From c3f4b0db2d96d080f2523d8ee5556468075b2b4c Mon Sep 17 00:00:00 2001
From: Eric Huss <eric@huss.org>
Date: Wed, 9 Jan 2019 21:04:16 -0800
Subject: [PATCH] cargo metadata: Don't show `null` deps.

If a package has a dependency without a library target, the "name" field was
showing up as null in `resolve.nodes.deps`. At this time (AFAIK), binary-only
dependencies are always ignored. Instead of making users filter out this entry
(or more commonly, crash), just don't include it.
---
 src/cargo/ops/cargo_output_metadata.rs    | 11 ++++-----
 src/doc/man/cargo-metadata.adoc           |  2 +-
 src/doc/man/generated/cargo-metadata.html |  2 +-
 src/etc/man/cargo-metadata.1              |  2 +-
 tests/testsuite/metadata.rs               | 29 +++++++++++++++++++++++
 5 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/src/cargo/ops/cargo_output_metadata.rs b/src/cargo/ops/cargo_output_metadata.rs
index 0b05f667867..b3fed981a35 100644
--- a/src/cargo/ops/cargo_output_metadata.rs
+++ b/src/cargo/ops/cargo_output_metadata.rs
@@ -105,7 +105,7 @@ where
 {
     #[derive(Serialize)]
     struct Dep {
-        name: Option<String>,
+        name: String,
         pkg: PackageId,
     }
 
@@ -123,13 +123,12 @@ where
             dependencies: resolve.deps(id).map(|(pkg, _deps)| pkg).collect(),
             deps: resolve
                 .deps(id)
-                .map(|(pkg, _deps)| {
-                    let name = packages
+                .filter_map(|(pkg, _deps)| {
+                    packages
                         .get(&pkg)
                         .and_then(|pkg| pkg.targets().iter().find(|t| t.is_lib()))
-                        .and_then(|lib_target| resolve.extern_crate_name(id, pkg, lib_target).ok());
-
-                    Dep { name, pkg }
+                        .and_then(|lib_target| resolve.extern_crate_name(id, pkg, lib_target).ok())
+                        .map(|name| Dep { name, pkg })
                 })
                 .collect(),
             features: resolve.features_sorted(id),
diff --git a/src/doc/man/cargo-metadata.adoc b/src/doc/man/cargo-metadata.adoc
index 35e6926a834..760c8d4a9a9 100644
--- a/src/doc/man/cargo-metadata.adoc
+++ b/src/doc/man/cargo-metadata.adoc
@@ -212,7 +212,7 @@ The output has the following format:
                 */
                 "deps": [
                     {
-                        /* The name of the dependency.
+                        /* The name of the dependency's library target.
                            If this is a renamed dependency, this is the new
                            name.
                         */
diff --git a/src/doc/man/generated/cargo-metadata.html b/src/doc/man/generated/cargo-metadata.html
index 271a8ea97ec..822e8d355fe 100644
--- a/src/doc/man/generated/cargo-metadata.html
+++ b/src/doc/man/generated/cargo-metadata.html
@@ -219,7 +219,7 @@ <h2 id="cargo_metadata_output_format">OUTPUT FORMAT</h2>
                 */
                 "deps": [
                     {
-                        /* The name of the dependency.
+                        /* The name of the dependency's library target.
                            If this is a renamed dependency, this is the new
                            name.
                         */
diff --git a/src/etc/man/cargo-metadata.1 b/src/etc/man/cargo-metadata.1
index b646ef7b25b..b639bc3bc04 100644
--- a/src/etc/man/cargo-metadata.1
+++ b/src/etc/man/cargo-metadata.1
@@ -233,7 +233,7 @@ The output has the following format:
                 */
                 "deps": [
                     {
-                        /* The name of the dependency.
+                        /* The name of the dependency\(aqs library target.
                            If this is a renamed dependency, this is the new
                            name.
                         */
diff --git a/tests/testsuite/metadata.rs b/tests/testsuite/metadata.rs
index 7c5a2bf4ed5..33b3022200d 100644
--- a/tests/testsuite/metadata.rs
+++ b/tests/testsuite/metadata.rs
@@ -1669,3 +1669,32 @@ fn metadata_links() {
         )
         .run()
 }
+
+#[test]
+fn deps_with_bin_only() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "0.1.0"
+            [dependencies]
+            bdep = { path = "bdep" }
+        "#,
+        )
+        .file("src/lib.rs", "")
+        .file("bdep/Cargo.toml", &basic_bin_manifest("bdep"))
+        .file("bdep/src/main.rs", "fn main() {}")
+        .build();
+
+    let output = p
+        .cargo("metadata")
+        .exec_with_output()
+        .expect("cargo metadata failed");
+    let stdout = std::str::from_utf8(&output.stdout).unwrap();
+    let meta: serde_json::Value = serde_json::from_str(stdout).expect("failed to parse json");
+    let nodes = &meta["resolve"]["nodes"];
+    assert!(nodes[0]["deps"].as_array().unwrap().is_empty());
+    assert!(nodes[1]["deps"].as_array().unwrap().is_empty());
+}