From 03d9c195daed8fca30b642783f35657aa7e32209 Mon Sep 17 00:00:00 2001
From: Aleksandr Nogikh <nogikh@google.com>
Date: Thu, 24 Aug 2023 18:24:04 +0200
Subject: pkg/bisect: test a subset of releases

For older bugs (or for bugs on stable trees), our cause bisection
strategy times out while trying to iterate over all reachable tags.

Try to be smarter and only take a subset of them, thus limiting the time
we spend detecting the bug-free release.

Closes #3376.
---
 pkg/vcs/linux.go | 32 ++++++++------------------------
 pkg/vcs/vcs.go   | 26 ++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 24 deletions(-)

(limited to 'pkg/vcs')

diff --git a/pkg/vcs/linux.go b/pkg/vcs/linux.go
index 270240da7..62319096d 100644
--- a/pkg/vcs/linux.go
+++ b/pkg/vcs/linux.go
@@ -10,7 +10,6 @@ import (
 	"path/filepath"
 	"regexp"
 	"sort"
-	"strconv"
 	"strings"
 	"time"
 
@@ -105,36 +104,21 @@ func gitParseReleaseTags(output []byte, includeRC bool) []string {
 }
 
 func gitReleaseTagToInt(tag string, includeRC bool) uint64 {
-	matches := releaseTagRe.FindStringSubmatchIndex(tag)
-	if matches == nil {
+	v1, v2, rc, v3 := ParseReleaseTag(tag)
+	if v1 < 0 {
 		return 0
 	}
-	v1, err := strconv.ParseUint(tag[matches[2]:matches[3]], 10, 64)
-	if err != nil {
-		return 0
+	if v3 < 0 {
+		v3 = 0
 	}
-	v2, err := strconv.ParseUint(tag[matches[4]:matches[5]], 10, 64)
-	if err != nil {
-		return 0
-	}
-	rc := uint64(999)
-	if matches[6] != -1 {
+	if rc >= 0 {
 		if !includeRC {
 			return 0
 		}
-		rc, err = strconv.ParseUint(tag[matches[6]:matches[7]], 10, 64)
-		if err != nil {
-			return 0
-		}
-	}
-	var v3 uint64
-	if matches[8] != -1 {
-		v3, err = strconv.ParseUint(tag[matches[8]:matches[9]], 10, 64)
-		if err != nil {
-			return 0
-		}
+	} else {
+		rc = 999
 	}
-	return v1*1e9 + v2*1e6 + rc*1e3 + v3
+	return uint64(v1)*1e9 + uint64(v2)*1e6 + uint64(rc)*1e3 + uint64(v3)
 }
 
 func (ctx *linux) EnvForCommit(
diff --git a/pkg/vcs/vcs.go b/pkg/vcs/vcs.go
index ae2b34174..26665bda3 100644
--- a/pkg/vcs/vcs.go
+++ b/pkg/vcs/vcs.go
@@ -10,6 +10,7 @@ import (
 	"net/mail"
 	"regexp"
 	"sort"
+	"strconv"
 	"strings"
 	"time"
 
@@ -268,6 +269,31 @@ func CheckCommitHash(hash string) bool {
 	return gitHashRe.MatchString(hash)
 }
 
+func ParseReleaseTag(tag string) (v1, v2, rc, v3 int) {
+	invalid := func() {
+		v1, v2, rc, v3 = -1, -1, -1, -1
+	}
+	invalid()
+	matches := releaseTagRe.FindStringSubmatch(tag)
+	if matches == nil {
+		return
+	}
+	for ptr, idx := range map[*int]int{
+		&v1: 1, &v2: 2, &rc: 3, &v3: 4,
+	} {
+		if matches[idx] == "" {
+			continue
+		}
+		var err error
+		*ptr, err = strconv.Atoi(matches[idx])
+		if err != nil {
+			invalid()
+			return
+		}
+	}
+	return
+}
+
 func runSandboxed(dir, command string, args ...string) ([]byte, error) {
 	cmd := osutil.Command(command, args...)
 	cmd.Dir = dir
-- 
cgit mrf-deployment