Add special case for CFLAGS dir when using Python 3.7 (#703)

Author: thitch97

src/python/supply/supply.go

@@ -284,8 +284,16 @@ func (s *Supplier) InstallPython() error {
 	}
 
 	version := regexp.MustCompile(`\d+\.\d+`).FindString(dep.Version)
-	if err := os.Setenv("CFLAGS", fmt.Sprintf("-I%s", filepath.Join(s.Stager.DepDir(), "python", "include", fmt.Sprintf("python%s", version)))); err != nil {
-		return err
+
+	//Remove once Python 3.7 is out of support (June 2023)
+	if version == "3.7" {
+		if err := os.Setenv("CFLAGS", fmt.Sprintf("-I%s", filepath.Join(s.Stager.DepDir(), "python", "include", fmt.Sprintf("python%sm", version)))); err != nil {
+			return err
+		}
+	} else {
+		if err := os.Setenv("CFLAGS", fmt.Sprintf("-I%s", filepath.Join(s.Stager.DepDir(), "python", "include", fmt.Sprintf("python%s", version)))); err != nil {
+			return err
+		}
 	}
 
 	return nil

src/python/supply/supply_test.go

@@ -95,7 +95,7 @@ var _ = Describe("Supply", func() {
 			pythonInstallDir = filepath.Join(depDir, "python")
 			Expect(os.WriteFile(filepath.Join(depDir, "runtime.txt"), []byte("\n\n\npython-3.4.2\n\n\n"), 0644)).To(Succeed())
 
-			versions = []string{"3.4.2"}
+			versions = []string{"3.4.2", "3.7.13"}
 			originalPath = os.Getenv("PATH")
 		})
 
@@ -116,6 +116,24 @@ var _ = Describe("Supply", func() {
 			})
 		})
 
+		//Remove once Python 3.7 is out of support (June 2023)
+		Context("runtime.txt sets Python version 3.7", func() {
+			BeforeEach(func() {
+				Expect(os.RemoveAll(filepath.Join(depDir, "runtime.txt"))).To(Succeed())
+				Expect(os.WriteFile(filepath.Join(depDir, "runtime.txt"), []byte("\n\n\npython-3.7.13\n\n\n"), 0644)).To(Succeed())
+			})
+			It("installs Python version 3.7", func() {
+				mockManifest.EXPECT().AllDependencyVersions("python").Return(versions)
+				mockInstaller.EXPECT().InstallDependency(libbuildpack.Dependency{Name: "python", Version: "3.7.13"}, pythonInstallDir)
+				mockStager.EXPECT().LinkDirectoryInDepDir(filepath.Join(pythonInstallDir, "bin"), "bin")
+				mockStager.EXPECT().LinkDirectoryInDepDir(filepath.Join(pythonInstallDir, "lib"), "lib")
+				Expect(supplier.InstallPython()).To(Succeed())
+				Expect(os.Getenv("PATH")).To(Equal(fmt.Sprintf("%s:%s", filepath.Join(depDir, "bin"), originalPath)))
+				Expect(os.Getenv("PYTHONPATH")).To(Equal(depDir))
+				Expect(os.Getenv("CFLAGS")).To(Equal(fmt.Sprintf("-I%s", filepath.Join(depDir, "python", "include", "python3.7m"))))
+			})
+		})
+
 		Context("no runtime.txt is provided", func() {
 			BeforeEach(func() {
 				Expect(os.RemoveAll(filepath.Join(depDir, "runtime.txt"))).To(Succeed())