From b1d875410ae0bbec9203f6ba3dce21923bdca773 Mon Sep 17 00:00:00 2001
From: jochen <jschoubben@gmail.com>
Date: Fri, 23 Oct 2026 09:10:09 +0200
Subject: [PATCH] logrotate: dry-run the base against logs of its own, so the
 shut-off unit level does not stat the machine's /var/log (issue 1891)

The unit level runs in bubblewrap, where /var/log is not there; the base's
/var/log/wtmp block has no missingok, so logrotate -d failed its stat and
every mesh-catalog check that reached this test failed.
---
 .../cmd/logrotate-tools/manifest_test.go      | 43 ++++++++++++++++---
 1 file changed, 38 insertions(+), 5 deletions(-)

diff --git a/modules/logrotate/cmd/logrotate-tools/manifest_test.go b/modules/logrotate/cmd/logrotate-tools/manifest_test.go
index b6ca26cd..84bbfaa0 100644
--- a/modules/logrotate/cmd/logrotate-tools/manifest_test.go
+++ b/modules/logrotate/cmd/logrotate-tools/manifest_test.go
@@ -39,12 +39,8 @@ func TestTheBaseParses(t *testing.T) {
 		t.Skip("logrotate is not installed here; the base configuration is not dry-run")
 	}
 	dir := t.TempDir()
-	content := strings.ReplaceAll(templateText(t, manifest(t).resource(t, "config")), "include "+RulesDir, "include "+filepath.Join(dir, "d"))
-	if err := os.Mkdir(filepath.Join(dir, "d"), 0o755); err != nil {
-		t.Fatal(err)
-	}
 	conf := filepath.Join(dir, "logrotate.conf")
-	if err := os.WriteFile(conf, []byte(content), 0o644); err != nil {
+	if err := os.WriteFile(conf, []byte(dryRunBase(t, dir)), 0o644); err != nil {
 		t.Fatal(err)
 	}
 	out, err := exec.Command(logrotate, "-d", "-s", filepath.Join(dir, "state"), conf).CombinedOutput()
@@ -52,3 +48,40 @@ func TestTheBaseParses(t *testing.T) {
 		t.Fatalf("logrotate -d: %v\n%s", err, out)
 	}
 }
+
+// The dry run proves the base parses, not what the machine's logs are: the unit level runs shut off in
+// bubblewrap (mesh-sdk buildstep.Isolated), where /var/log is not there, and a base block without
+// missingok then fails its stat (issue 1891).
+func TestTheDryRunReadsNothingOfTheMachine(t *testing.T) {
+	dir := t.TempDir()
+	content := dryRunBase(t, dir)
+	for _, machine := range []string{"include " + RulesDir, "/var/log/"} {
+		if strings.Contains(content, machine) {
+			t.Fatalf("the dry run's base still names %s of the machine:\n%s", machine, content)
+		}
+	}
+	for _, log := range []string{"wtmp", "btmp"} {
+		if _, err := os.Stat(filepath.Join(dir, "log", log)); err != nil {
+			t.Fatalf("the base's own log %s is not in the dry run's directory: %v", log, err)
+		}
+	}
+}
+
+// dryRunBase is the base configuration pointed into dir: its include at dir/d, and its own logs at dir/log,
+// both made there.
+func dryRunBase(t *testing.T, dir string) string {
+	t.Helper()
+	content := strings.ReplaceAll(templateText(t, manifest(t).resource(t, "config")), "include "+RulesDir, "include "+filepath.Join(dir, "d"))
+	content = strings.ReplaceAll(content, "/var/log/", filepath.Join(dir, "log")+"/")
+	for _, d := range []string{"d", "log"} {
+		if err := os.Mkdir(filepath.Join(dir, d), 0o755); err != nil {
+			t.Fatal(err)
+		}
+	}
+	for _, log := range []string{"wtmp", "btmp"} {
+		if err := os.WriteFile(filepath.Join(dir, "log", log), nil, 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+	return content
+}