Add graphviz output to puffin-dev resolve-cli (#443)

I added output in graphviz DOT format to `puffin-dev resolve-cli` to
help with debugging resolutions. This requires tracking the requested
ranges in the graph. I also fixed the direction of the graph.

 Output for `black`:

```dot
digraph {
    0 [ label="click\n8.1.7"]
    1 [ label="black\n23.11.0"]
    2 [ label="packaging\n23.2"]
    3 [ label="mypy-extensions\n1.0.0"]
    4 [ label="tomli\n2.0.1"]
    5 [ label="pathspec\n0.11.2"]
    6 [ label="typing-extensions\n4.8.0"]
    7 [ label="platformdirs\n4.0.0"]
    1 -> 0 [ label=">=8.0.0"]
    1 -> 3 [ label=">=0.4.3"]
    1 -> 5 [ label=">=0.9.0"]
    1 -> 4 [ label=">=1.1.0"]
    1 -> 6 [ label=">=4.0.1"]
    1 -> 2 [ label=">=22.0"]
    1 -> 7 [ label=">=2"]
}
```


![image](https://github.com/astral-sh/puffin/assets/6826232/4a440fcd-6248-4349-8e1a-c3e0363e42b1)

transformers:


![image](https://github.com/astral-sh/puffin/assets/6826232/a13a693c-a8c0-4a4f-95d9-3458431c678a)

jupyter:


![graphviz](https://github.com/astral-sh/puffin/assets/6826232/ef730033-6fd9-4ea9-ac93-8c874c19a101)

Cargo.lock

@@ -2458,6 +2458,7 @@ dependencies = [
  "itertools 0.11.0",
  "mimalloc",
  "pep508_rs",
+ "petgraph",
  "platform-host",
  "platform-tags",
  "puffin-build",
@@ -2465,6 +2466,7 @@ dependencies = [
  "puffin-client",
  "puffin-dispatch",
  "puffin-interpreter",
+ "puffin-resolver",
  "puffin-traits",
  "pypi-types",
  "tempfile",

crates/puffin-dev/Cargo.toml

@@ -21,6 +21,7 @@ puffin-cache = { path = "../puffin-cache", features = ["clap"] }
 puffin-client = { path = "../puffin-client" }
 puffin-dispatch = { path = "../puffin-dispatch" }
 puffin-interpreter = { path = "../puffin-interpreter" }
+puffin-resolver = { path = "../puffin-resolver" }
 pypi-types = { path = "../pypi-types" }
 puffin-traits = { path = "../puffin-traits" }
 
@@ -32,6 +33,7 @@ fs-err = { workspace = true }
 futures = { workspace = true }
 indicatif = { workspace = true }
 itertools = { workspace = true }
+petgraph = { workspace = true }
 tempfile = { workspace = true }
 tokio = { workspace = true }
 tracing = { workspace = true }

crates/puffin-dev/src/resolve_cli.rs

@@ -1,22 +1,29 @@
 use std::fs;
+use std::io::{BufWriter, Write};
+use std::path::PathBuf;
 
 use anstream::println;
+use anyhow::Context;
 use clap::Parser;
+use fs_err::File;
 use itertools::Itertools;
+use petgraph::dot::{Config as DotConfig, Dot};
 
 use pep508_rs::Requirement;
 use platform_host::Platform;
+use platform_tags::Tags;
 use puffin_cache::{CacheArgs, CacheDir};
 use puffin_client::RegistryClientBuilder;
 use puffin_dispatch::BuildDispatch;
 use puffin_interpreter::Virtualenv;
-use puffin_traits::BuildContext;
+use puffin_resolver::{Manifest, PreReleaseMode, ResolutionMode, Resolver};
 
 #[derive(Parser)]
 pub(crate) struct ResolveCliArgs {
     requirements: Vec<Requirement>,
+    /// Write debug output in DOT format for graphviz to this file
     #[clap(long)]
-    limit: Option<usize>,
+    graphviz: Option<PathBuf>,
     /// Don't build source distributions. This means resolving will not run arbitrary code. The
     /// cached wheels of already built source distributions will be reused.
     #[clap(long)]
@@ -30,15 +37,61 @@ pub(crate) async fn resolve_cli(args: ResolveCliArgs) -> anyhow::Result<()> {
 
     let platform = Platform::current()?;
     let venv = Virtualenv::from_env(platform, Some(cache_dir.path()))?;
+    let client = RegistryClientBuilder::new(cache_dir.path().clone()).build();
     let build_dispatch = BuildDispatch::new(
-        RegistryClientBuilder::new(cache_dir.path().clone()).build(),
+        client.clone(),
         cache_dir.path().clone(),
         venv.interpreter_info().clone(),
         fs::canonicalize(venv.python_executable())?,
         args.no_build,
     );
 
