make cargo install ignore .cargo/config

closes #5850

src/bin/cargo/commands/install.rs

@@ -74,7 +74,7 @@ continuous integration systems.",
 }
 
 pub fn exec(config: &mut Config, args: &ArgMatches) -> CliResult {
-    let mut compile_opts = args.compile_options(config, CompileMode::Build)?;
+    let mut compile_opts = args.compile_options(config, CompileMode::Install)?;
     compile_opts.build_config.release = !args.is_present("debug");
 
     let krates = args.values_of("crate")

src/cargo/core/compiler/build_config.rs

@@ -60,8 +60,13 @@ impl BuildConfig {
                 bail!("target was empty")
             }
         }
+        let target = if mode == CompileMode::Install {
+            // ignore `.cargo/config` when compiling for `cargo install`
+            requested_target
+        } else {
             let cfg_target = config.get_string("build.target")?.map(|s| s.val);
-        let target = requested_target.clone().or(cfg_target);
+            requested_target.clone().or(cfg_target)
+        };
 
         if jobs == Some(0) {
             bail!("jobs must be at least 1")
@@ -131,6 +136,8 @@ pub enum CompileMode {
     Doc { deps: bool },
     /// A target that will be tested with `rustdoc`.
     Doctest,
+    // Like `Build` but we are compiling something that will be installed
+    Install,
     /// A marker for Units that represent the execution of a `build.rs`
     /// script.
     RunCustomBuild,

src/cargo/core/profiles.rs

@@ -84,6 +84,7 @@ impl Profiles {
             CompileMode::Build
             | CompileMode::Check { .. }
             | CompileMode::Doctest
+            | CompileMode::Install
             | CompileMode::RunCustomBuild => {
                 // Note: RunCustomBuild doesn't normally use this code path.
                 // `build_unit_profiles` normally ensures that it selects the

src/cargo/ops/cargo_compile.rs

@@ -386,7 +386,10 @@ impl CompileFilter {
     pub fn need_dev_deps(&self, mode: CompileMode) -> bool {
         match mode {
             CompileMode::Test | CompileMode::Doctest | CompileMode::Bench => true,
-            CompileMode::Build | CompileMode::Doc { .. } | CompileMode::Check { .. } => match *self
+            CompileMode::Build
+            | CompileMode::Doc { .. }
+            | CompileMode::Check { .. }
+            | CompileMode::Install => match *self
             {
                 CompileFilter::Default { .. } => false,
                 CompileFilter::Only {
@@ -707,7 +710,7 @@ fn filter_default_targets(targets: &[Target], mode: CompileMode) -> Vec<&Target>
             .iter()
             .filter(|t| t.tested() || t.is_example())
             .collect(),
-        CompileMode::Build | CompileMode::Check { .. } => targets
+        CompileMode::Build | CompileMode::Check { .. } | CompileMode::Install => targets
             .iter()
             .filter(|t| t.is_bin() || t.is_lib())
             .collect(),

tests/testsuite/install.rs

@@ -1237,3 +1237,33 @@ warning: be sure to add `[..]` to your PATH to be able to run the installed bina
 ",
         ).run();
 }
+
+fn install_ignores_cargo_config() {
+    pkg("bar", "0.0.1");
+
+    let p = project("foo")
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "0.1.0"
+            authors = []
+        "#,
+        )
+        .file(
+            ".cargo/config",
+            r#"
+            [build]
+            target = "non-existing-target"
+        "#,
+        )
+        .file("src/main.rs", "fn main() {}")
+        .build();
+
+    assert_that(
+        cargo_process("install").arg("bar").cwd(p.root()),
+        execs().with_status(0),
+    );
+    assert_that(cargo_home(), has_installed_exe("bar"));
+}