unused_patches(&self) -> &[PackageId] {
         &self.unused_patches
     }