Add support for Package provides

Add "provides" field in packages (which affect both runtime and buildtime deps).
It replaces all the occurences in the deptree before solving, actually
allowing to swap packages and provide virtuals. Along with a mechanism
for package rename #25.

pkg/compiler/compiler.go

@@ -441,6 +441,7 @@ func (cs *LuetCompiler) ComputeDepTree(p CompilationSpec) (solver.PackagesAssert
 	}
 
 	dependencies := solution.Order(cs.Database, p.GetPackage().GetFingerPrint())
+
 	assertions := solver.PackagesAssertions{}
 	for _, assertion := range dependencies { //highly dependent on the order
 		if assertion.Value {

pkg/compiler/compiler_test.go

@@ -316,6 +316,90 @@ var _ = Describe("Compiler", func() {
 			Expect(helpers.Exists(spec.Rel("extra-layer-0.1.package.tar"))).To(BeTrue())
 		})
 
+		It("Compiles with provides support", func() {
+			generalRecipe := tree.NewCompilerRecipe(pkg.NewInMemoryDatabase(false))
+			tmpdir, err := ioutil.TempDir("", "package")
+			Expect(err).ToNot(HaveOccurred())
+			defer os.RemoveAll(tmpdir) // clean up
+
+			err = generalRecipe.Load("../../tests/fixtures/provides")
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(len(generalRecipe.GetDatabase().GetPackages())).To(Equal(3))
+
+			compiler := NewLuetCompiler(sd.NewSimpleDockerBackend(), generalRecipe.GetDatabase())
+
+			spec, err := compiler.FromPackage(&pkg.DefaultPackage{Name: "d", Category: "test", Version: "1.0"})
+			Expect(err).ToNot(HaveOccurred())
+
+			//		err = generalRecipe.Tree().ResolveDeps(3)
+			//		Expect(err).ToNot(HaveOccurred())
+
+			spec.SetOutputPath(tmpdir)
+
+			artifacts, errs := compiler.CompileParallel(1, false, NewLuetCompilationspecs(spec))
+			Expect(errs).To(BeNil())
+			Expect(len(artifacts)).To(Equal(1))
+			Expect(len(artifacts[0].GetDependencies())).To(Equal(1))
+
+			for _, artifact := range artifacts {
+				Expect(helpers.Exists(artifact.GetPath())).To(BeTrue())
+				Expect(helpers.Untar(artifact.GetPath(), tmpdir, false)).ToNot(HaveOccurred())
+			}
+			Expect(helpers.Untar(spec.Rel("c-test-1.0.package.tar"), tmpdir, false)).ToNot(HaveOccurred())
+
+			Expect(helpers.Exists(spec.Rel("d"))).To(BeTrue())
+			Expect(helpers.Exists(spec.Rel("dd"))).To(BeTrue())
+			Expect(helpers.Exists(spec.Rel("c"))).To(BeTrue())
+			Expect(helpers.Exists(spec.Rel("cd"))).To(BeTrue())
+
+			Expect(helpers.Exists(spec.Rel("d-test-1.0.metadata.yaml"))).To(BeTrue())
+
+			Expect(helpers.Exists(spec.Rel("c-test-1.0.metadata.yaml"))).To(BeTrue())
+		})
+
+		It("Compiles with provides and selectors support", func() {
+			// Same test as before, but fixtures differs
+			generalRecipe := tree.NewCompilerRecipe(pkg.NewInMemoryDatabase(false))
+			tmpdir, err := ioutil.TempDir("", "package")
+			Expect(err).ToNot(HaveOccurred())
+			defer os.RemoveAll(tmpdir) // clean up
+
+			err = generalRecipe.Load("../../tests/fixtures/provides_selector")
+			Expect(err).ToNot(HaveOccurred())
+
+			Expect(len(generalRecipe.GetDatabase().GetPackages())).To(Equal(3))
+
+			compiler := NewLuetCompiler(sd.NewSimpleDockerBackend(), generalRecipe.GetDatabase())
+
+			spec, err := compiler.FromPackage(&pkg.DefaultPackage{Name: "d", Category: "test", Version: "1.0"})
+			Expect(err).ToNot(HaveOccurred())
+
+			//		err = generalRecipe.Tree().ResolveDeps(3)
+			//		Expect(err).ToNot(HaveOccurred())
+
+			spec.SetOutputPath(tmpdir)
+
+			artifacts, errs := compiler.CompileParallel(1, false, NewLuetCompilationspecs(spec))
+			Expect(errs).To(BeNil())
+			Expect(len(artifacts)).To(Equal(1))
+			Expect(len(artifacts[0].GetDependencies())).To(Equal(1))
+
+			for _, artifact := range artifacts {
+				Expect(helpers.Exists(artifact.GetPath())).To(BeTrue())
+				Expect(helpers.Untar(artifact.GetPath(), tmpdir, false)).ToNot(HaveOccurred())
+			}
+			Expect(helpers.Untar(spec.Rel("c-test-1.0.package.tar"), tmpdir, false)).ToNot(HaveOccurred())
+
+			Expect(helpers.Exists(spec.Rel("d"))).To(BeTrue())
+			Expect(helpers.Exists(spec.Rel("dd"))).To(BeTrue())
+			Expect(helpers.Exists(spec.Rel("c"))).To(BeTrue())
+			Expect(helpers.Exists(spec.Rel("cd"))).To(BeTrue())
+
+			Expect(helpers.Exists(spec.Rel("d-test-1.0.metadata.yaml"))).To(BeTrue())
+
+			Expect(helpers.Exists(spec.Rel("c-test-1.0.metadata.yaml"))).To(BeTrue())
+		})
 		It("Compiles revdeps", func() {
 			generalRecipe := tree.NewCompilerRecipe(pkg.NewInMemoryDatabase(false))
 			tmpdir, err := ioutil.TempDir("", "revdep")

