Add support for PEP 621 for specifying Python version (#503)

* Add support for PEP 621 for specifying Python version

Author: TheSuperiorStanislav

.gitignore

@@ -1,6 +1,7 @@
 .DS_Store
 !integration/testdata
 .bin
+bin
 build
 .idea/
 linux

detect.go

@@ -39,7 +39,7 @@ func Detect(parser PyProjectPythonVersionParser) packit.DetectFunc {
 		}
 
 		if pythonVersion == "" {
-			return packit.DetectResult{}, packit.Fail.WithMessage("%s must include [tool.poetry.dependencies.python], see https://python-poetry.org/docs/pyproject/#dependencies-and-dev-dependencies", PyProjectTomlFile)
+			return packit.DetectResult{}, packit.Fail.WithMessage("%s must include [project.requires-python] or [tool.poetry.dependencies.python], see https://python-poetry.org/docs/pyproject/#requires-python", PyProjectTomlFile)
 		}
 
 		requirements := []packit.BuildPlanRequirement{

detect_test.go

@@ -141,7 +141,7 @@ func testDetect(t *testing.T, context spec.G, it spec.S) {
 				_, err := detect(packit.DetectContext{
 					WorkingDir: workingDir,
 				})
-				Expect(err).To(MatchError(packit.Fail.WithMessage("pyproject.toml must include [tool.poetry.dependencies.python], see https://python-poetry.org/docs/pyproject/#dependencies-and-dev-dependencies")))
+				Expect(err).To(MatchError(packit.Fail.WithMessage("pyproject.toml must include [project.requires-python] or [tool.poetry.dependencies.python], see https://python-poetry.org/docs/pyproject/#requires-python")))
 			})
 		})
 

integration/default_test.go

@@ -93,12 +93,75 @@ func testDefault(t *testing.T, context spec.G, it spec.S) {
 			Expect(logs).To(ContainLines(
 				"  Resolving CPython version",
 				"    Candidate version sources (in priority order):",
-				`      pyproject.toml -> "3.9.*"`,
+				`      pyproject.toml -> "3.13.*"`,
 				`                     -> ""`,
 				`      <unknown>      -> ""`,
 			))
 			Expect(logs).To(ContainLines(
-				MatchRegexp(`\s*Python version \(using pyproject.toml\): 3\.9\.\d+`),
+				MatchRegexp(`\s*Python version \(using pyproject.toml\): 3\.13\.\d+`),
+			))
+
+			container, err = docker.Container.Run.
+				WithCommand("poetry --version").
+				Execute(image.ID)
+			Expect(err).ToNot(HaveOccurred())
+
+			Eventually(func() string {
+				cLogs, err := docker.Container.Logs.Execute(container.ID)
+				Expect(err).NotTo(HaveOccurred())
+				return cLogs.String()
+			}).Should(MatchRegexp(`Poetry.*version \d+\.\d+\.\d+`))
+		})
+
+		it("builds with the poetry v1 pyproject.toml", func() {
+			var err error
+			var logs fmt.Stringer
+
+			source, err = occam.Source(filepath.Join("testdata", "poetry_v1"))
+			Expect(err).NotTo(HaveOccurred())
+
+			image, logs, err = pack.WithNoColor().Build.
+				WithPullPolicy("never").
+				WithBuildpacks(
+					settings.Buildpacks.CPython.Online,
+					settings.Buildpacks.Pip.Online,
+					settings.Buildpacks.Poetry.Online,
+					settings.Buildpacks.BuildPlan.Online,
+				).
+				Execute(name, source)
+			Expect(err).ToNot(HaveOccurred(), logs.String)
+
+			Expect(logs).To(ContainLines(
+				MatchRegexp(fmt.Sprintf(`%s \d+\.\d+\.\d+`, buildpackInfo.Buildpack.Name)),
+				"  Resolving Poetry version",
+				"    Candidate version sources (in priority order):",
+				`      <unknown> -> ""`,
+			))
+			Expect(logs).To(ContainLines(
+				MatchRegexp(`    Selected Poetry version \(using <unknown>\): \d+\.\d+\.\d+`),
+			))
+			Expect(logs).To(ContainLines(
+				"  Executing build process",
+				MatchRegexp(`    Installing Poetry \d+\.\d+\.\d+`),
+				MatchRegexp(`      Completed in \d+\.\d+`),
+			))
+			Expect(logs).To(ContainLines(
+				"  Configuring build environment",
+				MatchRegexp(fmt.Sprintf(`    PYTHONPATH -> "\/layers\/%s\/poetry\/lib\/python\d+\.\d+\/site-packages:\$PYTHONPATH"`, strings.ReplaceAll(buildpackInfo.Buildpack.ID, "/", "_"))),
+				"",
+				"  Configuring launch environment",
+				MatchRegexp(fmt.Sprintf(`    PYTHONPATH -> "\/layers\/%s\/poetry\/lib\/python\d+\.\d+\/site-packages:\$PYTHONPATH"`, strings.ReplaceAll(buildpackInfo.Buildpack.ID, "/", "_"))),
+			))
+
+			Expect(logs).To(ContainLines(
+				"  Resolving CPython version",
+				"    Candidate version sources (in priority order):",
+				`      pyproject.toml -> "3.12.*"`,
+				`                     -> ""`,
+				`      <unknown>      -> ""`,
+			))
+			Expect(logs).To(ContainLines(
+				MatchRegexp(`\s*Python version \(using pyproject.toml\): 3\.12\.\d+`),
 			))
 
