From d92a4d8ff7d1a90caf9fcac9bf120c360455d8d9 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sun, 12 Mar 2023 10:58:56 -0700
Subject: [PATCH] Add a dedicated error for parsing Version from empty string

---
 src/error.rs          | 2 ++
 src/parse.rs          | 4 ++++
 tests/test_version.rs | 5 +----
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index a514e3f1..93b05ee8 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -2,6 +2,7 @@ use crate::parse::Error;
 use core::fmt::{self, Debug, Display};
 
 pub(crate) enum ErrorKind {
+    Empty,
     UnexpectedEnd(Position),
     UnexpectedChar(Position, char),
     UnexpectedCharAfter(Position, char),
@@ -31,6 +32,7 @@ impl std::error::Error for Error {}
 impl Display for Error {
     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
         match &self.kind {
+            ErrorKind::Empty => formatter.write_str("empty string, expected a semver version"),
             ErrorKind::UnexpectedEnd(pos) => {
                 write!(formatter, "unexpected end of input while parsing {}", pos)
             }
diff --git a/src/parse.rs b/src/parse.rs
index 6a8f6ffb..e92d87ab 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -26,6 +26,10 @@ impl FromStr for Version {
     type Err = Error;
 
     fn from_str(text: &str) -> Result<Self, Self::Err> {
+        if text.is_empty() {
+            return Err(Error::new(ErrorKind::Empty));
+        }
+
         let mut pos = Position::Major;
         let (major, text) = numeric_identifier(text, pos)?;
         let text = dot(text, pos)?;
diff --git a/tests/test_version.rs b/tests/test_version.rs
index 93a528c1..de3628fa 100644
--- a/tests/test_version.rs
+++ b/tests/test_version.rs
@@ -12,10 +12,7 @@ use semver::{BuildMetadata, Prerelease, Version};
 #[test]
 fn test_parse() {
     let err = version_err("");
-    assert_to_string(
-        err,
-        "unexpected end of input while parsing major version number",
-    );
+    assert_to_string(err, "empty string, expected a semver version");
 
     let err = version_err("  ");
     assert_to_string(