pkg/package/database_boltdb.go

@@ -34,7 +34,8 @@ import (
 
 type BoltDatabase struct {
 	sync.Mutex
-	Path string
+	Path             string
+	ProvidesDatabase map[string]map[string]Package
 }
 
 func NewBoltDatabase(path string) PackageDatabase {
@@ -42,7 +43,7 @@ func NewBoltDatabase(path string) PackageDatabase {
 	// 	BoltInstance = &BoltDatabase{Path: path}
 	// }
 	//return BoltInstance, nil
-	return &BoltDatabase{Path: path}
+	return &BoltDatabase{Path: path, ProvidesDatabase: map[string]map[string]Package{}}
 }
 
 func (db *BoltDatabase) Get(s string) (string, error) {
@@ -85,6 +86,11 @@ func (db *BoltDatabase) Retrieve(ID string) ([]byte, error) {
 }
 
 func (db *BoltDatabase) FindPackage(tofind Package) (Package, error) {
+	// Provides: Return the replaced package here
+	if provided, err := db.getProvide(tofind); err == nil {
+		return provided, nil
+	}
+
 	p := &DefaultPackage{}
 	bolt, err := storm.Open(db.Path, storm.BoltOptions(0600, &bbolt.Options{Timeout: 30 * time.Second}))
 	if err != nil {
@@ -196,9 +202,62 @@ func (db *BoltDatabase) CreatePackage(p Package) (string, error) {
 		return "", errors.Wrap(err, "Error saving package to "+db.Path)
 	}
 
+	// Create extra cache between package -> []versions
+	db.Lock()
+	defer db.Unlock()
+	// TODO: Replace with a bolt implementation (and not in memory)
+	// Provides: Store package provides, we will reuse this when walking deps
+	for _, provide := range dp.Provides {
+		if _, ok := db.ProvidesDatabase[provide.GetPackageName()]; !ok {
+			db.ProvidesDatabase[provide.GetPackageName()] = make(map[string]Package)
+
+		}
+
+		db.ProvidesDatabase[provide.GetPackageName()][provide.GetVersion()] = p
+	}
+
 	return strconv.Itoa(dp.ID), err
 }
 
