From 0a0a7db8143c587ad0b84ca84f4bd9300e1b8825 Mon Sep 17 00:00:00 2001
From: Benji Visser <benji@093b.org>
Date: Fri, 18 Aug 2023 21:23:26 -0600
Subject: [PATCH] Adding matching for semver prerelease (#143)

Signed-off-by: Benji Visser <benji@093b.org>
---
 xeol/search/purl.go      | 27 +++++++++++++++++++++++----
 xeol/search/purl_test.go | 36 ++++++++++++++++++++++++++++++++----
 2 files changed, 55 insertions(+), 8 deletions(-)

diff --git a/xeol/search/purl.go b/xeol/search/purl.go
index bae88384..9450958e 100644
--- a/xeol/search/purl.go
+++ b/xeol/search/purl.go
@@ -69,13 +69,27 @@ func ByDistroCpe(store eol.Provider, distro *linux.Release, eolMatchDate time.Ti
 	return match.Match{}, nil
 }
 
-// normalizeSemver returns the major.minor.patch portion of a semver string.
-// it turns versions like 2.7.8p225 into 2.7.8
+// normalizeSemver returns the major.minor.patch portion of a semver string
+// that may have other characters appended to it. We should be very careful
+// here to create matches for patterns we KNOW, because otherwise we could
+// introduce false positives.
 func normalizeSemver(version string) string {
-	re := regexp.MustCompile(`^(\d+\.\d+\.\d+).*`)
+	// For Ruby versions. Example: 2.5.3p105 -> 2.5.3
+	re := regexp.MustCompile(`^(\d+\.\d+\.\d+)p\d+`)
 	return re.ReplaceAllString(version, "$1")
 }
 
+func versionLength(version string) int {
+	parts := strings.SplitN(version, "-", 2)
+	regularVersionParts := strings.Split(parts[0], ".")
+	length := len(regularVersionParts)
+	// increment if there's a pre-release part
+	if len(parts) > 1 && parts[1] != "" {
+		length++
+	}
+	return length
+}
+
 // returnMatchingCycle returns the first cycle that matches the version string.
 // If no cycle matches, an empty cycle is returned.
 func returnMatchingCycle(version string, cycles []eol.Cycle) (eol.Cycle, error) {
@@ -92,11 +106,12 @@ func returnMatchingCycle(version string, cycles []eol.Cycle) (eol.Cycle, error)
 		}
 
 		// match on major, minor, or patch
-		versionLength := len(strings.Split(c.ReleaseCycle, "."))
+		versionLength := versionLength(c.ReleaseCycle)
 		cv, err := semver.NewVersion(c.ReleaseCycle)
 		if err != nil {
 			return eol.Cycle{}, err
 		}
+
 		switch versionLength {
 		case 1:
 			if v.Major() == cv.Major() {
@@ -110,6 +125,10 @@ func returnMatchingCycle(version string, cycles []eol.Cycle) (eol.Cycle, error)
 			if v.Major() == cv.Major() && v.Minor() == cv.Minor() && v.Patch() == cv.Patch() {
 				return c, nil
 			}
+		case 4:
+			if v.Major() == cv.Major() && v.Minor() == cv.Minor() && v.Patch() == cv.Patch() && v.Prerelease() == cv.Prerelease() {
+				return c, nil
+			}
 		}
 	}
 
diff --git a/xeol/search/purl_test.go b/xeol/search/purl_test.go
index 08fa243d..75e1284f 100644
--- a/xeol/search/purl_test.go
+++ b/xeol/search/purl_test.go
@@ -20,19 +20,23 @@ func TestNormalizeSemver(t *testing.T) {
 		},
 		{
 			version:  "1.2.3-rc1",
-			expected: "1.2.3",
+			expected: "1.2.3-rc1",
 		},
 		{
 			version:  "1.2.3-rc1+build1",
-			expected: "1.2.3",
+			expected: "1.2.3-rc1+build1",
 		},
 		{
 			version:  "1.2.3p288",
 			expected: "1.2.3",
 		},
 		{
-			version:  "1.2.3p288+1.3",
-			expected: "1.2.3",
+			version:  "1.1.1-beta",
+			expected: "1.1.1-beta",
+		},
+		{
+			version:  "1.1.1-preview1",
+			expected: "1.1.1-preview1",
 		},
 	}
 
@@ -173,3 +177,27 @@ func TestReturnMatchingCycle(t *testing.T) {
 		})
 	}
 }
+
+func TestVersionLength(t *testing.T) {
+	testCases := []struct {
+		version    string
+		wantLength int
+	}{
+		{"1.0.0", 3},
+		{"1.0.0-beta", 4},
+		{"1.0.0-beta.1", 4},
+		{"2.3", 2},
+		{"2", 1},
+		{"1.1.1-preview1", 4},
+		{"0.0.0", 3},
+		{"0.0.0-alpha", 4},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.version, func(t *testing.T) {
+			if gotLength := versionLength(tt.version); gotLength != tt.wantLength {
+				t.Errorf("versionLength() = %v, want %v", gotLength, tt.wantLength)
+			}
+		})
+	}
+}