Pip: Do not create a virtual environment

As no dependencies are installed anymore there is no need to create a
virtual environment. The Python binary from the path is now used to get
metadata from setup.py. This might temporarily cause issues if the
setup.py is not compatible with this Python version, but this will soon
be fixed once this data can be retrieved from the python-inspector
output (this will be available once [1] is released).

[1]: aboutcode-org/python-inspector#69

Signed-off-by: Martin Nonnenmacher <[email protected]>

Author: mnonnenmacher

analyzer/src/main/kotlin/managers/Pip.kt

@@ -19,8 +19,6 @@
 
 package org.ossreviewtoolkit.analyzer.managers
 
-import com.vdurmont.semver4j.Requirement
-
 import java.io.File
 import java.util.SortedSet
 
@@ -44,76 +42,14 @@ import org.ossreviewtoolkit.model.config.PackageManagerConfiguration
 import org.ossreviewtoolkit.model.config.RepositoryConfiguration
 import org.ossreviewtoolkit.utils.common.CommandLineTool
 import org.ossreviewtoolkit.utils.common.Os
-import org.ossreviewtoolkit.utils.common.ProcessCapture
 import org.ossreviewtoolkit.utils.common.collectMessages
 import org.ossreviewtoolkit.utils.common.safeDeleteRecursively
-import org.ossreviewtoolkit.utils.ort.createOrtTempDir
-import org.ossreviewtoolkit.utils.ort.createOrtTempFile
 import org.ossreviewtoolkit.utils.ort.showStackTrace
 
-object VirtualEnv : CommandLineTool {
-    override fun command(workingDir: File?) = "virtualenv"
-
-    override fun transformVersion(output: String) =
-        // The version string can be something like:
-        // 16.6.1
-        // virtualenv 20.0.14 from /usr/local/lib/python2.7/dist-packages/virtualenv/__init__.pyc
-        output.removePrefix("virtualenv ").substringBefore(' ')
-
-    // Ensure a minimum version known to work. Note that virtualenv bundles a version of pip, and as of pip 20.3 a new
-    // dependency resolver is used, see http://pyfound.blogspot.com/2020/11/pip-20-3-new-resolver.html.
-    override fun getVersionRequirement(): Requirement = Requirement.buildIvy("[15.1,)")
-}
-
-object PythonVersion : CommandLineTool, Logging {
-    // To use a specific version of Python on Windows we can use the "py" command with argument "-2" or "-3", see
-    // https://docs.python.org/3/installing/#work-with-multiple-versions-of-python-installed-in-parallel.
+object Python : CommandLineTool, Logging {
     override fun command(workingDir: File?) = if (Os.isWindows) "py" else "python3"
 
     override fun transformVersion(output: String) = output.removePrefix("Python ")
-
-    /**
-     * Check all Python files in [workingDir] and return which version of Python they are compatible with. If all files
-     * are compatible with Python 3, "3" is returned. If at least one file is incompatible with Python 3, "2" is
-     * returned.
-     */
-    fun getPythonMajorVersion(workingDir: File): Int {
-        val scriptFile = createOrtTempFile("python_compatibility", ".py")
-        scriptFile.writeBytes(javaClass.getResource("/scripts/python_compatibility.py").readBytes())
-
-        try {
-            // The helper script itself always has to be run with Python 3.
-            val scriptCmd = if (Os.isWindows) {
-                run("-3", scriptFile.path, "-d", workingDir.path)
-            } else {
-                run(scriptFile.path, "-d", workingDir.path)
-            }
-
-            return scriptCmd.stdout.toInt()
-        } finally {
-            if (!scriptFile.delete()) {
-                logger.warn { "Helper script file '$scriptFile' could not be deleted." }
-            }
-        }
-    }
-
-    /**
-     * Return the absolute path to the Python interpreter for the given [version]. This is helpful as esp. on Windows
-     * different Python versions can be installed in arbitrary locations, and the Python executable is even usually
-     * called the same in those locations. Return `null` if no matching Python interpreter is available.
-     */
-    fun getPythonInterpreter(version: Int): String? =
-        if (Os.isWindows) {
-            val installedVersions = run("--list-paths").stdout
-            val versionAndPath = installedVersions.lines().find { line ->
-                line.startsWith(" -$version")
-            }
-
-            // Parse a line like " -2.7-32        C:\Python27\python.exe".
-            versionAndPath?.split(' ', limit = 3)?.last()?.trimStart()
-        } else {
-            Os.getPathFromEnvironment("python$version")?.path
-        }
 }
 
 private const val OPTION_OPERATING_SYSTEM = "operatingSystem"
@@ -173,52 +109,23 @@ class Pip(
 
     override fun transformVersion(output: String) = output.removePrefix("pip ").substringBefore(' ')
 