+// Dup from memory implementation
+func (db *BoltDatabase) getProvide(p Package) (Package, error) {
+	db.Lock()
+	pa, ok := db.ProvidesDatabase[p.GetPackageName()][p.GetVersion()]
+	if !ok {
+		versions, ok := db.ProvidesDatabase[p.GetPackageName()]
+		db.Unlock()
+
+		if !ok {
+			return nil, errors.New("No versions found for package")
+		}
+
+		for ve, _ := range versions {
+
+			v, err := version.NewVersion(p.GetVersion())
+			if err != nil {
+				return nil, err
+			}
+			constraints, err := version.NewConstraint(ve)
+			if err != nil {
+				return nil, err
+			}
+
+			if constraints.Check(v) {
+				pa, ok := db.ProvidesDatabase[p.GetPackageName()][ve]
+				if !ok {
+					return nil, errors.New("No versions found for package")
+				}
+				return pa, nil //pick the first (we shouldn't have providers that are conflicting)
+				// TODO: A find dbcall here would recurse, but would give chance to have providers of providers
+			}
+		}
+
+		return nil, errors.New("No package provides this")
+	}
+	db.Unlock()
+	return db.FindPackage(pa)
+}
+
 func (db *BoltDatabase) Clean() error {
 	db.Lock()
 	defer db.Unlock()
@@ -298,6 +357,10 @@ func (db *BoltDatabase) FindPackageCandidate(p Package) (Package, error) {
 // FindPackages return the list of the packages beloging to cat/name  (any versions in requested range)
 // FIXME: Optimize, see inmemorydb
 func (db *BoltDatabase) FindPackages(p Package) ([]Package, error) {
+	// Provides: Treat as the replaced package here
+	if provided, err := db.getProvide(p); err == nil {
+		p = provided
+	}
 	var versionsInWorld []Package
 	for _, w := range db.World() {
 		if w.GetName() != p.GetName() || w.GetCategory() != p.GetCategory() {

pkg/package/database_mem.go

@@ -25,27 +25,30 @@ import (
 )
 
 var DBInMemoryInstance = &InMemoryDatabase{
-	Mutex:          &sync.Mutex{},
-	FileDatabase:   map[string][]string{},
-	Database:       map[string]string{},
-	CacheNoVersion: map[string]map[string]interface{}{},
+	Mutex:            &sync.Mutex{},
+	FileDatabase:     map[string][]string{},
+	Database:         map[string]string{},
+	CacheNoVersion:   map[string]map[string]interface{}{},
+	ProvidesDatabase: map[string]map[string]Package{},
 }
 
 type InMemoryDatabase struct {
 	*sync.Mutex
-	Database       map[string]string
-	FileDatabase   map[string][]string
-	CacheNoVersion map[string]map[string]interface{}
+	Database         map[string]string
+	FileDatabase     map[string][]string
+	CacheNoVersion   map[string]map[string]interface{}
+	ProvidesDatabase map[string]map[string]Package
 }
 
 func NewInMemoryDatabase(singleton bool) PackageDatabase {
 	// In memoryDB is a singleton
 	if !singleton {
 		return &InMemoryDatabase{
-			Mutex:          &sync.Mutex{},
-			FileDatabase:   map[string][]string{},
-			Database:       map[string]string{},
-			CacheNoVersion: map[string]map[string]interface{}{},
+			Mutex:            &sync.Mutex{},
+			FileDatabase:     map[string][]string{},
+			Database:         map[string]string{},
+			CacheNoVersion:   map[string]map[string]interface{}{},
+			ProvidesDatabase: map[string]map[string]Package{},
 		}
 	}
 	return DBInMemoryInstance
@@ -142,6 +145,17 @@ func (db *InMemoryDatabase) CreatePackage(p Package) (string, error) {
 	// Create extra cache between package -> []versions
 	db.Lock()
 	defer db.Unlock()
+
+	// Provides: Store package provides, we will reuse this when walking deps
+	for _, provide := range pd.Provides {
+		if _, ok := db.ProvidesDatabase[provide.GetPackageName()]; !ok {
+			db.ProvidesDatabase[provide.GetPackageName()] = make(map[string]Package)
+
+		}
+
+		db.ProvidesDatabase[provide.GetPackageName()][provide.GetVersion()] = p
+	}
+
 	_, ok = db.CacheNoVersion[p.GetPackageName()]
 	if !ok {
 		db.CacheNoVersion[p.GetPackageName()] = make(map[string]interface{})
@@ -151,6 +165,43 @@ func (db *InMemoryDatabase) CreatePackage(p Package) (string, error) {
 	return ID, nil
 }
 
