src/eric7/PipInterface/Pip.py

# -*- coding: utf-8 -*-

# Copyright (c) 2015 - 2023 Detlev Offenbach <detlev@die-offenbachs.de>
#

"""
Package implementing the pip GUI logic.
"""

import contextlib
import functools
import json
import os
import sys

from PyQt6.QtCore import QCoreApplication, QObject, QProcess, QThread, QUrl, pyqtSlot
from PyQt6.QtNetwork import QNetworkAccessManager, QNetworkReply, QNetworkRequest
from PyQt6.QtWidgets import QDialog, QInputDialog, QLineEdit

from eric7 import Preferences
from eric7.EricNetwork.EricNetworkProxyFactory import proxyAuthenticationRequired
from eric7.EricWidgets import EricMessageBox
from eric7.EricWidgets.EricApplication import ericApp
from eric7.SystemUtilities import OSUtilities, PythonUtilities
from eric7.UI.DeleteFilesConfirmationDialog import DeleteFilesConfirmationDialog

try:
    from eric7.EricNetwork.EricSslErrorHandler import EricSslErrorHandler

    SSL_AVAILABLE = True
except ImportError:
    SSL_AVAILABLE = False

from .PipDialog import PipDialog
from .PipVulnerabilityChecker import PipVulnerabilityChecker


class Pip(QObject):
    """
    Class implementing the pip GUI logic.
    """

    DefaultPyPiUrl = "https://pypi.org"
    DefaultIndexUrlPypi = DefaultPyPiUrl + "/pypi"
    DefaultIndexUrlSimple = DefaultPyPiUrl + "/simple"
    DefaultIndexUrlSearch = DefaultPyPiUrl + "/search/"

    def __init__(self, parent=None):
        """
        Constructor

        @param parent reference to the user interface object
        @type QObject
        """
        super().__init__(parent)

        self.__ui = parent

        # attributes for the network objects
        self.__networkManager = QNetworkAccessManager(self)
        self.__networkManager.proxyAuthenticationRequired.connect(
            proxyAuthenticationRequired
        )
        if SSL_AVAILABLE:
            self.__sslErrorHandler = EricSslErrorHandler(self)
            self.__networkManager.sslErrors.connect(
                self.__sslErrorHandler.sslErrorsReply
            )
        self.__replies = []

        self.__vulnerabilityChecker = PipVulnerabilityChecker(self, self)

    def getNetworkAccessManager(self):
        """
        Public method to get a reference to the network access manager object.

        @return reference to the network access manager object
        @rtype QNetworkAccessManager
        """
        return self.__networkManager

    def getVulnerabilityChecker(self):
        """
        Public method to get a reference to the vulnerability checker object.

        @return reference to the vulnerability checker object
        @rtype PipVulnerabilityChecker
        """
        return self.__vulnerabilityChecker

    ##########################################################################
    ## Methods below implement some utility functions
    ##########################################################################

    def runProcess(self, args, interpreter):
        """
        Public method to execute the current pip with the given arguments.

        The selected pip executable is called with the given arguments and
        waited for its end.

        @param args list of command line arguments
        @type list of str
        @param interpreter path of the Python interpreter to be used
        @type str
        @return tuple containing a flag indicating success and the output
            of the process
        @rtype tuple of (bool, str)
        """
        ioEncoding = Preferences.getSystem("IOEncoding")

        process = QProcess()
        process.start(interpreter, args)
        procStarted = process.waitForStarted()
        if procStarted:
            finished = process.waitForFinished(30000)
            if finished:
                if process.exitCode() == 0:
                    output = str(process.readAllStandardOutput(), ioEncoding, "replace")
                    return True, output
                else:
                    return (
                        False,
                        self.tr("python exited with an error ({0}).").format(
                            process.exitCode()
                        ),
                    )
            else:
                process.terminate()
                process.waitForFinished(2000)
                process.kill()
                process.waitForFinished(3000)
                return False, self.tr("python did not finish within" " 30 seconds.")

        return False, self.tr("python could not be started.")

    def getUserConfig(self):
        """
        Public method to get the name of the user configuration file.

