Enhance Uninstall and resolve conflict sets

Compute a minimum conflict set over the uninstall.

Adds also tests for specific cases covered by Uninstall now

pkg/package/database.go

@@ -15,4 +15,6 @@
 
 package pkg
 
+// Database is a merely simple in-memory db.
+// FIXME: Use a proper structure or delegate to third-party
 var Database map[string]string = map[string]string{}

pkg/package/package.go

@@ -23,10 +23,13 @@ import (
 	"hash/crc32"
 
 	"github.com/crillab/gophersat/bf"
+	version "github.com/hashicorp/go-version"
 
 	"github.com/jinzhu/copier"
 )
 
+// Package is a package interface (TBD)
+// FIXME: Currently some of the methods are returning DefaultPackages due to JSON serialization of the package
 type Package interface {
 	Encode() (string, error)
 	SetState(state State) Package
@@ -39,8 +42,14 @@ type Package interface {
 
 	GetRequires() []*DefaultPackage
 	GetConflicts() []*DefaultPackage
+	Expand([]Package) ([]Package, error)
+
+	GetName() string
+	GetVersion() string
+	RequiresContains(Package) bool
 }
 
+// DefaultPackage represent a standard package definition
 type DefaultPackage struct {
 	Name             string
 	Version          string
@@ -51,16 +60,21 @@ type DefaultPackage struct {
 	IsSet            bool
 }
 
-type PackageUse []string
+// State represent the package state
 type State string
 
+// NewPackage returns a new package
 func NewPackage(name, version string, requires []*DefaultPackage, conflicts []*DefaultPackage) *DefaultPackage {
 	return &DefaultPackage{Name: name, Version: version, PackageRequires: requires, PackageConflicts: conflicts}
 }
+
+// GetFingerPrint returns a UUID of the package.
+// FIXME: this needs to be unique, now just name is generalized
 func (p *DefaultPackage) GetFingerPrint() string {
 	return p.Name
 }
 
+// AddUse adds a use to a package
 func (p *DefaultPackage) AddUse(use string) {
 	for _, v := range p.UseFlags {
 		if v == use {
@@ -70,6 +84,7 @@ func (p *DefaultPackage) AddUse(use string) {
 	p.UseFlags = append(p.UseFlags, use)
 }
 
+// RemoveUse removes a use to a package
 func (p *DefaultPackage) RemoveUse(use string) {
 
 	for i := len(p.UseFlags) - 1; i >= 0; i-- {
@@ -80,6 +95,8 @@ func (p *DefaultPackage) RemoveUse(use string) {
 
 }
 
+// Encode encodes the package to string.
+// It returns an ID which can be used to retrieve the package later on.
 func (p *DefaultPackage) Encode() (string, error) {
 	res, err := json.Marshal(p)
 	if err != nil {
@@ -103,7 +120,12 @@ func (p *DefaultPackage) IsFlagged(b bool) Package {
 func (p *DefaultPackage) Flagged() bool {
 	return p.IsSet
 }
-
+func (p *DefaultPackage) GetName() string {
+	return p.Name
+}
+func (p *DefaultPackage) GetVersion() string {
+	return p.Version
+}
 func (p *DefaultPackage) SetState(state State) Package {
 	p.State = state
 	return p
@@ -128,6 +150,30 @@ func (p *DefaultPackage) Clone() Package {
 	return new
 }
 
+func (p *DefaultPackage) Expand(world []Package) ([]Package, error) {
+
+	var versionsInWorld []Package
+	for _, w := range world {
+		if w.GetName() == p.GetName() {
+
+			v, err := version.NewVersion(w.GetVersion())
+			if err != nil {
+				return nil, err
+			}
+			constraints, err := version.NewConstraint(p.GetVersion())
+			if err != nil {
+				return nil, err
+			}
+			if constraints.Check(v) {
+				versionsInWorld = append(versionsInWorld, w)
+			}
+
+		}
+	}
+
+	return versionsInWorld, nil
+}
+
 func DecodePackage(ID string) (Package, error) {
 
 	pa, ok := Database[ID]
@@ -158,6 +204,20 @@ func NormalizeFlagged(p Package) {
 	}
 }
 