-    private fun runInVirtualEnv(
-        virtualEnvDir: File,
-        workingDir: File,
-        commandName: String,
-        vararg commandArgs: String
-    ): ProcessCapture {
-        val binDir = if (Os.isWindows) "Scripts" else "bin"
-        val command = virtualEnvDir.resolve(binDir).resolve(commandName)
-        val resolvedCommand = Os.resolveWindowsExecutable(command)?.takeIf { Os.isWindows } ?: command
-
-        // TODO: Maybe work around long shebang paths in generated scripts within a virtualenv by calling the Python
-        //       executable in the virtualenv directly, see https://github.com/pypa/virtualenv/issues/997.
-        val process = ProcessCapture(workingDir, resolvedCommand.path, *commandArgs)
-        logger.debug { process.stdout }
-        return process
-    }
-
-    override fun beforeResolution(definitionFiles: List<File>) = VirtualEnv.checkVersion()
-
     override fun resolveDependencies(definitionFile: File, labels: Map<String, String>): List<ProjectAnalyzerResult> {
         // For an overview, dependency resolution involves the following steps:
         // 1. Get metadata about the local project via `python setup.py`.
         // 2. Get the dependency tree and dependency metadata via python-inspector.
 
-        val workingDir = definitionFile.parentFile
-
-        // Try to determine the Python version the project requires.
-        val pythonMajorVersion = PythonVersion.getPythonMajorVersion(workingDir)
-
-        val virtualEnvDir = setupVirtualEnv(workingDir, pythonMajorVersion)
-
-        val project = getProjectBasics(definitionFile, virtualEnvDir)
+        val project = getProjectBasics(definitionFile)
         val (packages, installDependencies) = getInstallDependencies(definitionFile)
 
         // TODO: Handle "extras" and "tests" dependencies.
         val scopes = sortedSetOf(
             Scope("install", installDependencies)
         )
 
-        // Remove the virtualenv by simply deleting the directory.
-        virtualEnvDir.safeDeleteRecursively()
-
         return listOf(ProjectAnalyzerResult(project.copy(scopeDependencies = scopes), packages))
     }
 
-    private fun getProjectBasics(definitionFile: File, virtualEnvDir: File): Project {
+    private fun getProjectBasics(definitionFile: File): Project {
         val authors = sortedSetOf<String>()
         val declaredLicenses = sortedSetOf<String>()
 
@@ -228,7 +135,7 @@ class Pip(
         val (setupName, setupVersion, setupHomepage) = if (workingDir.resolve("setup.py").isFile) {
             // See https://docs.python.org/3.8/distutils/setupscript.html#additional-meta-data.
             fun getSetupPyMetadata(option: String): String? {
-                val process = runInVirtualEnv(virtualEnvDir, workingDir, "python", "setup.py", option)
+                val process = Python.run(workingDir, "setup.py", option)
                 val metadata = process.stdout.trim()
                 return metadata.takeUnless { process.isError || metadata == "UNKNOWN" }
             }
@@ -362,18 +269,4 @@ class Pip(
         val license = classifiers.takeIf { it.first() in licenseClassifiers }?.last()
         return license?.takeUnless { it in licenseClassifiers }
     }
-
-    private fun setupVirtualEnv(workingDir: File, pythonMajorVersion: Int): File {
-        // Create an out-of-tree virtualenv.
-        logger.info { "Creating a virtualenv for the '${workingDir.name}' project directory..." }
-
-        val virtualEnvDir = createOrtTempDir("${workingDir.name}-virtualenv")
-        val pythonInterpreter = requireNotNull(PythonVersion.getPythonInterpreter(pythonMajorVersion)) {
-            "No Python interpreter found for version $pythonMajorVersion."
-        }
-
-        ProcessCapture(workingDir, "virtualenv", virtualEnvDir.path, "-p", pythonInterpreter).requireSuccess()
-
-        return virtualEnvDir
-    }
 }