update: Added error message for when v is prefixed with version

Author: Pyr0de

src/cargo/core/source_id.rs

@@ -523,8 +523,16 @@ impl SourceId {
         version: semver::Version,
         precise: &str,
     ) -> CargoResult<SourceId> {
-        let precise = semver::Version::parse(precise)
-            .with_context(|| format!("invalid version format for precise version `{precise}`"))?;
+        let precise = semver::Version::parse(precise).with_context(|| {
+            if let Some(stripped) = precise.strip_prefix("v") {
+                return format!(
+                    "the version provided, `{precise}` is not a \
+                    valid SemVer version\n\n\
+                    help: try changing the version to `{stripped}`",
+                );
+            }
+            format!("invalid version format for precise version `{precise}`")
+        })?;
 
         Ok(SourceId::wrap(SourceIdInner {
             precise: Some(Precise::Updated {

tests/testsuite/update.rs

@@ -2737,7 +2737,9 @@ fn prefixed_v_in_version() {
     p.cargo("update bar --precise v1.0.1")
         .with_status(101)
         .with_stderr_data(str![[r#"
-[ERROR] invalid version format for precise version `v1.0.1`
+[ERROR] the version provided, `v1.0.1` is not a valid SemVer version
+
+[HELP] try changing the version to `1.0.1`
 
 Caused by:
   unexpected character 'v' while parsing major version number