From cf82eb0ad61edff04e62daa2c0ca8f479299f1cb Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Fri, 4 Feb 2022 12:29:35 -0800
Subject: [PATCH] Improve error on comma after wildcard

---
 src/error.rs              |  8 ++++++++
 src/parse.rs              | 19 +++++++++++--------
 tests/test_version_req.rs |  5 ++++-
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index 4d57950e..56cb69fe 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -10,6 +10,7 @@ pub(crate) enum ErrorKind {
     Overflow(Position),
     EmptySegment(Position),
     IllegalCharacter(Position),
+    CommaAfterWildcard(char),
     UnexpectedAfterWildcard,
     ExcessiveComparators,
 }
@@ -58,6 +59,13 @@ impl Display for Error {
             ErrorKind::IllegalCharacter(pos) => {
                 write!(formatter, "unexpected character in {}", pos)
             }
+            ErrorKind::CommaAfterWildcard(ch) => {
+                write!(
+                    formatter,
+                    "wildcard req ({}) must be the only comparator in the version req",
+                    ch,
+                )
+            }
             ErrorKind::UnexpectedAfterWildcard => {
                 formatter.write_str("unexpected character after wildcard in version req")
             }
diff --git a/src/parse.rs b/src/parse.rs
index 017a5b53..fd10bcfd 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -82,14 +82,17 @@ impl FromStr for VersionReq {
 
     fn from_str(text: &str) -> Result<Self, Self::Err> {
         let text = text.trim_start_matches(' ');
-        if let Some(text) = wildcard(text) {
-            if text.trim_start_matches(' ').is_empty() {
+        if let Some((ch, text)) = wildcard(text) {
+            let rest = text.trim_start_matches(' ');
+            if rest.is_empty() {
                 #[cfg(not(no_const_vec_new))]
                 return Ok(VersionReq::STAR);
                 #[cfg(no_const_vec_new)] // rustc <1.39
                 return Ok(VersionReq {
                     comparators: Vec::new(),
                 });
+            } else if rest.starts_with(',') {
+                return Err(Error::new(ErrorKind::CommaAfterWildcard(ch)));
             } else {
                 return Err(Error::new(ErrorKind::UnexpectedAfterWildcard));
             }
@@ -181,13 +184,13 @@ fn numeric_identifier(input: &str, pos: Position) -> Result<(u64, &str), Error>
     }
 }
 
-fn wildcard(input: &str) -> Option<&str> {
+fn wildcard(input: &str) -> Option<(char, &str)> {
     if let Some(rest) = input.strip_prefix('*') {
-        Some(rest)
+        Some(('*', rest))
     } else if let Some(rest) = input.strip_prefix('x') {
-        Some(rest)
+        Some(('x', rest))
     } else if let Some(rest) = input.strip_prefix('X') {
-        Some(rest)
+        Some(('X', rest))
     } else {
         None
     }
@@ -293,7 +296,7 @@ fn comparator(input: &str) -> Result<(Comparator, Position, &str), Error> {
 
     let (minor, text) = if let Some(text) = text.strip_prefix('.') {
         pos = Position::Minor;
-        if let Some(text) = wildcard(text) {
+        if let Some((_, text)) = wildcard(text) {
             has_wildcard = true;
             if default_op {
                 op = Op::Wildcard;
@@ -309,7 +312,7 @@ fn comparator(input: &str) -> Result<(Comparator, Position, &str), Error> {
 
     let (patch, text) = if let Some(text) = text.strip_prefix('.') {
         pos = Position::Patch;
-        if let Some(text) = wildcard(text) {
+        if let Some((_, text)) = wildcard(text) {
             if default_op {
                 op = Op::Wildcard;
             }
diff --git a/tests/test_version_req.rs b/tests/test_version_req.rs
index d22e092b..51eba1ce 100644
--- a/tests/test_version_req.rs
+++ b/tests/test_version_req.rs
@@ -417,7 +417,10 @@ fn test_leading_digit_in_pre_and_build() {
 #[test]
 fn test_wildcard_and_another() {
     let err = req_err("*, 0.20.0-any");
-    assert_to_string(err, "unexpected character after wildcard in version req");
+    assert_to_string(
+        err,
+        "wildcard req (*) must be the only comparator in the version req",
+    );
 
     let err = req_err("0.20.0-any, *");
     assert_to_string(