+func (p *DefaultPackage) RequiresContains(s Package) bool {
+	for _, re := range p.GetRequires() {
+		if re.GetFingerPrint() == s.GetFingerPrint() {
+			return true
+		}
+
+		if re.RequiresContains(s) {
+			return true
+		}
+	}
+
+	return false
+}
+
 func (p *DefaultPackage) BuildFormula() ([]bf.Formula, error) {
 	encodedA, err := p.IsFlagged(true).Encode()
 	if err != nil {

pkg/package/package_suite_test.go

@@ -0,0 +1,28 @@
+// Copyright © 2019 Ettore Di Giacinto <mudler@gentoo.org>
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with this program; if not, see <http://www.gnu.org/licenses/>.
+
+package pkg_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestSolver(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Package Suite")
+}

pkg/package/package_test.go

@@ -0,0 +1,39 @@
+// Copyright © 2019 Ettore Di Giacinto <mudler@gentoo.org>
+//
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 2 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with this program; if not, see <http://www.gnu.org/licenses/>.
+
+package pkg_test
+
+import (
+	. "github.com/mudler/luet/pkg/package"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Package", func() {
+	Context("Simple package", func() {
+		a := NewPackage("A", ">=1.0", []*DefaultPackage{}, []*DefaultPackage{})
+		a1 := NewPackage("A", "1.0", []*DefaultPackage{}, []*DefaultPackage{})
+		a11 := NewPackage("A", "1.1", []*DefaultPackage{}, []*DefaultPackage{})
+		a01 := NewPackage("A", "0.1", []*DefaultPackage{}, []*DefaultPackage{})
+		It("Expands correctly", func() {
+			lst, err := a.Expand([]Package{a1, a11, a01})
+			Expect(err).ToNot(HaveOccurred())
+			Expect(lst).To(ContainElement(a11))
+			Expect(lst).To(ContainElement(a1))
+			Expect(lst).ToNot(ContainElement(a01))
+			Expect(len(lst)).To(Equal(2))
+		})
+	})
+})

pkg/solver/decoder.go

@@ -19,11 +19,15 @@ import (
 	pkg "github.com/mudler/luet/pkg/package"
 )
 
+// PackageAssert represent a package assertion.
+// It is composed of a Package and a Value which is indicating the absence or not
+// of the associated package state.
 type PackageAssert struct {
 	Package pkg.Package
 	Value   bool
 }
 
+// DecodeModel decodes a model from the SAT solver to package assertions (PackageAssert)
 func DecodeModel(model map[string]bool) ([]PackageAssert, error) {
 	ass := make([]PackageAssert, 0)
 	for k, v := range model {

pkg/solver/solver.go

@@ -22,19 +22,24 @@ import (
 	pkg "github.com/mudler/luet/pkg/package"
 )
 
-type State interface{ Encode() string }
-
+// PackageSolver is an interface to a generic package solving algorithm
 type PackageSolver interface {
 	SetWorld(p []pkg.Package)
 	Install(p []pkg.Package) ([]PackageAssert, error)
 	Uninstall(candidate pkg.Package) ([]pkg.Package, error)
+	ConflictsWithInstalled(p pkg.Package) (bool, error)
+	ConflictsWith(p pkg.Package, ls []pkg.Package) (bool, error)
 }
+
+// Solver is the default solver for luet
 type Solver struct {
 	Wanted    []pkg.Package
 	Installed []pkg.Package
 	World     []pkg.Package
 }
 
+// NewSolver accepts as argument two lists of packages, the first is the initial set,
+// the second represent all the known packages.
 func NewSolver(init []pkg.Package, w []pkg.Package) PackageSolver {
 	for _, v := range init {
 		pkg.NormalizeFlagged(v)
@@ -45,6 +50,8 @@ func NewSolver(init []pkg.Package, w []pkg.Package) PackageSolver {
 	return &Solver{Installed: init, World: w}
 }
 
