fix(metric name): support multiple __name__ matcher

README.md

@@ -38,9 +38,8 @@ AST: VectorSelector(VectorSelector { name: Some("http_requests_total"), matchers
 
 ## PromQL compliance
 
-This crate declares compatible with [prometheus 0372e25][prom-0372e25], which is
-prometheus release 2.40 at Nov 29, 2022. Any revision on PromQL after this
-commit is not guaranteed.
+This crate declares compatible with [prometheus v2.45.0][prom-v2.45.0], which is
+released at 2023-06-23. Any revision on PromQL after this commit is not guaranteed.
 
 ## Community Extensions
 
@@ -74,5 +73,5 @@ Unless you explicitly state otherwise, any contribution intentionally submitted
 for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
 licensed as above, without any additional terms or conditions.
 
-[prom-0372e25]: https://github.com/prometheus/prometheus/tree/0372e259baf014bbade3134fd79bcdfd8cbdef2c
+[prom-v2.45.0]: https://github.com/prometheus/prometheus/tree/v2.45.0
 [querying-prometheus]: https://prometheus.io/docs/prometheus/latest/querying/basics/

src/label/matcher.rs

@@ -136,13 +136,14 @@ impl Matchers {
         self.matchers.is_empty() || self.matchers.iter().all(|m| m.is_match(""))
     }
 
-    /// find all the matchers whose name equals the specified name.
-    pub fn find_matchers(&self, name: &str) -> Vec<&String> {
-        self.matchers
-            .iter()
-            .filter(|m| m.name.eq_ignore_ascii_case(name))
-            .map(|m| &m.value)
-            .collect()
+    /// find the matcher's value whose name equals the specified name.
+    pub fn find_matcher(&self, name: &str) -> Option<String> {
+        for m in &self.matchers {
+            if m.name.eq(name) {
+                return Some(m.value.clone());
+            }
+        }
+        None
     }
 }
 

src/parser/ast.rs

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::label::{Labels, Matcher, Matchers, METRIC_NAME};
+use crate::label::{Labels, Matchers, METRIC_NAME};
 use crate::parser::token::{
     self, token_display, T_BOTTOMK, T_COUNT_VALUES, T_END, T_QUANTILE, T_START, T_TOPK,
 };
@@ -369,12 +369,11 @@ pub struct VectorSelector {
 
 impl From<String> for VectorSelector {
     fn from(name: String) -> Self {
-        let matcher = Matcher::new_eq_metric_matcher(name.clone());
         VectorSelector {
             name: Some(name),
             offset: None,
             at: None,
-            matchers: Matchers::one(matcher),
+            matchers: Matchers::empty(),
         }
     }
 }
@@ -386,15 +385,14 @@ impl From<String> for VectorSelector {
 /// Basic usage:
 ///
 /// ``` rust
-/// use promql_parser::parser::{Expr, VectorSelector};
-/// use promql_parser::label::{MatchOp, Matcher, Matchers};
+/// use promql_parser::label::Matchers;
+/// use promql_parser::parser::VectorSelector;
 ///
-/// let matcher = Matcher::new_eq_metric_matcher(String::from("foo"));
 /// let vs = VectorSelector {
 ///     name: Some(String::from("foo")),
 ///     offset: None,
 ///     at: None,
-///     matchers: Matchers::one(matcher),
+///     matchers: Matchers::empty(),
 /// };
 ///
 /// assert_eq!(VectorSelector::from("foo"), vs);
@@ -768,12 +766,11 @@ impl From<f64> for Expr {
 /// Basic usage:
 ///
 /// ``` rust
+/// use promql_parser::label::Matchers;
 /// use promql_parser::parser::{Expr, VectorSelector};
-/// use promql_parser::label::{MatchOp, Matcher, Matchers};
 ///
 /// let name = String::from("foo");
-/// let matcher = Matcher::new_eq_metric_matcher(name.clone());
-/// let vs = Expr::new_vector_selector(Some(name), Matchers::one(matcher));
+/// let vs = Expr::new_vector_selector(Some(name), Matchers::empty());
 ///
 /// assert_eq!(Expr::from(VectorSelector::from("foo")), vs.unwrap());
 /// ```
@@ -976,16 +973,13 @@ fn check_ast_for_call(ex: Call) -> Result<Expr, String> {
     }
 
     // special cases from https://prometheus.io/docs/prometheus/latest/querying/functions
-    if name.eq_ignore_ascii_case("exp") {
+    if name.eq("exp") {
         if let Some(val) = ex.args.first().and_then(|ex| ex.scalar_value()) {
             if val.is_nan() || val.is_infinite() {
                 return Ok(Expr::Call(ex));
             }
         }
-    } else if name.eq_ignore_ascii_case("ln")
-        || name.eq_ignore_ascii_case("log2")
-        || name.eq_ignore_ascii_case("log10")
-    {
+    } else if name.eq("ln") || name.eq("log2") || name.eq("log10") {
         if let Some(val) = ex.args.first().and_then(|ex| ex.scalar_value()) {
             if val.is_nan() || val.is_infinite() || val <= 0.0 {
                 return Ok(Expr::Call(ex));
@@ -1032,23 +1026,21 @@ fn check_ast_for_subquery(ex: SubqueryExpr) -> Result<Expr, String> {
 }
 
 fn check_ast_for_vector_selector(ex: VectorSelector) -> Result<Expr, String> {
-    // A Vector selector must contain at least one non-empty matcher to prevent
-    // implicit selection of all metrics (e.g. by a typo).
-    if ex.matchers.is_empty_matchers() {
-        return Err("vector selector must contain at least one non-empty matcher".into());
-    }
-
-    let mut du = ex.matchers.find_matchers(METRIC_NAME);
-    if du.len() >= 2 {
-        // this is to ensure that the err information can be predicted with fixed order
-        du.sort();
-        return Err(format!(
-            "metric name must not be set twice: '{}' or '{}'",
-            du[0], du[1]
-        ));
+    match ex.name {
+        Some(ref name) => match ex.matchers.find_matcher(METRIC_NAME) {
+            Some(val) => Err(format!(
+                "metric name must not be set twice: '{}' or '{}'",
+                name, val
+            )),
+            None => Ok(Expr::VectorSelector(ex)),
+        },
+        None if ex.matchers.is_empty_matchers() => {
+            // When name is None, a vector selector must contain at least one non-empty matcher
+            // to prevent implicit selection of all metrics (e.g. by a typo).
+            Err("vector selector must contain at least one non-empty matcher".into())
+        }
+        _ => Ok(Expr::VectorSelector(ex)),
     }
-
-    Ok(Expr::VectorSelector(ex))
 }
 
 #[cfg(test)]