+func (db *InMemoryDatabase) getProvide(p Package) (Package, error) {
+	db.Lock()
+	pa, ok := db.ProvidesDatabase[p.GetPackageName()][p.GetVersion()]
+	if !ok {
+		versions, ok := db.ProvidesDatabase[p.GetPackageName()]
+		db.Unlock()
+
+		if !ok {
+			return nil, errors.New("No versions found for package")
+		}
+
+		for ve, _ := range versions {
+
+			v, err := version.NewVersion(p.GetVersion())
+			if err != nil {
+				return nil, err
+			}
+			constraints, err := version.NewConstraint(ve)
+			if err != nil {
+				return nil, err
+			}
+
+			if constraints.Check(v) {
+				pa, ok := db.ProvidesDatabase[p.GetPackageName()][ve]
+				if !ok {
+					return nil, errors.New("No versions found for package")
+				}
+				return pa, nil
+			}
+		}
+
+		return nil, errors.New("No package provides this")
+	}
+	db.Unlock()
+	return db.FindPackage(pa)
+}
+
 func (db *InMemoryDatabase) encodePackage(p Package) (string, string, error) {
 	pd, ok := p.(*DefaultPackage)
 	if !ok {
@@ -167,6 +218,12 @@ func (db *InMemoryDatabase) encodePackage(p Package) (string, string, error) {
 }
 
 func (db *InMemoryDatabase) FindPackage(p Package) (Package, error) {
+
+	// Provides: Return the replaced package here
+	if provided, err := db.getProvide(p); err == nil {
+		return provided, nil
+	}
+
 	return db.GetPackage(p.GetFingerPrint())
 }
 
@@ -189,6 +246,11 @@ func (db *InMemoryDatabase) FindPackageVersions(p Package) ([]Package, error) {
 
 // FindPackages return the list of the packages beloging to cat/name (any versions in requested range)
 func (db *InMemoryDatabase) FindPackages(p Package) ([]Package, error) {
+
+	// Provides: Treat as the replaced package here
+	if provided, err := db.getProvide(p); err == nil {
+		p = provided
+	}
 	versions, ok := db.CacheNoVersion[p.GetPackageName()]
 	if !ok {
 		return nil, errors.New("No versions found for package")

pkg/package/database_test.go

@@ -76,6 +76,31 @@ var _ = Describe("Database", func() {
 			Expect(pack).To(Equal(a3))
 
 		})
+
+		It("Provides replaces definitions", func() {
+			db := NewInMemoryDatabase(false)
+			a := NewPackage("A", "1.0", []*DefaultPackage{}, []*DefaultPackage{})
+			a1 := NewPackage("A", "1.1", []*DefaultPackage{}, []*DefaultPackage{})
+			a3 := NewPackage("A", "1.3", []*DefaultPackage{}, []*DefaultPackage{})
+
+			a3.SetProvides([]*DefaultPackage{{Name: "A", Category: "", Version: "1.0"}})
+			Expect(a3.GetProvides()).To(Equal([]*DefaultPackage{{Name: "A", Category: "", Version: "1.0"}}))
+
+			_, err := db.CreatePackage(a)
+			Expect(err).ToNot(HaveOccurred())
+
+			_, err = db.CreatePackage(a1)
+			Expect(err).ToNot(HaveOccurred())
+
+			_, err = db.CreatePackage(a3)
+			Expect(err).ToNot(HaveOccurred())
+
+			s := NewPackage("A", "1.0", []*DefaultPackage{}, []*DefaultPackage{})
+
+			pack, err := db.FindPackage(s)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(pack).To(Equal(a3))
+		})
 	})
 
 })

pkg/package/package.go

@@ -46,6 +46,9 @@ type Package interface {
 	Conflicts([]*DefaultPackage) Package
 	Revdeps(PackageDatabase) []Package
 
+	GetProvides() []*DefaultPackage
+	SetProvides([]*DefaultPackage) Package
+
 	GetRequires() []*DefaultPackage
 	GetConflicts() []*DefaultPackage
 	Expand(PackageDatabase) ([]Package, error)
@@ -132,6 +135,7 @@ type DefaultPackage struct {
 	PackageRequires  []*DefaultPackage `json:"requires"`  // Affects YAML field names too.
 	PackageConflicts []*DefaultPackage `json:"conflicts"` // Affects YAML field names too.
 	IsSet            bool              `json:"set"`       // Affects YAML field names too.
+	Provides         []*DefaultPackage `json:"provides"`  // Affects YAML field names too.
 