        @return path of the user configuration file
        @rtype str
        """
        # Unix:     ~/.config/pip/pip.conf
        # OS X:     ~/Library/Application Support/pip/pip.conf
        # Windows:  %APPDATA%\pip\pip.ini
        # Environment: $PIP_CONFIG_FILE

        with contextlib.suppress(KeyError):
            return os.environ["PIP_CONFIG_FILE"]

        if OSUtilities.isWindowsPlatform():
            config = os.path.join(os.environ["APPDATA"], "pip", "pip.ini")
        elif OSUtilities.isMacPlatform():
            config = os.path.expanduser("~/Library/Application Support/pip/pip.conf")
        else:
            config = os.path.expanduser("~/.config/pip/pip.conf")

        return config

    def getVirtualenvConfig(self, venvName):
        """
        Public method to get the name of the virtualenv configuration file.

        @param venvName name of the environment to get config file path for
        @type str
        @return path of the virtualenv configuration file
        @rtype str
        """
        # Unix, OS X:   $VIRTUAL_ENV/pip.conf
        # Windows:      %VIRTUAL_ENV%\pip.ini

        pip = "pip.ini" if OSUtilities.isWindowsPlatform() else "pip.conf"

        venvManager = ericApp().getObject("VirtualEnvManager")
        venvDirectory = (
            os.path.dirname(self.getUserConfig())
            if venvManager.isGlobalEnvironment(venvName)
            else venvManager.getVirtualenvDirectory(venvName)
        )

        config = os.path.join(venvDirectory, pip) if venvDirectory else ""

        return config

    def getProjectEnvironmentString(self):
        """
        Public method to get the string for the project environment.

        @return string for the project environment
        @rtype str
        """
        try:
            project = ericApp().getObject("Project")
            if project.isOpen():
                return self.tr("<project>")
            else:
                return ""
        except KeyError:
            return ""

    def getVirtualenvInterpreter(self, venvName):
        """
        Public method to get the interpreter for a virtual environment.

        @param venvName logical name for the virtual environment
        @type str
        @return interpreter path
        @rtype str
        """
        interpreter = (
            ericApp().getObject("Project").getProjectInterpreter()
            if venvName in (self.getProjectEnvironmentString(), "<project>")
            else ericApp()
            .getObject("VirtualEnvManager")
            .getVirtualenvInterpreter(venvName)
        )
        if not interpreter:
            EricMessageBox.critical(
                None,
                self.tr("Interpreter for Virtual Environment"),
                self.tr(
                    """No interpreter configured for the selected"""
                    """ virtual environment."""
                ),
            )

        return interpreter

    def getVirtualenvNames(self, noRemote=False, noConda=False):
        """
        Public method to get a sorted list of virtual environment names.

        @param noRemote flag indicating to exclude environments for remote
            debugging
        @type bool
        @param noConda flag indicating to exclude Conda environments
        @type bool
        @return sorted list of virtual environment names
        @rtype list of str
        """
        return sorted(
            ericApp()
            .getObject("VirtualEnvManager")
            .getVirtualenvNames(noRemote=noRemote, noConda=noConda)
        )

    def installPip(self, venvName, userSite=False):
        """
        Public method to install pip.

        @param venvName name of the environment to install pip into
        @type str
        @param userSite flag indicating an install to the user install
            directory
        @type bool
        """
        interpreter = self.getVirtualenvInterpreter(venvName)
        if not interpreter:
            return

        dia = PipDialog(self.tr("Install PIP"))
        commands = (
            [(interpreter, ["-m", "ensurepip", "--user"])]
            if userSite
            else [(interpreter, ["-m", "ensurepip"])]
        )
        if Preferences.getPip("PipSearchIndex"):
            indexUrl = Preferences.getPip("PipSearchIndex") + "/simple"
            args = ["-m", "pip", "install", "--index-url", indexUrl, "--upgrade"]
        else:
            args = ["-m", "pip", "install", "--upgrade"]
        if userSite:
            args.append("--user")
        args.append("pip")
        commands.append((interpreter, args[:]))

        res = dia.startProcesses(commands)
        if res:
            dia.exec()

    @pyqtSlot()
    def repairPip(self, venvName):
        """
        Public method to repair the pip installation.