-    let mut resolution = build_dispatch.resolve(&args.requirements).await?;
+    // Copied from `BuildDispatch`
+    let tags = Tags::from_env(
+        venv.interpreter_info().platform(),
+        venv.interpreter_info().simple_version(),
+    )?;
+    let resolver = Resolver::new(
+        // TODO(konstin): Split settings (for all resolutions) and inputs (only for this
+        // resolution) and attach the former to Self.
+        Manifest::new(
+            args.requirements.clone(),
+            Vec::default(),
+            Vec::default(),
+            ResolutionMode::default(),
+            PreReleaseMode::default(),
+            None, // TODO(zanieb): We may want to provide a project name here
+            None,
+        ),
+        venv.interpreter_info().markers(),
+        &tags,
+        &client,
+        &build_dispatch,
+    );
+    let resolution_graph = resolver.resolve().await.with_context(|| {
+        format!(
+            "No solution found when resolving: {}",
+            args.requirements.iter().map(ToString::to_string).join(", "),
+        )
+    })?;
+
+    if let Some(graphviz) = args.graphviz {
+        let mut writer = BufWriter::new(File::create(graphviz)?);
+        let graphviz = Dot::with_attr_getters(
+            resolution_graph.petgraph(),
+            &[DotConfig::NodeNoLabel, DotConfig::EdgeNoLabel],
+            &|_graph, edge_ref| format!("label={:?}", edge_ref.weight().to_string()),
+            &|_graph, (_node_index, dist)| {
+                format!(
+                    "label={:?}",
+                    dist.to_string().replace("==", "\n").to_string()
+                )
+            },
+        );
+        write!(&mut writer, "{graphviz:?}")?;
+    }
+
+    let mut resolution = resolution_graph.requirements();
     resolution.sort_unstable_by(|a, b| a.name.cmp(&b.name));
 
     // Concise format for dev

crates/puffin-resolver/src/resolution.rs

@@ -3,6 +3,7 @@ use std::hash::BuildHasherDefault;
 use colored::Colorize;
 use fxhash::FxHashMap;
 use petgraph::visit::EdgeRef;
+use petgraph::Direction;
 use pubgrub::range::Range;
 use pubgrub::solver::{Kind, State};
 use pubgrub::type_aliases::SelectedDependencies;
@@ -51,7 +52,7 @@ impl Resolution {
 /// A complete resolution graph in which every node represents a pinned package and every edge
 /// represents a dependency between two pinned packages.
 #[derive(Debug)]
-pub struct Graph(petgraph::graph::Graph<Dist, (), petgraph::Directed>);
+pub struct Graph(petgraph::graph::Graph<Dist, Range<PubGrubVersion>, petgraph::Directed>);
 
 impl Graph {
     /// Create a new graph from the resolved `PubGrub` state.
@@ -98,8 +99,12 @@ impl Graph {
         // Add every edge to the graph.
         for (package, version) in selection {
             for id in &state.incompatibilities[package] {
-                if let Kind::FromDependencyOf(self_package, self_version, dependency_package, _) =
+                if let Kind::FromDependencyOf(
-                    &state.incompatibility_store[*id].kind
+                    self_package,
+                    self_version,
+                    dependency_package,
+                    dependency_range,
+                ) = &state.incompatibility_store[*id].kind
                 {
                     let PubGrubPackage::Package(self_package, None, _) = self_package else {
                         continue;
@@ -112,7 +117,7 @@ impl Graph {
                     if self_version.contains(version) {
                         let self_index = &inverse[self_package];
                         let dependency_index = &inverse[dependency_package];
-                        graph.update_edge(*dependency_index, *self_index, ());
+                        graph.update_edge(*self_index, *dependency_index, dependency_range.clone());
                     }
                 }
             }
@@ -179,6 +184,13 @@ impl Graph {
             })
             .collect()
     }
+
+    /// Return the underlying graph.
+    pub fn petgraph(
+        &self,
+    ) -> &petgraph::graph::Graph<Dist, Range<PubGrubVersion>, petgraph::Directed> {
+        &self.0
+    }
 }
 
 /// Write the graph in the `{name}=={version}` format of requirements.txt that pip uses.
@@ -198,8 +210,8 @@ impl std::fmt::Display for Graph {
 
             let mut edges = self
                 .0
-                .edges(index)
+                .edges_directed(index, Direction::Incoming)
-                .map(|edge| &self.0[edge.target()])
+                .map(|edge| &self.0[edge.source()])
                 .collect::<Vec<_>>();
             edges.sort_unstable_by_key(|package| package.name());