 	// TODO: Annotations?
 
@@ -270,7 +274,13 @@ func (p *DefaultPackage) SetCategory(s string) {
 func (p *DefaultPackage) GetUses() []string {
 	return p.UseFlags
 }
-
+func (p *DefaultPackage) GetProvides() []*DefaultPackage {
+	return p.Provides
+}
+func (p *DefaultPackage) SetProvides(req []*DefaultPackage) Package {
+	p.Provides = req
+	return p
+}
 func (p *DefaultPackage) GetRequires() []*DefaultPackage {
 	return p.PackageRequires
 }
@@ -436,7 +446,11 @@ func (pack *DefaultPackage) BuildFormula(definitiondb PackageDatabase, db Packag
 	var formulas []bf.Formula
 	for _, requiredDef := range p.GetRequires() {
 		required, err := definitiondb.FindPackage(requiredDef)
-		if err != nil {
+		if err != nil || requiredDef.IsSelector() {
+			if err == nil {
+				requiredDef = required.(*DefaultPackage)
+			}
+
 			packages, err := definitiondb.FindPackages(requiredDef)
 			if err != nil || len(packages) == 0 {
 				required = requiredDef
@@ -515,8 +529,11 @@ func (pack *DefaultPackage) BuildFormula(definitiondb PackageDatabase, db Packag
 
 	for _, requiredDef := range p.GetConflicts() {
 		required, err := definitiondb.FindPackage(requiredDef)
-		if err != nil {
-			packages, err := requiredDef.Expand(definitiondb)
+		if err != nil || requiredDef.IsSelector() {
+			if err == nil {
+				requiredDef = required.(*DefaultPackage)
+			}
+			packages, err := definitiondb.FindPackages(requiredDef)
 			if err != nil || len(packages) == 0 {
 				required = requiredDef
 			} else {

pkg/package/package_test.go

@@ -129,6 +129,9 @@ var _ = Describe("Package", func() {
 			Expect(a01.RequiresContains(definitions, a11)).To(BeTrue())
 			Expect(a01.RequiresContains(definitions, a)).To(BeTrue())
 			Expect(a.RequiresContains(definitions, a11)).ToNot(BeTrue())
+			Expect(a.IsSelector()).To(BeTrue())
+			Expect(a1.IsSelector()).To(BeFalse())
+
 		})
 	})
 

pkg/solver/decoder.go

@@ -168,12 +168,16 @@ func (assertions PackagesAssertions) Order(definitiondb pkg.PackageDatabase, fin
 	}
 
 	sort.Sort(unorderedAssertions)
-
 	// Build a topological graph
 	//graph := toposort.NewGraph(len(unorderedAssertions))
 	//	graph.AddNodes(fingerprints...)
 	for _, a := range unorderedAssertions {
-		for _, requiredDef := range a.Package.GetRequires() {
+		currentPkg := a.Package
+		for _, requiredDef := range currentPkg.GetRequires() {
+			if def, err := definitiondb.FindPackage(requiredDef); err == nil { // Provides: Get a chance of being override here
+				requiredDef = def.(*pkg.DefaultPackage)
+			}
+
 			// We cannot search for fingerprint, as we could have selector in versions.
 			// We know that the assertions are unique for packages, so look for a package with such name in the assertions
 			req := assertions.SearchByName(requiredDef.GetPackageName())
@@ -182,7 +186,7 @@ func (assertions PackagesAssertions) Order(definitiondb pkg.PackageDatabase, fin
 			}
 
 			// Expand also here, as we need to order them (or instead the solver should give back the dep correctly?)
-			graph.AddEdge(a.Package.GetFingerPrint(), requiredDef.GetFingerPrint())
+			graph.AddEdge(currentPkg.GetFingerPrint(), requiredDef.GetFingerPrint())
 		}
 	}
 	result, err := graph.TopSort(fingerprint)

