fix(cli): Use stderr for user messages (#527)

Fixes #526

src/bin/add/main.rs

@@ -74,7 +74,7 @@ fn print_msg(dep: &Dependency, section: &[String], optional: bool) -> Result<()>
     } else {
         ColorChoice::Never
     };
-    let mut output = StandardStream::stdout(colorchoice);
+    let mut output = StandardStream::stderr(colorchoice);
     output.set_color(ColorSpec::new().set_fg(Some(Color::Green)).set_bold(true))?;
     write!(output, "{:>12}", "Adding")?;
     output.reset()?;

src/bin/rm/main.rs

@@ -94,7 +94,7 @@ fn print_msg(name: &str, section: &str) -> Result<()> {
     } else {
         ColorChoice::Never
     };
-    let mut output = StandardStream::stdout(colorchoice);
+    let mut output = StandardStream::stderr(colorchoice);
     output.set_color(ColorSpec::new().set_fg(Some(Color::Green)).set_bold(true))?;
     write!(output, "{:>12}", "Removing")?;
     output.reset()?;

src/bin/set-version/main.rs

@@ -209,7 +209,7 @@ impl Manifests {
 }
 
 fn dry_run_message() -> Result<()> {
-    let bufwtr = BufferWriter::stdout(ColorChoice::Always);
+    let bufwtr = BufferWriter::stderr(ColorChoice::Always);
     let mut buffer = bufwtr.buffer();
     buffer
         .set_color(ColorSpec::new().set_fg(Some(Color::Cyan)).set_bold(true))
@@ -241,7 +241,7 @@ fn deprecated_message(message: &str) -> Result<()> {
 }
 
 fn upgrade_message(name: &str, from: &semver::Version, to: &semver::Version) -> Result<()> {
-    let bufwtr = BufferWriter::stdout(ColorChoice::Always);
+    let bufwtr = BufferWriter::stderr(ColorChoice::Always);
     let mut buffer = bufwtr.buffer();
     buffer
         .set_color(ColorSpec::new().set_fg(Some(Color::Green)).set_bold(true))
@@ -258,7 +258,7 @@ fn upgrade_message(name: &str, from: &semver::Version, to: &semver::Version) ->
 }
 
 fn upgrade_dependent_message(name: &str, old_req: &str, new_req: &str) -> Result<()> {
-    let bufwtr = BufferWriter::stdout(ColorChoice::Always);
+    let bufwtr = BufferWriter::stderr(ColorChoice::Always);
     let mut buffer = bufwtr.buffer();
     buffer
         .set_color(ColorSpec::new().set_fg(Some(Color::Green)).set_bold(true))

src/bin/upgrade/main.rs

@@ -151,7 +151,7 @@ fn deprecated_message(message: &str) -> Result<()> {
 }
 
 fn dry_run_message() -> Result<()> {
-    let bufwtr = BufferWriter::stdout(ColorChoice::Always);
+    let bufwtr = BufferWriter::stderr(ColorChoice::Always);
     let mut buffer = bufwtr.buffer();
     buffer
         .set_color(ColorSpec::new().set_fg(Some(Color::Cyan)).set_bold(true))

src/fetch.rs

@@ -98,7 +98,7 @@ pub fn update_registry_index(registry: &Url, quiet: bool) -> Result<()> {
     } else {
         ColorChoice::Never
     };
-    let mut output = StandardStream::stdout(colorchoice);
+    let mut output = StandardStream::stderr(colorchoice);
 
     let index = crates_index::BareIndex::from_url(registry.as_str())?;
     let mut index = index.open_or_clone()?;

src/manifest.rs

@@ -137,7 +137,7 @@ fn print_upgrade_if_necessary(
         if old_version == new_version {
             return Ok(());
         }
-        let bufwtr = BufferWriter::stdout(ColorChoice::Always);
+        let bufwtr = BufferWriter::stderr(ColorChoice::Always);
         let mut buffer = bufwtr.buffer();
         buffer
             .set_color(ColorSpec::new().set_fg(Some(Color::Green)).set_bold(true))

tests/cargo-add.rs

@@ -1441,7 +1441,7 @@ fn adds_dependency_normalized_name() {
             &format!("--manifest-path={}", manifest),
         ])
         .success()
-        .stdout(predicates::str::contains(
+        .stderr(predicates::str::contains(
             "WARN: Added `linked-hash-map` instead of `linked_hash_map`",
         ));
 
@@ -1758,7 +1758,7 @@ fn add_prints_message() {
         .env("CARGO_IS_TEST", "1")
         .assert()
         .success()
-        .stdout(predicates::str::contains(
+        .stderr(predicates::str::contains(
             "Adding docopt v0.6.0 to dependencies",
         ));
 }
@@ -1780,7 +1780,7 @@ fn add_prints_message_with_section() {
         .env("CARGO_IS_TEST", "1")
         .assert()
         .success()
-        .stdout(predicates::str::contains(
+        .stderr(predicates::str::contains(
             "Adding clap v0.1.0 to optional dependencies for target `mytarget`",
         ));
 }
@@ -1802,7 +1802,7 @@ fn add_prints_message_for_dev_deps() {
         .env("CARGO_IS_TEST", "1")
         .assert()
         .success()
-        .stdout(predicates::str::contains(
+        .stderr(predicates::str::contains(
             "Adding docopt v0.8.0 to dev-dependencies",
         ));
 }
@@ -1824,7 +1824,7 @@ fn add_prints_message_for_build_deps() {
         .env("CARGO_IS_TEST", "1")
         .assert()
         .success()
-        .stdout(predicates::str::contains(
+        .stderr(predicates::str::contains(
             "Adding hello-world v0.1.0 to build-dependencies",
         ));
 }
@@ -1956,7 +1956,7 @@ fn add_prints_message_for_features_deps() {
         .env("CARGO_IS_TEST", "1")
         .assert()
         .success()
-        .stdout(predicates::str::contains(
+        .stderr(predicates::str::contains(
             r#"Adding hello-world v0.1.0 to dependencies with features: ["jui"]"#,
         ));
 }

tests/cargo-rm.rs

@@ -244,7 +244,7 @@ fn rm_prints_message() {
         .args(&["rm", "semver", &format!("--manifest-path={}", manifest)])
         .assert()
         .success()
-        .stdout("    Removing semver from dependencies\n");
+        .stderr("    Removing semver from dependencies\n");
 }
 
 #[test]
@@ -261,7 +261,7 @@ fn rm_prints_messages_for_multiple() {
         ])
         .assert()
         .success()
-        .stdout("    Removing semver from dependencies\n    Removing docopt from dependencies\n");
+        .stderr("    Removing semver from dependencies\n    Removing docopt from dependencies\n");
 }
 
 #[test]

tests/cargo-upgrade.rs

@@ -550,5 +550,5 @@ fn upgrade_prints_messages() {
         ])
         .assert()
         .success()
-        .stdout(predicates::str::contains("docopt v0.8 -> v"));
+        .stderr(predicates::str::contains("docopt v0.8 -> v"));
 }