 			container, err = docker.Container.Run.

integration/testdata/default_app/pyproject.toml

@@ -1,2 +1,4 @@
-[tool.poetry.dependencies]
-python = "3.9.*"
+[project]
+name = "integration-test"
+version = "0.0.0"
+requires-python = "3.13.*"

integration/testdata/poetry_v1/plan.toml

@@ -0,0 +1,11 @@
+[[requires]]
+name = "poetry"
+
+[requires.metadata]
+launch = true
+
+[[requires]]
+name = "cpython"
+
+[requires.metadata]
+launch = true

integration/testdata/poetry_v1/pyproject.toml

@@ -0,0 +1,2 @@
+[tool.poetry.dependencies]
+python = "3.12.*"

pyproject_parser.go

@@ -12,6 +12,9 @@ type PyProjectToml struct {
 			}
 		}
 	}
+	Project struct {
+		RequiresPython string `toml:"requires-python"`
+	}
 }
 
 type PyProjectParser struct {
@@ -29,5 +32,8 @@ func (p PyProjectParser) ParsePythonVersion(pyProjectToml string) (string, error
 		return "", err
 	}
 
+	if pyProject.Project.RequiresPython != "" {
+		return pyProject.Project.RequiresPython, nil
+	}
 	return pyProject.Tool.Poetry.Dependencies.Python, nil
 }

pyproject_parser_test.go

@@ -23,6 +23,8 @@ func testPyProjectParser(t *testing.T, context spec.G, it spec.S) {
 	const (
 		version = `[tool.poetry.dependencies]
 python = "===1.2.3"`
+		version_pep621 = `[project]
+requires-python = ">=1.2.3"`
 	)
 
 	it.Before(func() {
@@ -48,7 +50,15 @@ python = "===1.2.3"`
 			Expect(version).To(Equal("===1.2.3"))
 		})
 
-		it("returns empty string if file does not contain 'tool.poetry.dependencies.python'", func() {
+		it("parses version PEP621", func() {
+			Expect(os.WriteFile(pyProjectToml, []byte(version_pep621), 0644)).To(Succeed())
+
+			version, err := parser.ParsePythonVersion(pyProjectToml)
+			Expect(err).NotTo(HaveOccurred())
+			Expect(version).To(Equal(">=1.2.3"))
+		})
+
+		it("returns empty string if file does not contain 'tool.poetry.dependencies.python' or project.requires-python", func() {
 			Expect(os.WriteFile(pyProjectToml, []byte(""), 0644)).To(Succeed())
 
 			version, err := parser.ParsePythonVersion(pyProjectToml)