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allow enabling features for deps with --features
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Fixes #2851
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@bennofs
bennofs committed Jul 14, 2016
1 parent 1c329c4 commit 6f28ef2
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Showing 2 changed files with 100 additions and 42 deletions.
72 changes: 30 additions & 42 deletions src/cargo/core/resolver/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -659,53 +659,41 @@ fn build_features(s: &Summary, method: &Method)
visited: &mut HashSet<String>) -> CargoResult<()> {
if feat.is_empty() { return Ok(()) }

if !visited.insert(feat.to_string()) {
bail!("Cyclic feature dependency: feature `{}` depends \
on itself", feat)
}

used.insert(feat.to_string());

// The lookup of here may fail if the feature corresponds to an optional
// dependency. If that is the case, we simply enable the optional dependency.
//
// Otherwise, we check what other features the feature wants and recursively
// add them.
match s.features().get(feat) {
Some(wanted_features) => {
for entry in wanted_features {
// If the entry is of the form `foo/bar`, then we just lookup package
// `foo` and enable its feature `bar`. We also add `foo` to the used
// set because `foo` might have been an optional dependency.
//
// Otherwise the entry refers to another feature of our current package,
// so we recurse by calling add_feature again, which may end up enabling
// more features or just enabling a dependency (remember, optional
// dependencies create an implicit feature with the same name).
let mut parts = entry.splitn(2, '/');
let feat_or_package = parts.next().unwrap();
match parts.next() {
Some(feat) => {
let package = feat_or_package;
used.insert(package.to_string());
deps.entry(package.to_string())
.or_insert(Vec::new())
.push(feat.to_string());
}
None => {
let feat = feat_or_package;
try!(add_feature(s, feat, deps, used, visited));
// If this feature is of the form `foo/bar`, then we just lookup package
// `foo` and enable its feature `bar`. Otherwise this feature is of the
// form `foo` and we need to recurse to enable the feature `foo` for our
// own package, which may end up enabling more features or just enabling
// a dependency.
let mut parts = feat.splitn(2, '/');
let feat_or_package = parts.next().unwrap();
match parts.next() {
Some(feat) => {
let package = feat_or_package;
used.insert(package.to_string());
deps.entry(package.to_string())
.or_insert(Vec::new())
.push(feat.to_string());
}
None => {
let feat = feat_or_package;
if !visited.insert(feat.to_string()) {
bail!("Cyclic feature dependency: feature `{}` depends \
on itself", feat)
}
used.insert(feat.to_string());
match s.features().get(feat) {
Some(recursive) => {
for f in recursive {
try!(add_feature(s, f, deps, used, visited));
}
}
None => {
deps.entry(feat.to_string()).or_insert(Vec::new());
}
}
}
None => {
deps.entry(feat.to_string()).or_insert(Vec::new());
visited.remove(&feat.to_string());
}
}

visited.remove(&feat.to_string());

Ok(())
}
}
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70 changes: 70 additions & 0 deletions tests/features.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -881,3 +881,73 @@ fn activating_feature_activates_dep() {
assert_that(p.cargo_process("build").arg("--features").arg("a").arg("-v"),
execs().with_status(0));
}

#[test]
fn dep_feature_in_cmd_line() {
let p = project("foo")
.file("Cargo.toml", r#"
[project]
name = "foo"
version = "0.0.1"
authors = []
[dependencies.derived]
path = "derived"
"#)
.file("src/main.rs", r#"
extern crate derived;
fn main() { derived::test(); }
"#)
.file("derived/Cargo.toml", r#"
[package]
name = "derived"
version = "0.0.1"
authors = []
[dependencies.bar]
path = "../bar"
[features]
default = []
derived-feat = ["bar/some-feat"]
"#)
.file("derived/src/lib.rs", r#"
extern crate bar;
pub use bar::test;
"#)
.file("bar/Cargo.toml", r#"
[package]
name = "bar"
version = "0.0.1"
authors = []
[features]
some-feat = []
"#)
.file("bar/src/lib.rs", r#"
#[cfg(feature = "some-feat")]
pub fn test() { print!("test"); }
"#);

// The foo project requires that feature "some-feat" in "bar" is enabled.
// Building without any features enabled should fail:
assert_that(p.cargo_process("build"),
execs().with_status(101));

// We should be able to enable the feature "derived-feat", which enables "some-feat",
// on the command line. The feature is enabled, thus building should be successful:
assert_that(p.cargo_process("build").arg("--features").arg("derived/derived-feat"),
execs().with_status(0));

// Trying to enable features of transitive dependencies is an error
assert_that(p.cargo_process("build").arg("--features").arg("bar/some-feat"),
execs().with_status(101).with_stderr("\
[ERROR] Package `foo v0.0.1 ([..])` does not have these features: `bar`
"));

// Hierarchical feature specification should still be disallowed
assert_that(p.cargo_process("build").arg("--features").arg("derived/bar/some-feat"),
execs().with_status(101).with_stderr("\
[ERROR] feature names may not contain slashes: `bar/some-feat`
"));
}

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