Require "composer-packages" when composer.json is present (#17)

Co-authored-by: Sophie Wigmore <swigmore@vmware.com>

.gitignore

@@ -2,3 +2,4 @@
 /build
 /bin/
 *.tgz
+.idea/

README.md

@@ -6,11 +6,14 @@ PHP apps.
 
 ## Behavior
 
-This buildpack will always participate if it's `requirements` are met. In the
+This buildpack will always participate if its `requirements` are met. In the
 HTTPD server case `requires` `php`, `php-fpm` optionally, `httpd`, and
 `php-httpd-config`. In the Nginx case, it will require `nginx` and `php-nginx-config`
 instead of `httpd` and `php-httpd-config`.
 
+In either the HTTPD server or Nginx case, this buildpack will require
+`composer-packages` when a `composer.json` file is available.
+
 When this buildpack runs, the `PHP_HTTPD_PATH` OR the `PHP_NGINX_PATH`
 environment variable must be set  by another buildpack in conjunction with
 `PHP_FPM_PATH`. This is because both the HTTPD and Nginx web servers will
@@ -21,12 +24,12 @@ conjunction with the other buildpacks in the Paketo PHP language family.
 Because of this, the usage of this buildpack is fairly tightly coupled to other
 buildpacks in the PHP language family.
 
-
-| Requirement        | Build | Launch |
-|--------------------|-------|--------|
-| `php`              | x     |        |
-| `php-fpm`          | x     | x      |
-| `httpd` or `nginx` | x     |        |
+| Requirement                      | Build | Launch |
+|----------------------------------|-------|--------|
+| `php`                            | x     |        |
+| `composer-packages`              |       | x      |
+| `php-fpm`                        | x     | x      |
+| `httpd` or `nginx`               | x     |        |
 | `httpd-config` or `nginx-config` | x     | x      |
 
 It will set the default start command to something that looks like:

detect.go

@@ -1,7 +1,11 @@
 package phpstart
 
 import (
+	"os"
+	"path/filepath"
+
 	"github.com/paketo-buildpacks/packit/v2"
+	"github.com/paketo-buildpacks/packit/v2/fs"
 )
 
 // BuildPlanMetadata is the buildpack specific data included in build plan
@@ -49,6 +53,23 @@ func Detect() packit.DetectFunc {
 			},
 		}
 
+		composerJsonPath := filepath.Join(context.WorkingDir, "composer.json")
+
+		if value, found := os.LookupEnv("COMPOSER"); found {
+			composerJsonPath = filepath.Join(context.WorkingDir, value)
+		}
+
+		if exists, err := fs.Exists(composerJsonPath); err != nil {
+			return packit.DetectResult{}, err
+		} else if exists {
+			baseRequirements = append(baseRequirements, packit.BuildPlanRequirement{
+				Name: "composer-packages",
+				Metadata: BuildPlanMetadata{
+					Launch: true,
+				},
+			})
+		}
+
 		httpdFpmPlan := packit.BuildPlan{
 			Requires: []packit.BuildPlanRequirement{
 				{

detect_test.go

@@ -2,13 +2,14 @@ package phpstart_test
 
 import (
 	"os"
+	"path/filepath"
 	"testing"
 
+	. "github.com/onsi/gomega"
+	. "github.com/onsi/gomega/gstruct"
 	"github.com/paketo-buildpacks/packit/v2"
 	phpstart "github.com/paketo-buildpacks/php-start"
 	"github.com/sclevine/spec"
-
-	. "github.com/onsi/gomega"
 )
 
 func testDetect(t *testing.T, context spec.G, it spec.S) {
@@ -101,5 +102,71 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 				},
 			}))
 		})
+
+		context("composer", func() {
+			context("with composer.json", func() {
+				it.Before(func() {
+					Expect(os.WriteFile(filepath.Join(workingDir, "composer.json"), []byte(""), os.ModePerm)).To(Succeed())
+				})
+
+				it("requires composer-packages at launch", func() {
+					result, err := detect(packit.DetectContext{
+						WorkingDir: workingDir,
+					})
+					Expect(err).NotTo(HaveOccurred())
+
+					Expect(result.Plan.Requires).To(ContainElements(packit.BuildPlanRequirement{
+						Name: "composer-packages",
+						Metadata: phpstart.BuildPlanMetadata{
+							Launch: true,
+						},
+					}))
+				})
+			})
+
+			context("with $COMPOSER", func() {
+				it.Before(func() {
+					Expect(os.Setenv("COMPOSER", "some/other-file.json")).To(Succeed())
+				})
+
+				it.After(func() {
+					Expect(os.Unsetenv("COMPOSER")).To(Succeed())
+				})
+
+				context("that points to an existing file", func() {
+					it.Before(func() {
+						Expect(os.Mkdir(filepath.Join(workingDir, "some"), os.ModeDir|os.ModePerm)).To(Succeed())
+						Expect(os.WriteFile(filepath.Join(workingDir, "some", "other-file.json"), []byte(""), os.ModePerm)).To(Succeed())
+					})
+
+					it("requires composer-packages at launch", func() {
+						result, err := detect(packit.DetectContext{
+							WorkingDir: workingDir,
+						})
+						Expect(err).NotTo(HaveOccurred())
+
+						Expect(result.Plan.Requires).To(ContainElements(packit.BuildPlanRequirement{
+							Name: "composer-packages",
+							Metadata: phpstart.BuildPlanMetadata{
+								Launch: true,
+							},
+						}))
+					})
+				})
+
+				context("that points to a non existing file", func() {
+					it("does not require composer-packages", func() {
+						result, err := detect(packit.DetectContext{
+							WorkingDir: workingDir,
+						})
+						Expect(err).NotTo(HaveOccurred())
+
+						Expect(result.Plan.Requires).ToNot(ContainElements(MatchFields(IgnoreExtras, Fields{
+							"Name": Equal("composer-packages"),
+						})))
+					})
+				})
+			})
+		}, spec.Sequential())
 	})
 }