Fix binops handling of __name__

docs/changelog.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## v0.76.2
+
+### Fixed
+
+- For queries using binary expressions between two vectors Prometheus will remove the metric name
+  from resulting series, pint will now also apply the same logic when checking queries.
+
 ## v0.76.1
 
 ### Fixed

internal/checks/alerts_template_test.go

@@ -770,6 +770,18 @@ func TestTemplateCheck(t *testing.T) {
   expr: sum(foo) > 0
   annotations:
     summary: '{{ .Labels.job }} is above zero on {{ $labels.__name__ }}'
+`,
+			checker:    newTemplateCheck,
+			prometheus: noProm,
+			problems:   true,
+		},
+		{
+			description: "__name__ is stripped in foo+foo",
+			content: `
+- alert: Foo
+  expr: foo + on(__name__, job) foo > 0
+  annotations:
+    summary: '{{ .Labels.job }} is above zero on {{ $labels.__name__ }}'
 `,
 			checker:    newTemplateCheck,
 			prometheus: noProm,

internal/checks/alerts_template_test.snap

@@ -152,6 +152,49 @@
 
 ---
 
+[TestTemplateCheck/__name___is_stripped_in_foo+foo - 1]
+- description: __name__ is stripped in foo+foo
+  content: |4
+
+    - alert: Foo
+      expr: foo + on(__name__, job) foo > 0
+      annotations:
+        summary: '{{ .Labels.job }} is above zero on {{ $labels.__name__ }}'
+  output: |
+    3 |   expr: foo + on(__name__, job) foo > 0
+                ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Binary operation between two vectors removes metric names.
+      | [...]
+    5 |     summary: '{{ .Labels.job }} is above zero on {{ $labels.__name__ }}'
+                                                                   ^^^^^^^^^ Template is using `__name__` label but the query results won't have this label.
+  problem:
+    reporter: alerts/template
+    summary: template uses non-existent label
+    details: ""
+    diagnostics:
+        - message: Template is using `__name__` label but the query results won't have this label.
+          pos:
+            - line: 5
+              firstcolumn: 15
+              lastcolumn: 71
+          firstcolumn: 46
+          lastcolumn: 54
+          kind: 0
+        - message: Binary operation between two vectors removes metric names.
+          pos:
+            - line: 3
+              firstcolumn: 9
+              lastcolumn: 39
+          firstcolumn: 1
+          lastcolumn: 27
+          kind: 1
+    lines:
+        first: 2
+        last: 5
+    severity: 2
+    anchor: 0
+
+---
+
 [TestTemplateCheck/abs_/_scalar - 1]
 []
 

internal/parser/utils/source.go

@@ -976,6 +976,7 @@ func parseBinOps(expr string, n *promParser.BinaryExpr) (src []Source) {
 					AddedLabels: n.VectorMatching.Include,
 				})
 			}
+			ls.excludeLabel("Binary operation between two vectors removes metric names.", n.PositionRange(), labels.MetricName)
 			ls.IsConditional, ls.ReturnInfo.IsReturnBool = checkConditions(ls, n.Op, n.ReturnBool)
 			src = append(src, ls)
 		}
@@ -1022,6 +1023,7 @@ func parseBinOps(expr string, n *promParser.BinaryExpr) (src []Source) {
 					AddedLabels: n.VectorMatching.Include,
 				})
 			}
+			rs.excludeLabel("Binary operation between two vectors removes metric names.", n.PositionRange(), labels.MetricName)
 			rs.IsConditional, rs.ReturnInfo.IsReturnBool = checkConditions(rs, n.Op, n.ReturnBool)
 			src = append(src, rs)
 		}
@@ -1065,6 +1067,7 @@ func parseBinOps(expr string, n *promParser.BinaryExpr) (src []Source) {
 					AddedLabels: n.VectorMatching.Include,
 				})
 			}
+			ls.excludeLabel("Binary operation between two vectors removes metric names.", n.PositionRange(), labels.MetricName)
 			ls.IsConditional, ls.ReturnInfo.IsReturnBool = checkConditions(ls, n.Op, n.ReturnBool)
 			src = append(src, ls)
 		}

internal/parser/utils/source_test.go

@@ -288,6 +288,10 @@ count by (dc) (
 	`topk(10, prometheus_build_info*prometheus_ready)`,
 	`bottomk(10, prometheus_build_info*prometheus_ready)`,
 	`histogram_fraction(0, 0.1, metric)`,
+	`foo * foo `,
+	`foo + on(__name__, job) foo `,
+	`foo + on(__name__, job) group_left foo `,
+	`foo + on(__name__, job) group_right foo `,
 }
 
 func TestLabelsSource(t *testing.T) {