From dffdb7f54c981815fc1573ccda6736410ad0df67 Mon Sep 17 00:00:00 2001
From: Mahendra Paipuri <mahendra.paipuri@gmail.com>
Date: Tue, 14 Jan 2025 15:24:13 +0100
Subject: [PATCH] feat: Handle pre and post releases in semver.Compare

Signed-off-by: Mahendra Paipuri <mahendra.paipuri@gmail.com>
---
 pkg/plugin/permissions.go    |  3 +-
 pkg/plugin/resources.go      | 23 ++++++++++++--
 pkg/plugin/resources_test.go | 58 ++++++++++++++++++++++++++++++++++++
 3 files changed, 80 insertions(+), 4 deletions(-)

diff --git a/pkg/plugin/permissions.go b/pkg/plugin/permissions.go
index 06aa00b..9e65f51 100644
--- a/pkg/plugin/permissions.go
+++ b/pkg/plugin/permissions.go
@@ -10,7 +10,6 @@ import (
 	"github.com/mahendrapaipuri/authlib/authn"
 	"github.com/mahendrapaipuri/authlib/authz"
 	"github.com/mahendrapaipuri/authlib/cache"
-	"golang.org/x/mod/semver"
 )
 
 // HasAccess verifies if the current request context has access to certain action.
@@ -77,7 +76,7 @@ func (app *App) GetAuthZClient(req *http.Request) (authz.EnforcementClient, erro
 	// So this check will fail for Grafana < 11.1.0
 	// Set VerifierConfig{DisableTypHeaderCheck: true} for those cases
 	disableTypHeaderCheck := false
-	if semver.Compare(app.grafanaSemVer, "v11.1.0") == -1 {
+	if semverCompare(app.grafanaSemVer, "v11.1.0") == -1 {
 		disableTypHeaderCheck = true
 	}
 
diff --git a/pkg/plugin/resources.go b/pkg/plugin/resources.go
index c1c4641..87772ad 100644
--- a/pkg/plugin/resources.go
+++ b/pkg/plugin/resources.go
@@ -33,7 +33,7 @@ const (
 // convertPanelIDs returns panel IDs based on Grafana version.
 func (app *App) convertPanelIDs(ids []string) []string {
 	// For Grafana < 11.3.0, we can use the IDs as such
-	if semver.Compare(app.grafanaSemVer, "v11.3.0") == -1 {
+	if semverCompare(app.grafanaSemVer, "v11.3.0") == -1 {
 		return ids
 	}
 
@@ -107,7 +107,7 @@ func (app *App) updateConfig(req *http.Request, conf *config.Config) {
 func (app *App) featureTogglesEnabled(ctx context.Context) bool {
 	// If Grafana <= 10.4.3, we use cookies to make request. Moreover feature toggles are
 	// not available for these Grafana versions.
-	if semver.Compare(app.grafanaSemVer, "v10.4.3") <= -1 {
+	if semverCompare(app.grafanaSemVer, "v10.4.3") <= -1 {
 		return false
 	}
 
@@ -393,3 +393,22 @@ func (app *App) registerRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("/report", app.handleReport)
 	mux.HandleFunc("/healthz", app.handleHealth)
 }
+
+// semverCompare compares the semantic version of Grafana versions.
+// Grafana uses "+" as post release suffix and "-" as pre-release
+// suffixes. We take that into account when calling upstream semver
+// package.
+func semverCompare(a, b string) int {
+	switch {
+	case strings.HasPrefix(a, b+"+"):
+		return 1
+	case strings.HasPrefix(b, a+"+"):
+		return -1
+	case strings.HasPrefix(a, b+"-"):
+		return -1
+	case strings.HasPrefix(b, a+"-"):
+		return 1
+	}
+
+	return semver.Compare(a, b)
+}
diff --git a/pkg/plugin/resources_test.go b/pkg/plugin/resources_test.go
index 8f8eaab..4234efb 100644
--- a/pkg/plugin/resources_test.go
+++ b/pkg/plugin/resources_test.go
@@ -110,3 +110,61 @@ func TestReportResource(t *testing.T) {
 		})
 	})
 }
+
+func TestSemverComapre(t *testing.T) {
+	Convey("When comparing semantic versions", t, func() {
+		tests := []struct {
+			name     string
+			a, b     string
+			expected int
+		}{
+			{
+				name:     "regular sem ver comparison",
+				a:        "v1.2.3",
+				b:        "v1.2.5",
+				expected: -1,
+			},
+			{
+				name:     "regular sem ver with pre-release comparison",
+				a:        "v1.2.3",
+				b:        "v1.2.3-rc0",
+				expected: 1,
+			},
+			{
+				name:     "regular sem ver with pre-release comparison with inverse order",
+				a:        "v1.2.3-rc1",
+				b:        "v1.2.3",
+				expected: -1,
+			},
+			{
+				name:     "regular sem ver with post-release comparison",
+				a:        "v1.2.3",
+				b:        "v1.2.3+security-01",
+				expected: -1,
+			},
+			{
+				name:     "regular sem ver with post-release comparison with inverse order",
+				a:        "v1.2.3+security-01",
+				b:        "v1.2.3",
+				expected: 1,
+			},
+			{
+				name:     "comparison with zero version",
+				a:        "v0.0.0",
+				b:        "v1.2.5",
+				expected: -1,
+			},
+			{
+				name:     "comparison with zero version with inverse order",
+				a:        "v1.2.3",
+				b:        "v0.0.0",
+				expected: 1,
+			},
+		}
+
+		for _, test := range tests {
+			got := semverCompare(test.a, test.b)
+			So(got, ShouldEqual, test.expected)
+		}
+	})
+}