Prep for semver bump and document current blocker

This (partially) reverts commit 0bcb724.

This partially reverts the revert (#3051) of #2990. While we can't bump
the version yet, it is worth recovering these changes and documenting
the remaining work.

Author: jtgeibel

Cargo.toml

@@ -72,7 +72,7 @@ parking_lot = "0.11"
 rand = "0.7"
 reqwest = { version = "0.11", features = ["blocking", "gzip", "json"] }
 scheduled-thread-pool = "0.2.0"
-semver = { version = "0.10", features = ["diesel", "serde"] }
+semver = { version = "0.10", features = ["diesel", "serde"] } # TODO: Bump to 0.11 after steveklabnik/semver#217 is resolved
 sentry = "0.22"
 serde = { version = "1.0.0", features = ["derive"] }
 serde_json = "1.0.0"

src/controllers/krate/publish.rs

@@ -25,7 +25,8 @@ pub const MISSING_RIGHTS_ERROR_MESSAGE: &str =
      to accept an invitation to be an owner before \
      publishing.";
 
-pub const WILDCARD_ERROR_MESSAGE: &str = "wildcard (`*`) dependency constraints are not allowed \
+pub const WILDCARD_ERROR_MESSAGE: &str =
+    "wildcard (`*` or `>= 0`) dependency constraints are not allowed \
      on crates.io. See https://doc.rust-lang.org/cargo/faq.html#can-\
      libraries-use--as-a-version-for-their-dependencies for more \
      information";

src/tests/all.rs

@@ -178,6 +178,7 @@ fn env(var: &str) -> String {
     }
 }
 
+#[track_caller]
 fn json<T>(r: &mut AppResponse) -> T
 where
     for<'de> T: serde::Deserialize<'de>,