+// SetWorld is a setter for the list of all known packages to the solver
+
 func (s *Solver) SetWorld(p []pkg.Package) {
 	s.World = p
 }
@@ -59,17 +66,35 @@ func (s *Solver) noRulesWorld() bool {
 	return true
 }
 
-func (s *Solver) BuildWorld() (bf.Formula, error) {
+func (s *Solver) BuildInstalled() (bf.Formula, error) {
 	var formulas []bf.Formula
-	// for _, p := range s.Installed {
-	// 	solvable, err := p.BuildFormula()
-	// 	if err != nil {
-	// 		return nil, err
-	// 	}
-	// 	//f = bf.And(f, solvable)
-	// 	formulas = append(formulas, solvable...)
+	for _, p := range s.Installed {
+		solvable, err := p.BuildFormula()
+		if err != nil {
+			return nil, err
+		}
+		//f = bf.And(f, solvable)
+		formulas = append(formulas, solvable...)
+
+	}
+	return bf.And(formulas...), nil
+
+}
+
+// BuildWorld builds the formula which olds the requirements from the package definitions
+// which are available (global state)
+func (s *Solver) BuildWorld(includeInstalled bool) (bf.Formula, error) {
+	var formulas []bf.Formula
+	// NOTE: This block should be enabled in case of very old systems with outdated world sets
+	if includeInstalled {
+		solvable, err := s.BuildInstalled()
+		if err != nil {
+			return nil, err
+		}
+		//f = bf.And(f, solvable)
+		formulas = append(formulas, solvable)
+	}
 
-	// }
 	for _, p := range s.World {
 		solvable, err := p.BuildFormula()
 		if err != nil {
@@ -80,13 +105,75 @@ func (s *Solver) BuildWorld() (bf.Formula, error) {
 	return bf.And(formulas...), nil
 }
 
-// world is ok with Px (installed-x-th) and removal of package (candidate?)
+func (s *Solver) ConflictsWith(p pkg.Package, ls []pkg.Package) (bool, error) {
+	pkg.NormalizeFlagged(p)
+	var formulas []bf.Formula
+
+	if s.noRulesWorld() {
+		return false, nil
+	}
+
+	encodedP, err := p.IsFlagged(true).Encode()
+	if err != nil {
+		return false, err
+	}
+	P := bf.Var(encodedP)
+
+	r, err := s.BuildWorld(false)
+	if err != nil {
+		return false, err
+	}
+	formulas = append(formulas, bf.And(bf.Not(P), r))
+
+	for _, i := range ls {
+		if i.GetFingerPrint() == p.GetFingerPrint() {
+			continue
+		}
+		// XXX: Skip check on any of its requires ?  ( Drop to avoid removing system packages when selecting an uninstall)
+		// if i.RequiresContains(p) {
+		// 	fmt.Println("Requires found")
+		// 	continue
+		// }
+
+		encodedI, err := i.Encode()
+		if err != nil {
+			return false, err
+		}
+		I := bf.Var(encodedI)
+		formulas = append(formulas, bf.And(I, r))
+	}
+	model := bf.Solve(bf.And(formulas...))
+	if model == nil {
+		return true, nil
+	}
+
+	return false, nil
+
+}
+
+func (s *Solver) ConflictsWithInstalled(p pkg.Package) (bool, error) {
+	return s.ConflictsWith(p, s.Installed)
+}
+
+// Uninstall takes a candidate package and return a list of packages that would be removed
+// in order to purge the candidate. Returns error if unsat.
+// XXX: this should be turned in unsat/sat instead of computing the reverse set
+// e.g. world is ok with Px (installed-x-th) and removal of package (candidate?)
 // collect unsatisfieds and repeat until we get no more unsatisfieds
 func (s *Solver) Uninstall(candidate pkg.Package) ([]pkg.Package, error) {
 	var res []pkg.Package
+
+	// Build a fake "Installed" - Candidate and its requires tree
+	var InstalledMinusCandidate []pkg.Package
+	for _, i := range s.Installed {
+		if i.GetFingerPrint() != candidate.GetFingerPrint() && !candidate.RequiresContains(i) {
+			InstalledMinusCandidate = append(InstalledMinusCandidate, i)
+		}
+	}
+
+	// Get the requirements to install the candidate
 	saved := s.Installed
 	s.Installed = []pkg.Package{}
-
 	asserts, err := s.Install([]pkg.Package{candidate})
 	if err != nil {
 		return nil, err
@@ -95,7 +182,24 @@ func (s *Solver) Uninstall(candidate pkg.Package) ([]pkg.Package, error) {
 
