Fix pre-releases

CHANGELOG.md

@@ -8,6 +8,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 <!-- next-header -->
 ## [Unreleased] - ReleaseDate
+### Fixed
+- [PR#77](https://github.com/EmbarkStudios/krates/pull/77) resolved [#76](https://github.com/EmbarkStudios/krates/issues/76) by special casing "wildcard" version requirements if the version being tested is a pre-release, as pre-releases must have at least one comparator.
+
 ## [0.16.5] - 2024-01-24
 ### Fixed
 - [PR#75](https://github.com/EmbarkStudios/krates/pull/75) resolved [#74](https://github.com/EmbarkStudios/krates/issues/74) by just always checking version requirements for dependencies. Sigh.

src/builder.rs

@@ -1150,7 +1150,9 @@ impl Builder {
                 // mean there could be a situation where a single crate _could_
                 // be referenced with 0.0.x versions, but...I'll fix that if
                 // someone reports an issue
-                let rdep_version = rdep.pkg.version().parse().expect("failed to parse semver");
+                let rdep_version: semver::Version =
+                    rdep.pkg.version().parse().expect("failed to parse semver");
+                let has_prelease = !rdep_version.pre.is_empty();
 
                 let edges = rdep.dep_kinds.iter().filter_map(|dk| {
                         let mask = match dk.kind {
@@ -1178,7 +1180,11 @@ impl Builder {
                                     return false;
                                 }
 
-                                dep.req.matches(&rdep_version)
+                                // Handle case where a dependency may not have a version requirement, which
+                                // typically happens in the case of non-registry dependencies that use a pre-release
+                                // semver, if the version _is_ a prelease it will never match the empty
+                                // requirement
+                                (has_prelease && dep.req.comparators.is_empty()) || dep.req.matches(&rdep_version)
                             })
                             .unwrap_or_else(|| panic!("cargo metadata resolved a dependency for a dependency not specified by the crate: {rdep:?}"));