Add install preflight safeguards (T-303)

core/installer/verified_package_test.go

@@ -42,6 +42,45 @@ func TestExtractorExtractVerifiedFile(t *testing.T) {
 	}
 }
 
+func TestExtractorExtractVerifiedFileWithCheckPreflightsBeforeStaging(t *testing.T) {
+	archivePath := writeTestZIP(t, []testZIPEntry{
+		{name: "app.json", body: validAppManifest("1.2.3", "bin/App.exe")},
+		{name: "payload/bin/App.exe", body: []byte("executable"), mode: 0o755},
+		{name: "payload/readme.txt", body: []byte("hello")},
+	})
+	destination := filepath.Join(t.TempDir(), "staging")
+	extractor := mustExtractor(t, testLimits())
+	stop := errors.New("pre-extract check stopped")
+
+	_, err := extractor.ExtractVerifiedFileWithCheck(
+		archivePath,
+		destination,
+		verifiedExpectation(t, archivePath, "1.2.3", "bin/App.exe"),
+		func(verified VerifiedPackage) error {
+			if verified.Entrypoint != "bin/App.exe" {
+				t.Fatalf("entrypoint = %q", verified.Entrypoint)
+			}
+			if verified.PayloadFiles != 2 {
+				t.Fatalf("payload files = %d, want 2", verified.PayloadFiles)
+			}
+			if verified.PayloadBytes != int64(len("executable")+len("hello")) {
+				t.Fatalf("payload bytes = %d", verified.PayloadBytes)
+			}
+			return stop
+		},
+	)
+	if !errors.Is(err, stop) {
+		t.Fatalf("ExtractVerifiedFileWithCheck() error = %v, want %v", err, stop)
+	}
+	var packageErr *PackageError
+	if !errors.As(err, &packageErr) || packageErr.Stage != PackageStagePreflight {
+		t.Fatalf("package error = %#v, want preflight stage", packageErr)
+	}
+	if _, statErr := os.Stat(destination); !os.IsNotExist(statErr) {
+		t.Fatalf("preflight failure left staging, stat error = %v", statErr)
+	}
+}
+
 func TestExtractorExtractVerifiedFileRejectsBeforeStaging(t *testing.T) {
 	archivePath := writeTestZIP(t, []testZIPEntry{
 		{name: "app.json", body: validAppManifest("1.2.3", "App.exe")},