Check for file conflicts before install

Fixes #88

pkg/helpers/slice.go

@@ -0,0 +1,10 @@
+package helpers
+
+func Contains(s []string, e string) bool {
+	for _, a := range s {
+		if a == e {
+			return true
+		}
+	}
+	return false
+}

pkg/installer/installer.go

@@ -27,6 +27,7 @@ import (
 	"github.com/mudler/luet/pkg/bus"
 	artifact "github.com/mudler/luet/pkg/compiler/types/artifact"
 	"github.com/mudler/luet/pkg/config"
+	"github.com/mudler/luet/pkg/helpers"
 	fileHelper "github.com/mudler/luet/pkg/helpers/file"
 	"github.com/mudler/luet/pkg/helpers/match"
 	. "github.com/mudler/luet/pkg/logger"
@@ -755,12 +756,61 @@ func (l *LuetInstaller) getFinalizers(allRepos pkg.PackageDatabase, solution sol
 	return toFinalize, nil
 }
 
+func (l *LuetInstaller) checkFileconflicts(toInstall map[string]ArtifactMatch, s *System) error {
+	Info("Checking for file conflicts..")
+	filesToInstall := []string{}
+	for _, m := range toInstall {
+		a, err := l.downloadPackage(m)
+		if err != nil && !l.Options.Force {
+			return errors.Wrap(err, "Failed downloading package")
+		}
+		files, err := a.FileList()
+		if err != nil && !l.Options.Force {
+			return errors.Wrapf(err, "Could not get filelist for %s", a.CompileSpec.Package.HumanReadableString())
+		}
+
+		for _, f := range files {
+			if helpers.Contains(filesToInstall, f) {
+				return fmt.Errorf(
+					"file conflict between packages to be installed",
+				)
+			}
+
+			exists, p, err := s.ExistsPackageFile(f)
+			if err != nil {
+				return errors.Wrap(err, "failed checking into system db")
+			}
+			if exists {
+				return fmt.Errorf(
+					"file conflict between '%s' and '%s' ( file: %s )",
+					p.HumanReadableString(),
+					m.Package.HumanReadableString(),
+					f,
+				)
+			}
+		}
+		filesToInstall = append(filesToInstall, files...)
+	}
+
+	return nil
+}
+
 func (l *LuetInstaller) install(o Option, syncedRepos Repositories, toInstall map[string]ArtifactMatch, p pkg.Packages, solution solver.PackagesAssertions, allRepos pkg.PackageDatabase, s *System) error {
-	// Install packages into rootfs in parallel.
+
+	// Download packages in parallel first
 	if err := l.download(syncedRepos, toInstall); err != nil {
 		return errors.Wrap(err, "Downloading packages")
 	}
 
+	// Check file conflicts
+	if err := l.checkFileconflicts(toInstall, s); err != nil {
+		if !l.Options.Force {
+			return errors.Wrap(err, "file conflict found")
+		} else {
+			Warning("file conflict found", err.Error())
+		}
+	}
+
 	if l.Options.DownloadOnly {
 		return nil
 	}

pkg/installer/system.go

@@ -52,3 +52,18 @@ func (s *System) ExecuteFinalizers(packs []pkg.Package) error {
 	}
 	return errs
 }
+
+func (s *System) ExistsPackageFile(file string) (bool, pkg.Package, error) {
+	for _, p := range s.Database.World() {
+		files, err := s.Database.GetPackageFiles(p)
+		if err != nil {
+			return false, nil, err
+		}
+		for _, f := range files {
+			if f == file {
+				return true, p, nil
+			}
+		}
+	}
+	return false, nil, nil
+}