 	for _, a := range asserts {
 		if a.Value && a.Package.Flagged() {
-			res = append(res, a.Package.IsFlagged(false))
+
+			c, err := s.ConflictsWithInstalled(a.Package)
+			if err != nil {
+				return nil, err
+			}
+			if !c { // If doesn't conflict with installed we just consider it for removal
+				res = append(res, a.Package.IsFlagged(false))
+			} else {
+				// If does conficlits, give it another chance checking conflicts if in case we didn't installed our candidate and all the requires in the system
+				c, err := s.ConflictsWith(a.Package, InstalledMinusCandidate)
+				if err != nil {
+					return nil, err
+				}
+				if !c {
+					res = append(res, a.Package.IsFlagged(false))
+				}
+			}
+
 		}
 
 	}
@@ -103,10 +207,10 @@ func (s *Solver) Uninstall(candidate pkg.Package) ([]pkg.Package, error) {
 	return res, nil
 }
 
+// BuildFormula builds the main solving formula that is evaluated by the sat solver.
 func (s *Solver) BuildFormula() (bf.Formula, error) {
-	//f := bf.True
 	var formulas []bf.Formula
-	r, err := s.BuildWorld()
+	r, err := s.BuildWorld(false)
 	if err != nil {
 		return nil, err
 	}
@@ -146,6 +250,7 @@ func (s *Solver) solve(f bf.Formula) (map[string]bool, bf.Formula, error) {
 	return model, f, nil
 }
 
+// Solve builds the formula given the current state and returns package assertions
 func (s *Solver) Solve() ([]PackageAssert, error) {
 
 	f, err := s.BuildFormula()
@@ -162,6 +267,8 @@ func (s *Solver) Solve() ([]PackageAssert, error) {
 	return DecodeModel(model)
 }
 
+// Install given a list of packages, returns package assertions to indicate the packages that must be installed in the system in order
+// to statisfy all the constraints
 func (s *Solver) Install(coll []pkg.Package) ([]PackageAssert, error) {
 	for _, v := range coll {
 		v.IsFlagged(false)

pkg/solver/solver_test.go

@@ -150,6 +150,126 @@ var _ = Describe("Solver", func() {
 			Expect(len(solution)).To(Equal(1))
 		})
 