pkg/solver/solver_test.go

@@ -393,6 +393,128 @@ var _ = Describe("Solver", func() {
 			Expect(len(solution)).To(Equal(5))
 			Expect(err).ToNot(HaveOccurred())
 		})
+
+		It("Support provides", func() {
+
+			E := pkg.NewPackage("E", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D2 := pkg.NewPackage("D", "1.9", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D := pkg.NewPackage("D", "1.8", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D1 := pkg.NewPackage("D", "1.4", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			B := pkg.NewPackage("B", "1.1", []*pkg.DefaultPackage{&pkg.DefaultPackage{Name: "D", Version: ">=1.0"}}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{&pkg.DefaultPackage{Name: "D", Version: ">=1.0"}}, []*pkg.DefaultPackage{})
+
+			D2.SetProvides([]*pkg.DefaultPackage{{Name: "E"}})
+			A2 := pkg.NewPackage("A", "1.3", []*pkg.DefaultPackage{&pkg.DefaultPackage{Name: "E", Version: ""}}, []*pkg.DefaultPackage{})
+
+			for _, p := range []pkg.Package{A, B, C, D, D1, D2, A2, E} {
+				_, err := dbDefinitions.CreatePackage(p)
+				Expect(err).ToNot(HaveOccurred())
+			}
+
+			for _, p := range []pkg.Package{} {
+				_, err := dbInstalled.CreatePackage(p)
+				Expect(err).ToNot(HaveOccurred())
+			}
+			s = NewSolver(dbInstalled, dbDefinitions, db)
+
+			solution, err := s.Install([]pkg.Package{A2, B})
+			Expect(solution).To(ContainElement(PackageAssert{Package: A2, Value: true}))
+			Expect(solution).To(ContainElement(PackageAssert{Package: B, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: D1, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: D, Value: true}))
+			Expect(solution).To(ContainElement(PackageAssert{Package: D2, Value: true}))
+			Expect(solution).To(ContainElement(PackageAssert{Package: D, Value: false}))
+			Expect(solution).To(ContainElement(PackageAssert{Package: D1, Value: false}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: E, Value: true}))
+
+			Expect(len(solution)).To(Equal(5))
+			Expect(err).ToNot(HaveOccurred())
+		})
+
+		It("Support provides with versions", func() {
+			E := pkg.NewPackage("E", "1.3", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D2 := pkg.NewPackage("D", "1.9", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D := pkg.NewPackage("D", "1.8", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D1 := pkg.NewPackage("D", "1.4", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			B := pkg.NewPackage("B", "1.1", []*pkg.DefaultPackage{&pkg.DefaultPackage{Name: "D", Version: ">=1.0"}}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{&pkg.DefaultPackage{Name: "D", Version: ">=1.0"}}, []*pkg.DefaultPackage{})
+
+			D2.SetProvides([]*pkg.DefaultPackage{{Name: "E", Version: "1.3"}})
+			A2 := pkg.NewPackage("A", "1.3", []*pkg.DefaultPackage{&pkg.DefaultPackage{Name: "E", Version: ">=1.0"}}, []*pkg.DefaultPackage{})
+
+			for _, p := range []pkg.Package{A, B, C, D, D1, D2, A2, E} {
+				_, err := dbDefinitions.CreatePackage(p)
+				Expect(err).ToNot(HaveOccurred())
+			}
+
+			for _, p := range []pkg.Package{} {
+				_, err := dbInstalled.CreatePackage(p)
+				Expect(err).ToNot(HaveOccurred())
+			}
+			s = NewSolver(dbInstalled, dbDefinitions, db)
+
+			solution, err := s.Install([]pkg.Package{A2})
+			Expect(solution).To(ContainElement(PackageAssert{Package: A2, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: B, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: D1, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: D, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: C, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: A, Value: true}))
+
+			Expect(solution).To(ContainElement(PackageAssert{Package: D2, Value: true}))
+			Expect(solution).To(ContainElement(PackageAssert{Package: D, Value: false}))
+			Expect(solution).To(ContainElement(PackageAssert{Package: D1, Value: false}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: E, Value: true}))
+
+			Expect(len(solution)).To(Equal(4))
+			Expect(err).ToNot(HaveOccurred())
+		})
+
+		It("Support provides with selectors", func() {
+			E := pkg.NewPackage("E", "1.3", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+
+			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D2 := pkg.NewPackage("D", "1.9", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D := pkg.NewPackage("D", "1.8", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			D1 := pkg.NewPackage("D", "1.4", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})
+			B := pkg.NewPackage("B", "1.1", []*pkg.DefaultPackage{&pkg.DefaultPackage{Name: "D", Version: ">=1.0"}}, []*pkg.DefaultPackage{})
+			A := pkg.NewPackage("A", "", []*pkg.DefaultPackage{&pkg.DefaultPackage{Name: "D", Version: ">=1.0"}}, []*pkg.DefaultPackage{})
+
+			D2.SetProvides([]*pkg.DefaultPackage{{Name: "E", Version: ">=1.3"}})
+			A2 := pkg.NewPackage("A", "1.3", []*pkg.DefaultPackage{&pkg.DefaultPackage{Name: "E", Version: ">=1.0"}}, []*pkg.DefaultPackage{})
+
+			for _, p := range []pkg.Package{A, B, C, D, D1, D2, A2, E} {
+				_, err := dbDefinitions.CreatePackage(p)
+				Expect(err).ToNot(HaveOccurred())
+			}
+
+			for _, p := range []pkg.Package{} {
+				_, err := dbInstalled.CreatePackage(p)
+				Expect(err).ToNot(HaveOccurred())
+			}
+			s = NewSolver(dbInstalled, dbDefinitions, db)
+
+			solution, err := s.Install([]pkg.Package{A2})
+			Expect(solution).To(ContainElement(PackageAssert{Package: A2, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: B, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: D1, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: D, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: C, Value: true}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: A, Value: true}))
+
+			Expect(solution).To(ContainElement(PackageAssert{Package: D2, Value: true}))
+			Expect(solution).To(ContainElement(PackageAssert{Package: D, Value: false}))
+			Expect(solution).To(ContainElement(PackageAssert{Package: D1, Value: false}))
+			Expect(solution).ToNot(ContainElement(PackageAssert{Package: E, Value: true}))
+
+			Expect(len(solution)).To(Equal(4))
+			Expect(err).ToNot(HaveOccurred())
+		})
+
 		It("Uninstalls simple package correctly", func() {
 