        @param venvName name of the environment to install pip into
        @type str
        """
        interpreter = self.getVirtualenvInterpreter(venvName)
        if not interpreter:
            return

        # python -m pip install --ignore-installed pip
        if Preferences.getPip("PipSearchIndex"):
            indexUrl = Preferences.getPip("PipSearchIndex") + "/simple"
            args = [
                "-m",
                "pip",
                "install",
                "--index-url",
                indexUrl,
                "--ignore-installed",
            ]
        else:
            args = ["-m", "pip", "install", "--ignore-installed"]
        args.append("pip")

        dia = PipDialog(self.tr("Repair PIP"))
        res = dia.startProcess(interpreter, args)
        if res:
            dia.exec()

    def __checkUpgradePyQt(self, packages):
        """
        Private method to check, if an upgrade of PyQt packages is attempted.

        @param packages list of packages to upgrade
        @type list of str
        @return flag indicating a PyQt upgrade
        @rtype bool
        """
        pyqtPackages = [
            p
            for p in packages
            if p.lower()
            in [
                "pyqt6",
                "pyqt6-sip",
                "pyqt6-webengine",
                "pyqt6-charts",
                "pyqt6-qscintilla",
                "pyqt6-qt6",
                "pyqt6-webengine-qt6",
                "pyqt6-charts-qt6",
            ]
        ]
        return bool(pyqtPackages)

    def __checkUpgradeEric(self, packages):
        """
        Private method to check, if an upgrade of the eric-ide package is
        attempted.

        @param packages list of packages to upgrade
        @type list of str
        @return flag indicating an eric-ide upgrade
        @rtype bool
        """
        ericPackages = [p for p in packages if p.lower() == "eric-ide"]
        return bool(ericPackages)

    def upgradePackages(self, packages, venvName, userSite=False):
        """
        Public method to upgrade the given list of packages.

        @param packages list of packages to upgrade
        @type list of str
        @param venvName name of the virtual environment to be used
        @type str
        @param userSite flag indicating an install to the user install
            directory
        @type bool
        @return flag indicating a successful execution
        @rtype bool
        """
        if not venvName:
            return False

        if self.getVirtualenvInterpreter(venvName) in (
            sys.executable,
            PythonUtilities.getPythonExecutable(),
        ):
            upgradePyQt = self.__checkUpgradePyQt(packages)
            upgradeEric = self.__checkUpgradeEric(packages)
            if upgradeEric or upgradePyQt:
                try:
                    if upgradeEric and upgradePyQt:
                        self.__ui.upgradeEricPyQt()
                    elif upgradeEric:
                        self.__ui.upgradeEric()
                    elif upgradePyQt:
                        self.__ui.upgradePyQt()
                    return None  # should not be reached; play it safe
                except AttributeError:
                    return False

        interpreter = self.getVirtualenvInterpreter(venvName)
        if not interpreter:
            return False

        if Preferences.getPip("PipSearchIndex"):
            indexUrl = Preferences.getPip("PipSearchIndex") + "/simple"
            args = ["-m", "pip", "install", "--index-url", indexUrl, "--upgrade"]
        else:
            args = ["-m", "pip", "install", "--upgrade"]
        if userSite:
            args.append("--user")
        args += packages
        dia = PipDialog(self.tr("Upgrade Packages"))
        res = dia.startProcess(interpreter, args)
        if res:
            dia.exec()
        return res

    def installPackages(
        self,
        packages,
        venvName="",
        userSite=False,
        interpreter="",
        forceReinstall=False,
    ):
        """
        Public method to install the given list of packages.

        @param packages list of packages to install
        @type list of str
        @param venvName name of the virtual environment to be used
        @type str
        @param userSite flag indicating an install to the user install
            directory
        @type bool
        @param interpreter interpreter to be used for execution
        @type str
        @param forceReinstall flag indicating to force a reinstall of
            the packages
        @type bool
        """
        if venvName:
            interpreter = self.getVirtualenvInterpreter(venvName)
            if not interpreter:
                return

        if interpreter:
            if Preferences.getPip("PipSearchIndex"):
                indexUrl = Preferences.getPip("PipSearchIndex") + "/simple"
                args = ["-m", "pip", "install", "--index-url", indexUrl]
            else:
                args = ["-m", "pip", "install"]
            if userSite:
                args.append("--user")
            if forceReinstall:
                args.append("--force-reinstall")
            args += packages
            dia = PipDialog(self.tr("Install Packages"))
            res = dia.startProcess(interpreter, args)
            if res:
                dia.exec()

    def installRequirements(self, venvName):
        """
        Public method to install packages as given in a requirements file.