+		It("Find conflicts", func() {
+
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D := pkg.NewPackage("D", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+
+			B := pkg.NewPackage("B", "", []*pkg.DefaultPackage{A}, []*pkg.DefaultPackage{})
+
+			s := NewSolver([]pkg.Package{A, B, C, D}, []pkg.Package{A, B, C, D})
+			val, err := s.ConflictsWithInstalled(A)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(val).To(BeTrue())
+
+		})
+
+		It("Find nested conflicts", func() {
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D := pkg.NewPackage("D", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{D}, []*pkg.DefaultPackage{})
+
+			B := pkg.NewPackage("B", "", []*pkg.DefaultPackage{A}, []*pkg.DefaultPackage{})
+
+			s := NewSolver([]pkg.Package{A, B, C, D}, []pkg.Package{A, B, C, D})
+			val, err := s.ConflictsWithInstalled(D)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(val).To(BeTrue())
+		})
+
+		It("Doesn't find nested conflicts", func() {
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D := pkg.NewPackage("D", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{D}, []*pkg.DefaultPackage{})
+
+			B := pkg.NewPackage("B", "", []*pkg.DefaultPackage{A}, []*pkg.DefaultPackage{})
+
+			s := NewSolver([]pkg.Package{A, B, C, D}, []pkg.Package{A, B, C, D})
+			val, err := s.ConflictsWithInstalled(C)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(val).ToNot(BeTrue())
+		})
+
+		It("Doesn't find conflicts", func() {
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D := pkg.NewPackage("D", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+
+			B := pkg.NewPackage("B", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+
+			s := NewSolver([]pkg.Package{A, B, C, D}, []pkg.Package{A, B, C, D})
+			val, err := s.ConflictsWithInstalled(C)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(val).ToNot(BeTrue())
+		})
+		It("Uninstalls simple packages not in world correctly", func() {
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D := pkg.NewPackage("D", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			B := pkg.NewPackage("B", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+
+			s := NewSolver([]pkg.Package{A, B, C, D}, []pkg.Package{B, C, D})
+
+			solution, err := s.Uninstall(A)
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(solution).To(ContainElement(A.IsFlagged(false)))
+
+			//	Expect(solution).To(ContainElement(PackageAssert{Package: C.IsFlagged(true), Value: true}))
+			Expect(len(solution)).To(Equal(1))
+		})
+
+		It("Uninstalls complex packages not in world correctly", func() {
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D := pkg.NewPackage("D", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			B := pkg.NewPackage("B", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{B}, []*pkg.DefaultPackage{})
+
+			s := NewSolver([]pkg.Package{A, B, C, D}, []pkg.Package{B, C, D})
+
+			solution, err := s.Uninstall(A)
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(solution).To(ContainElement(A.IsFlagged(false)))
+
+			Expect(len(solution)).To(Equal(1))
+		})
+
+		It("Uninstalls complex packages correctly, even if shared deps are required by system packages", func() {
+			D := pkg.NewPackage("D", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			B := pkg.NewPackage("B", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{B}, []*pkg.DefaultPackage{})
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{B}, []*pkg.DefaultPackage{})
+
+			s := NewSolver([]pkg.Package{A, B, C, D}, []pkg.Package{A, B, C, D})
+
+			solution, err := s.Uninstall(A)
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(solution).To(ContainElement(A.IsFlagged(false)))
+			Expect(solution).ToNot(ContainElement(B.IsFlagged(false)))
+
+			Expect(len(solution)).To(Equal(1))
+		})
+
+		It("Uninstalls complex packages in world correctly", func() {
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D := pkg.NewPackage("D", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			B := pkg.NewPackage("B", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{C}, []*pkg.DefaultPackage{})
+
+			s := NewSolver([]pkg.Package{A, C, D}, []pkg.Package{A, B, C, D})
+
+			solution, err := s.Uninstall(A)
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(solution).To(ContainElement(A.IsFlagged(false)))
+			Expect(solution).To(ContainElement(C.IsFlagged(false)))
+
+			Expect(len(solution)).To(Equal(2))
+		})
+
 		It("Uninstalls complex package correctly", func() {
 			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
 			D := pkg.NewPackage("D", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
@@ -162,10 +282,8 @@ var _ = Describe("Solver", func() {
 			solution, err := s.Uninstall(A)
 			Expect(solution).To(ContainElement(A.IsFlagged(false)))
 			Expect(solution).To(ContainElement(B.IsFlagged(false)))
-			//Expect(solution).To(ContainElement(C.IsFlagged(true)))
 			Expect(solution).To(ContainElement(D.IsFlagged(false)))
 
-			//	Expect(solution).To(ContainElement(PackageAssert{Package: C.IsFlagged(true), Value: true}))
 			Expect(len(solution)).To(Equal(3))
 			Expect(err).ToNot(HaveOccurred())