 			C := pkg.NewPackage("C", "", []*pkg.DefaultPackage{}, []*pkg.DefaultPackage{})

tests/fixtures/provides/c/build.yaml

@@ -0,0 +1,7 @@
+image: "alpine"
+prelude:
+  - echo foo > /test
+  - echo bar > /test2
+steps:
+  - echo c > /c
+  - echo c > /cd

tests/fixtures/provides/c/definition.yaml

@@ -0,0 +1,7 @@
+category: "test"
+name: "c"
+version: "1.0"
+provides:
+- category: "bar"
+  name: "foo"
+  version: "1.0"

tests/fixtures/provides/d/build.yaml

@@ -0,0 +1,11 @@
+prelude:
+  - echo foo > /test
+  - echo bar > /test2
+steps:
+  - echo s > /d
+  - echo dd > /dd
+requires:
+- category: "bar"
+  name: "foo"
+  version: "1.0"
+

tests/fixtures/provides/d/definition.yaml

@@ -0,0 +1,3 @@
+category: "test"
+name: "d"
+version: "1.0"

tests/fixtures/provides/virtual/foo/definition.yaml

@@ -0,0 +1,3 @@
+name: "foo"
+version: "1.0"
+category: "bar"

tests/fixtures/provides_selector/c/build.yaml

@@ -0,0 +1,7 @@
+image: "alpine"
+prelude:
+  - echo foo > /test
+  - echo bar > /test2
+steps:
+  - echo c > /c
+  - echo c > /cd

tests/fixtures/provides_selector/c/definition.yaml

@@ -0,0 +1,7 @@
+category: "test"
+name: "c"
+version: "1.0"
+provides:
+- category: "bar"
+  name: "foo"
+  version: ">=1.0"

tests/fixtures/provides_selector/d/build.yaml

@@ -0,0 +1,11 @@
+prelude:
+  - echo foo > /test
+  - echo bar > /test2
+steps:
+  - echo s > /d
+  - echo dd > /dd
+requires:
+- category: "bar"
+  name: "foo"
+  version: ">=1.0"
+

tests/fixtures/provides_selector/d/definition.yaml

@@ -0,0 +1,3 @@
+category: "test"
+name: "d"
+version: "1.0"

tests/fixtures/provides_selector/virtual/foo/definition.yaml

@@ -0,0 +1,3 @@
+name: "foo"
+version: "1.1"
+category: "bar"