        @param venvName name of the virtual environment to be used
        @type str
        """
        from .PipFileSelectionDialog import PipFileSelectionDialog

        dlg = PipFileSelectionDialog(self, "requirements")
        if dlg.exec() == QDialog.DialogCode.Accepted:
            requirements, user = dlg.getData()
            if requirements and os.path.exists(requirements):
                interpreter = self.getVirtualenvInterpreter(venvName)
                if not interpreter:
                    return

                if Preferences.getPip("PipSearchIndex"):
                    indexUrl = Preferences.getPip("PipSearchIndex") + "/simple"
                    args = ["-m", "pip", "install", "--index-url", indexUrl]
                else:
                    args = ["-m", "pip", "install"]
                if user:
                    args.append("--user")
                args += ["--requirement", requirements]
                dia = PipDialog(self.tr("Install Packages from Requirements"))
                res = dia.startProcess(interpreter, args)
                if res:
                    dia.exec()

    def installEditableProject(self, interpreter, projectPath):
        """
        Public method to install a project in development mode.

        @param interpreter interpreter to be used for execution
        @type str
        @param projectPath path of the project
        @type str
        """
        if interpreter and projectPath:
            args = ["-m", "pip", "install"]
            if Preferences.getPip("PipSearchIndex"):
                indexUrl = Preferences.getPip("PipSearchIndex") + "/simple"
                args += ["--index-url", indexUrl]
            args += ["--editable", projectPath]

            dia = PipDialog(self.tr("Install Project"))
            res = dia.startProcess(interpreter, args)
            if res:
                dia.exec()

    def uninstallPackages(self, packages, venvName):
        """
        Public method to uninstall the given list of packages.

        @param packages list of packages to uninstall
        @type list of str
        @param venvName name of the virtual environment to be used
        @type str
        @return flag indicating a successful execution
        @rtype bool
        """
        res = False
        if packages and venvName:
            dlg = DeleteFilesConfirmationDialog(
                self.parent(),
                self.tr("Uninstall Packages"),
                self.tr("Do you really want to uninstall these packages?"),
                packages,
            )
            if dlg.exec() == QDialog.DialogCode.Accepted:
                interpreter = self.getVirtualenvInterpreter(venvName)
                if not interpreter:
                    return False
                args = ["-m", "pip", "uninstall", "--yes"] + packages
                dia = PipDialog(self.tr("Uninstall Packages"))
                res = dia.startProcess(interpreter, args)
                if res:
                    dia.exec()
        return res

    def uninstallRequirements(self, venvName):
        """
        Public method to uninstall packages as given in a requirements file.

        @param venvName name of the virtual environment to be used
        @type str
        """
        from .PipFileSelectionDialog import PipFileSelectionDialog

        if venvName:
            dlg = PipFileSelectionDialog(self, "requirements", install=False)
            if dlg.exec() == QDialog.DialogCode.Accepted:
                requirements, _user = dlg.getData()
                if requirements and os.path.exists(requirements):
                    try:
                        with open(requirements, "r") as f:
                            reqs = f.read().splitlines()
                    except OSError:
                        return

                    dlg = DeleteFilesConfirmationDialog(
                        self.parent(),
                        self.tr("Uninstall Packages"),
                        self.tr("Do you really want to uninstall these packages?"),
                        reqs,
                    )
                    if dlg.exec() == QDialog.DialogCode.Accepted:
                        interpreter = self.getVirtualenvInterpreter(venvName)
                        if not interpreter:
                            return

                        args = ["-m", "pip", "uninstall", "--requirement", requirements]
                        dia = PipDialog(self.tr("Uninstall Packages from Requirements"))
                        res = dia.startProcess(interpreter, args)
                        if res:
                            dia.exec()

    def getIndexUrl(self):
        """
        Public method to get the index URL for PyPI.

        @return index URL for PyPI
        @rtype str
        """
        indexUrl = (
            Preferences.getPip("PipSearchIndex") + "/simple"
            if Preferences.getPip("PipSearchIndex")
            else Pip.DefaultIndexUrlSimple
        )

        return indexUrl

    def getIndexUrlPypi(self):
        """
        Public method to get the index URL for PyPI API calls.

