Merge pull request #6526 from simonpasquier/cherry-pick-6507

fix: ScrapeClass TLSConfig nil pointer exception (#6507)

pkg/prometheus/promcfg.go

@@ -395,24 +395,25 @@ func (cg *ConfigGenerator) MergeTLSConfigWithScrapeClass(tlsConfig *monitoringv1
 		scrapeClassName = scrapeClass.Name
 	}
 
-	scrapeClass, found := cg.scrapeClasses[scrapeClassName]
-
-	if !found {
-		return tlsConfig
+	scrapeClass = cg.scrapeClasses[scrapeClassName]
+	if scrapeClass == nil {
+		return tlsConfig // could be nil.
 	}
 
-	if tlsConfig == nil && !found {
-		return nil
-	}
+	// scrapeClass exists.
 
-	if tlsConfig != nil && !found {
-		return tlsConfig
+	if tlsConfig == nil {
+		return scrapeClass.TLSConfig // could be nil.
 	}
 
-	if tlsConfig == nil && found {
-		return scrapeClass.TLSConfig
+	// tlsConfig exists.
+
+	if scrapeClass.TLSConfig == nil {
+		return nil
 	}
 
+	// scrapeClass.TLSConfig exists.
+
 	if tlsConfig.CAFile == "" && tlsConfig.SafeTLSConfig.CA == (monitoringv1.SecretOrConfigMap{}) {
 		tlsConfig.CAFile = scrapeClass.TLSConfig.CAFile
 	}

pkg/prometheus/promcfg_test.go

@@ -8056,6 +8056,31 @@ func TestMergeTLSConfigWithScrapeClass(t *testing.T) {
 				},
 			},
 		},
+		{
+			name:      "nil TLSConfig, non-nil ScrapeClass with nil TLSConfig",
+			tlsConfig: nil,
+			scrapeClass: &monitoringv1.ScrapeClass{
+				Name:      "default",
+				TLSConfig: nil,
+			},
+			expectedConfig: &monitoringv1.TLSConfig{
+				CAFile:   "defaultCAFile",
+				CertFile: "defaultCertFile",
+				KeyFile:  "defaultKeyFile",
+			},
+			cg: &ConfigGenerator{
+				defaultScrapeClassName: "default",
+				scrapeClasses: map[string]*monitoringv1.ScrapeClass{
+					"default": {
+						TLSConfig: &monitoringv1.TLSConfig{
+							CAFile:   "defaultCAFile",
+							CertFile: "defaultCertFile",
+							KeyFile:  "defaultKeyFile",
+						},
+					},
+				},
+			},
+		},
 	}
 
 	for _, tt := range tests {