Allow index-update during lockfile regeneration

Since the default index changed to the sparse-index we have had issues with
regenerating the lockfile if the dependency list changed, we relied on the
previous fetch having pulled down details for all crates to use, but now it's
only guaranteed to have details on the crates in the original locked dependency
list. If new versions of crates (like log 0.4.17 -> 0.4.19) changed what
dependencies it used we wouldn't have the details on these dependencies to use
the updated version in the lockfile.

Author: Nemo157

src/docbuilder/rustwide_builder.rs

@@ -408,7 +408,7 @@ impl RustwideBuilder {
                         std::fs::remove_file(cargo_lock)?;
                         Command::new(&self.workspace, self.toolchain.cargo())
                             .cd(build.host_source_dir())
-                            .args(&["generate-lockfile", "-Zno-index-update"])
+                            .args(&["generate-lockfile"])
                             .run()?;
                         Command::new(&self.workspace, self.toolchain.cargo())
                             .cd(build.host_source_dir())
@@ -885,9 +885,39 @@ pub(crate) struct BuildResult {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::test::{assert_redirect, assert_success, wrapper};
+    use crate::test::{assert_redirect, assert_success, wrapper, TestEnvironment};
     use serde_json::Value;
 
+    fn remove_cache_files(env: &TestEnvironment, crate_: &str, version: &str) -> Result<()> {
+        let paths = [
+            format!("cache/index.crates.io-6f17d22bba15001f/{crate_}-{version}.crate"),
+            format!("src/index.crates.io-6f17d22bba15001f/{crate_}-{version}"),
+            format!(
+                "index/index.crates.io-6f17d22bba15001f/.cache/{}/{}/{crate_}",
+                &crate_[0..2],
+                &crate_[2..4]
+            ),
+        ];
+
+        for path in paths {
+            let full_path = env
+                .config()
+                .rustwide_workspace
+                .join("cargo-home/registry")
+                .join(path);
+            if full_path.exists() {
+                info!("deleting {}", full_path.display());
+                if full_path.is_file() {
+                    std::fs::remove_file(full_path)?;
+                } else {
+                    std::fs::remove_dir_all(full_path)?;
+                }
+            }
+        }
+
+        Ok(())
+    }
+
     #[test]
     #[ignore]
     fn test_build_crate() {
@@ -1136,22 +1166,7 @@ mod tests {
             env.override_config(|cfg| cfg.include_default_targets = false);
 
             // if the corrected dependency of the crate was already downloaded we need to remove it
-            let crate_file = env.config().rustwide_workspace.join(
-                "cargo-home/registry/cache/github.com-1ecc6299db9ec823/rand_core-0.5.1.crate",
-            );
-            let src_dir = env
-                .config()
-                .rustwide_workspace
-                .join("cargo-home/registry/src/github.com-1ecc6299db9ec823/rand_core-0.5.1");
-
-            if crate_file.exists() {
-                info!("deleting {}", crate_file.display());
-                std::fs::remove_file(crate_file)?;
-            }
-            if src_dir.exists() {
-                info!("deleting {}", src_dir.display());
-                std::fs::remove_dir_all(src_dir)?;
-            }
+            remove_cache_files(env, "rand_core", "0.5.1")?;
 
             // Specific setup required:
             //  * crate has a binary so that it is published with a lockfile
@@ -1169,6 +1184,28 @@ mod tests {
         });
     }
 
+    #[test]
+    #[ignore]
+    fn test_locked_fails_unlocked_needs_new_unknown_deps() {
+        wrapper(|env| {
+            env.override_config(|cfg| cfg.include_default_targets = false);
+
+            // if the corrected dependency of the crate was already downloaded we need to remove it
+            remove_cache_files(env, "value-bag-sval2", "1.4.1")?;
+
+            // Similar to above, this crate fails to build with the published
+            // lockfile, but generating a new working lockfile requires
+            // introducing a completely new dependency (not just version) which
+            // would not have had its details pulled down from the sparse-index.
+            let crate_ = "docs_rs_test_incorrect_lockfile";
+            let version = "0.2.0";
+            let mut builder = RustwideBuilder::init(env).unwrap();
+            assert!(builder.build_package(crate_, version, PackageKind::CratesIo)?);
+
+            Ok(())
+        });
+    }
+
     #[test]
     #[ignore]
     fn test_rustflags_are_passed_to_build_script() {