Support vendoring git repositories

src/cargo/core/registry.rs

@@ -26,11 +26,11 @@ pub trait Registry {
 
     /// Returns whether or not this registry will return summaries with
     /// checksums listed.
-    ///
-    /// By default, registries do not support checksums.
-    fn supports_checksums(&self) -> bool {
-        false
-    }
+    fn supports_checksums(&self) -> bool;
+
+    /// Returns whether or not this registry will return summaries with
+    /// the `precise` field in the source id listed.
+    fn requires_precise(&self) -> bool;
 }
 
 impl<'a, T: ?Sized + Registry + 'a> Registry for Box<T> {
@@ -39,6 +39,14 @@ impl<'a, T: ?Sized + Registry + 'a> Registry for Box<T> {
              f: &mut FnMut(Summary)) -> CargoResult<()> {
         (**self).query(dep, f)
     }
+
+    fn supports_checksums(&self) -> bool {
+        (**self).supports_checksums()
+    }
+
+    fn requires_precise(&self) -> bool {
+        (**self).requires_precise()
+    }
 }
 
 /// This structure represents a registry of known packages. It internally
@@ -415,6 +423,14 @@ impl<'cfg> Registry for PackageRegistry<'cfg> {
         f(self.lock(override_summary));
         Ok(())
     }
+
+    fn supports_checksums(&self) -> bool {
+        false
+    }
+
+    fn requires_precise(&self) -> bool {
+        false
+    }
 }
 
 fn lock(locked: &LockedMap,
@@ -579,5 +595,13 @@ pub mod test {
                 Ok(())
             }
         }
+
+        fn supports_checksums(&self) -> bool {
+            false
+        }
+
+        fn requires_precise(&self) -> bool {
+            false
+        }
     }
 }

src/cargo/sources/config.rs

@@ -9,7 +9,7 @@ use std::path::{Path, PathBuf};
 
 use url::Url;
 
-use core::{Source, SourceId};
+use core::{Source, SourceId, GitReference};
 use sources::ReplacedSource;
 use util::{Config, ToUrl};
 use util::config::ConfigValue;
@@ -107,19 +107,25 @@ impl<'cfg> SourceConfigMap<'cfg> {
         }
         let new_src = new_id.load(self.config)?;
         let old_src = id.load(self.config)?;
-        if new_src.supports_checksums() != old_src.supports_checksums() {
-            let (supports, no_support) = if new_src.supports_checksums() {
-                (name, orig_name)
-            } else {
-                (orig_name, name)
-            };
+        if !new_src.supports_checksums() && old_src.supports_checksums() {
             bail!("\
-cannot replace `{orig}` with `{name}`, the source `{supports}` supports \
-checksums, but `{no_support}` does not
+cannot replace `{orig}` with `{name}`, the source `{orig}` supports \
+checksums, but `{name}` does not
 
 a lock file compatible with `{orig}` cannot be generated in this situation
-", orig = orig_name, name = name, supports = supports, no_support = no_support);
+", orig = orig_name, name = name);
+        }
+
+        if old_src.requires_precise() && id.precise().is_none() {
+            bail!("\
+the source {orig} requires a lock file to be present first before it can be
+used against vendored source code
+
+remove the source replacement configuration, generate a lock file, and then
+restore the source replacement configuration to continue the build
+", orig = orig_name);
         }
+
         Ok(Box::new(ReplacedSource::new(id, &new_id, new_src)))
     }
 
