Auto merge of #5604 - debris:issue_5602, r=matklad

fixed 5602, expose cached build script output in json output

fixes #5602

Author: bors

src/cargo/core/compiler/custom_build.rs

@@ -105,6 +105,22 @@ pub fn prepare<'a, 'cfg>(
     }
 }
 
+fn emit_build_output(output: &BuildOutput, id: &PackageId) {
+    let library_paths = output
+        .library_paths
+        .iter()
+        .map(|l| l.display().to_string())
+        .collect::<Vec<_>>();
+
+    machine_message::emit(&machine_message::BuildScript {
+        package_id: id,
+        linked_libs: &output.library_links,
+        linked_paths: &library_paths,
+        cfgs: &output.cfgs,
+        env: &output.env,
+    });
+}
+
 fn build_work<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoResult<(Work, Work)> {
     assert!(unit.mode.is_run_custom_build());
     let bcx = &cx.bcx;
@@ -336,18 +352,7 @@ fn build_work<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoRes
                 BuildOutput::parse(&output.stdout, &pkg_name, &root_output, &root_output)?;
 
             if json_messages {
-                let library_paths = parsed_output
-                    .library_paths
-                    .iter()
-                    .map(|l| l.display().to_string())
-                    .collect::<Vec<_>>();
-                machine_message::emit(&machine_message::BuildScript {
-                    package_id: &id,
-                    linked_libs: &parsed_output.library_links,
-                    linked_paths: &library_paths,
-                    cfgs: &parsed_output.cfgs,
-                    env: &parsed_output.env,
-                });
+                emit_build_output(&parsed_output, &id);
             }
             build_state.insert(id, kind, parsed_output);
         }
@@ -365,6 +370,11 @@ fn build_work<'a, 'cfg>(cx: &mut Context<'a, 'cfg>, unit: &Unit<'a>) -> CargoRes
                 BuildOutput::parse_file(&output_file, &pkg_name, &prev_root_output, &root_output)?
             }
         };
+
+        if json_messages {
+            emit_build_output(&output, &id);
+        }
+
         build_state.insert(id, kind, output);
         Ok(())
     });

tests/testsuite/build.rs

@@ -3981,6 +3981,7 @@ fn compiler_json_error_format() {
             path = "bar"
         "#,
         )
+        .file("build.rs", "fn main() { println!(\"cargo:rustc-cfg=xyz\") }")
         .file("src/main.rs", "fn main() { let unused = 92; }")
         .file(
             "bar/Cargo.toml",
@@ -4035,6 +4036,36 @@ fn compiler_json_error_format() {
         "fresh": false
     }
 
+    {
+        "reason":"compiler-artifact",
+        "package_id":"foo 0.5.0 ([..])",
+        "target":{
+            "kind":["custom-build"],
+            "crate_types":["bin"],
+            "name":"build-script-build",
+            "src_path":"[..]build.rs"
+        },
+        "profile": {
+            "debug_assertions": true,
+            "debuginfo": 2,
+            "opt_level": "0",
+            "overflow_checks": true,
+            "test": false
+        },
+        "features": [],
+        "filenames": "{...}",
+        "fresh": false
+    }
+
+    {
+        "reason":"build-script-executed",
+        "package_id":"foo 0.5.0 ([..])",
+        "linked_libs":[],
+        "linked_paths":[],
+        "env":[],
+        "cfgs":["xyz"]
+    }
+
     {
         "reason":"compiler-message",
         "package_id":"foo 0.5.0 ([..])",
@@ -4080,6 +4111,27 @@ fn compiler_json_error_format() {
             .arg("json"),
         execs().with_status(0).with_json(
             r#"
+    {
+        "reason":"compiler-artifact",
+        "package_id":"foo 0.5.0 ([..])",
+        "target":{
+            "kind":["custom-build"],
+            "crate_types":["bin"],
+            "name":"build-script-build",
+            "src_path":"[..]build.rs"
+        },
+        "profile": {
+            "debug_assertions": true,
+            "debuginfo": 2,
+            "opt_level": "0",
+            "overflow_checks": true,
+            "test": false
+        },
+        "features": [],
+        "filenames": "{...}",
+        "fresh": true
+    }
+
     {
         "reason":"compiler-artifact",
         "profile": {
@@ -4101,6 +4153,15 @@ fn compiler_json_error_format() {
         "fresh": true
     }
 
+    {
+        "reason":"build-script-executed",
+        "package_id":"foo 0.5.0 ([..])",
+        "linked_libs":[],
+        "linked_paths":[],
+        "env":[],
+        "cfgs":["xyz"]
+    }
+
     {
         "reason":"compiler-artifact",
         "package_id":"foo 0.5.0 ([..])",