detect manifest parse failure during deps fetch

to see if the dependencies manifest including dependencies is valid as well

Author: Skgland

src/prepare.rs

@@ -103,6 +103,7 @@ impl<'a> Prepare<'a> {
 
         let mut yanked_deps = false;
         let mut missing_deps = false;
+        let mut broken_deps = false;
         let mut cmd = Command::new(self.workspace, self.toolchain.cargo()).args(&[
             "generate-lockfile",
             "--manifest-path",
@@ -123,6 +124,8 @@ impl<'a> Prepare<'a> {
                     || line.contains("no matching package named")
                 {
                     missing_deps = true;
+                } else if line.contains("failed to parse manifest at") {
+                    broken_deps = true;
                 }
             })
             .run_capture()
@@ -134,6 +137,9 @@ impl<'a> Prepare<'a> {
             Err(CommandError::ExecutionFailed { status: _, stderr }) if missing_deps => {
                 Err(PrepareError::MissingDependencies(stderr).into())
             }
+            Err(CommandError::ExecutionFailed { status: _, stderr }) if broken_deps => {
+                Err(PrepareError::InvalidCargoTomlSyntaxInDependencies(stderr).into())
+            }
             Err(err) => Err(err.into()),
         }
     }
@@ -150,6 +156,7 @@ pub(crate) fn fetch_deps(
     fetch_build_std_targets: &[&str],
 ) -> anyhow::Result<()> {
     let mut missing_deps = false;
+    let mut broken_deps = false;
     let mut cmd = Command::new(workspace, toolchain.cargo())
         .args(&["fetch", "--manifest-path", "Cargo.toml"])
         .cd(source_dir);
@@ -168,13 +175,19 @@ pub(crate) fn fetch_deps(
             if line.contains("failed to load source for dependency") {
                 missing_deps = true;
             }
+            if line.contains("failed to parse manifest at") {
+                broken_deps = true;
+            }
         })
         .run_capture()
     {
         Ok(_) => Ok(()),
         Err(CommandError::ExecutionFailed { status: _, stderr }) if missing_deps => {
             Err(PrepareError::MissingDependencies(stderr).into())
         }
+        Err(CommandError::ExecutionFailed { status: _, stderr }) if broken_deps => {
+            Err(PrepareError::InvalidCargoTomlSyntaxInDependencies(stderr).into())
+        }
         Err(err) => Err(err.into()),
     }
 }
@@ -384,6 +397,10 @@ pub enum PrepareError {
     /// rejecting it.
     #[error("invalid Cargo.toml syntax")]
     InvalidCargoTomlSyntax,
+    /// A dependencies Cargo.toml is invalid, either due to a TOML syntax error in it or cargo
+    /// rejecting it.
+    #[error("invalid Cargo.toml syntax in dependencies:\n\n{0}")]
+    InvalidCargoTomlSyntaxInDependencies(String),
     /// Some of this crate's dependencies were yanked, preventing Crater from fetching them.
     #[error("the crate depends on yanked dependencies: \n\n{0}")]
     YankedDependencies(String),

tests/buildtest/crates/invalid-cargotoml-content-deps/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "invalid-cargotoml-content-deps"
+version = "0.1.0"
+authors = ["Pietro Albini <pietro@pietroalbini.org>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+parity-db = "=0.2.3"
+# invalid package name in invalid-cargotoml-content is too invalid
+# invalid-cargotoml-content = { git = "https://github.com/rust-lang/rustwide.git", rev = "ee102383cbe40aafdfce7bf04a120226c16a8983" }

tests/buildtest/crates/invalid-cargotoml-content-deps/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

tests/buildtest/mod.rs

@@ -188,6 +188,13 @@ test_prepare_error!(
     InvalidCargoTomlSyntax
 );
 
+test_prepare_error_stderr!(
+    test_invalid_cargotoml_content_deps,
+    "invalid-cargotoml-content-deps",
+    InvalidCargoTomlSyntaxInDependencies,
+    "failed to parse the version requirement `0.11\t` for dependency `parking_lot`"
+);
+
 test_prepare_error_stderr!(
     test_yanked_deps,
     "yanked-deps",