@@ -153,6 +159,32 @@ a lock file compatible with `{orig}` cannot be generated in this situation
             path.push(s);
             srcs.push(SourceId::for_directory(&path)?);
         }
+        if let Some(val) = table.get("git") {
+            let url = url(val, &format!("source.{}.git", name))?;
+            let try = |s: &str| {
+                let val = match table.get(s) {
+                    Some(s) => s,
+                    None => return Ok(None),
+                };
+                let key = format!("source.{}.{}", name, s);
+                val.string(&key).map(Some)
+            };
+            let reference = match try("branch")? {
+                Some(b) => GitReference::Branch(b.0.to_string()),
+                None => {
+                    match try("tag")? {
+                        Some(b) => GitReference::Tag(b.0.to_string()),
+                        None => {
+                            match try("rev")? {
+                                Some(b) => GitReference::Rev(b.0.to_string()),
+                                None => GitReference::Branch("master".to_string()),
+                            }
+                        }
+                    }
+                }
+            };
+            srcs.push(SourceId::for_git(&url, reference)?);
+        }
         if name == "crates-io" && srcs.is_empty() {
             srcs.push(SourceId::crates_io(self.config)?);
         }

src/cargo/sources/directory.rs

@@ -23,7 +23,7 @@ pub struct DirectorySource<'cfg> {
 
 #[derive(Deserialize)]
 struct Checksum {
-    package: String,
+    package: Option<String>,
     files: HashMap<String, String>,
 }
 
@@ -60,6 +60,10 @@ impl<'cfg> Registry for DirectorySource<'cfg> {
     fn supports_checksums(&self) -> bool {
         true
     }
+
+    fn requires_precise(&self) -> bool {
+        true
+    }
 }
 
 impl<'cfg> Source for DirectorySource<'cfg> {
@@ -133,8 +137,11 @@ impl<'cfg> Source for DirectorySource<'cfg> {
             })?;
 
             let mut manifest = pkg.manifest().clone();
-            let summary = manifest.summary().clone();
-            manifest.set_summary(summary.set_checksum(cksum.package.clone()));
+            let mut summary = manifest.summary().clone();
+            if let Some(ref package) = cksum.package {
+                summary = summary.set_checksum(package.clone());
+            }
+            manifest.set_summary(summary);
             let pkg = Package::new(manifest, pkg.manifest_path());
             self.packages.insert(pkg.package_id().clone(), (pkg, cksum));
         }

src/cargo/sources/git/source.rs

@@ -130,6 +130,14 @@ impl<'cfg> Registry for GitSource<'cfg> {
                       .expect("BUG: update() must be called before query()");
         src.query(dep, f)
     }
+
+    fn supports_checksums(&self) -> bool {
+        false
+    }
+
+    fn requires_precise(&self) -> bool {
+        true
+    }
 }
 
 impl<'cfg> Source for GitSource<'cfg> {

src/cargo/sources/path.rs

@@ -484,6 +484,14 @@ impl<'cfg> Registry for PathSource<'cfg> {
         }
         Ok(())
     }
+
+    fn supports_checksums(&self) -> bool {
+        false
+    }
+
+    fn requires_precise(&self) -> bool {
+        false
+    }
 }
 
 impl<'cfg> Source for PathSource<'cfg> {

src/cargo/sources/registry/mod.rs

@@ -356,6 +356,10 @@ impl<'cfg> Registry for RegistrySource<'cfg> {
     fn supports_checksums(&self) -> bool {
         true
     }
+
+    fn requires_precise(&self) -> bool {
+        false
+    }
 }
 
 impl<'cfg> Source for RegistrySource<'cfg> {

src/cargo/sources/replaced.rs

@@ -33,6 +33,14 @@ impl<'cfg> Registry for ReplacedSource<'cfg> {
                     self.to_replace)
         })
     }
+
+    fn supports_checksums(&self) -> bool {
+        self.inner.supports_checksums()
+    }
+
+    fn requires_precise(&self) -> bool {
+        self.inner.requires_precise()
+    }
 }
 
 impl<'cfg> Source for ReplacedSource<'cfg> {

src/doc/source-replacement.md

@@ -68,6 +68,12 @@ replace-with = "another-source"
 registry = "https://example.com/path/to/index"
 local-registry = "path/to/registry"
 directory = "path/to/vendor"
+
+# Git sources can optionally specify a branch/tag/rev as well
+git = "https://example.com/path/to/repo"
+# branch = "master"
+# tag = "v1.0.1"
+# rev = "313f44e8"
 ```
 
 The `crates-io` represents the crates.io online registry (default source of