        @return index URL for XML RPC calls
        @rtype str
        """
        indexUrl = (
            Preferences.getPip("PipSearchIndex") + "/pypi"
            if Preferences.getPip("PipSearchIndex")
            else Pip.DefaultIndexUrlPypi
        )

        return indexUrl

    def getIndexUrlSearch(self):
        """
        Public method to get the index URL for PyPI API calls.

        @return index URL for XML RPC calls
        @rtype str
        """
        indexUrl = (
            Preferences.getPip("PipSearchIndex") + "/search/"
            if Preferences.getPip("PipSearchIndex")
            else Pip.DefaultIndexUrlSearch
        )

        return indexUrl

    def getInstalledPackages(
        self, envName, localPackages=True, notRequired=False, usersite=False
    ):
        """
        Public method to get the list of installed packages.

        @param envName name of the environment to get the packages for
        @type str
        @param localPackages flag indicating to get local packages only
        @type bool
        @param notRequired flag indicating to list packages that are not
            dependencies of installed packages as well
        @type bool
        @param usersite flag indicating to only list packages installed
            in user-site
        @type bool
        @return list of tuples containing the package name and version
        @rtype list of tuple of (str, str)
        """
        packages = []

        if envName:
            interpreter = self.getVirtualenvInterpreter(envName)
            if interpreter:
                args = [
                    "-m",
                    "pip",
                    "list",
                    "--format=json",
                ]
                if localPackages:
                    args.append("--local")
                if notRequired:
                    args.append("--not-required")
                if usersite:
                    args.append("--user")

                if Preferences.getPip("PipSearchIndex"):
                    indexUrl = Preferences.getPip("PipSearchIndex") + "/simple"
                    args += ["--index-url", indexUrl]

                proc = QProcess()
                proc.start(interpreter, args)
                if proc.waitForStarted(15000) and proc.waitForFinished(30000):
                    output = str(
                        proc.readAllStandardOutput(),
                        Preferences.getSystem("IOEncoding"),
                        "replace",
                    ).strip()
                    if output:
                        output = output.splitlines()[0]
                        try:
                            jsonList = json.loads(output)
                        except Exception:
                            jsonList = []

                        for package in jsonList:
                            if isinstance(package, dict):
                                packages.append(
                                    (
                                        package["name"],
                                        package["version"],
                                    )
                                )

        return packages

    def getOutdatedPackages(
        self,
        envName,
        localPackages=True,
        notRequired=False,
        usersite=False,
        interpreter=None,
        callback=None,
    ):
        """
        Public method to get the list of outdated packages.

        @param envName name of the environment to get the packages for
        @type str
        @param localPackages flag indicating to get local packages only
            (defaults to False)
        @type bool (optional)
        @param notRequired flag indicating to list packages that are not
            dependencies of installed packages as well (defaults to False)
        @type bool (optional)
        @param usersite flag indicating to only list packages installed
            in user-site (defaults to False)
        @type bool (optional)
        @param interpreter path of an interpreter executable. If this is not
            None, it will override the given environment name (defaults to None)
        @type str (optional)
        @param callback method accepting a list of tuples containing the
            package name, installed version and available version
        @type function
        @return list of tuples containing the package name, installed version
            and available version
        @rtype list of tuple of (str, str, str)
        """
        packages = []

        if envName:
            if interpreter is None:
                interpreter = self.getVirtualenvInterpreter(envName)
            if interpreter:
                args = [
                    "-m",
                    "pip",
                    "list",
                    "--outdated",
                    "--format=json",
                ]
                if localPackages:
                    args.append("--local")
                if notRequired:
                    args.append("--not-required")
                if usersite:
                    args.append("--user")

                if Preferences.getPip("PipSearchIndex"):
                    indexUrl = Preferences.getPip("PipSearchIndex") + "/simple"
                    args += ["--index-url", indexUrl]

                proc = QProcess()
                if callback:
                    self.__outdatedProc = proc
                    proc.finished.connect(
                        functools.partial(self.__outdatedFinished, callback, proc)
                    )
                    proc.start(interpreter, args)
                    return None

                proc.start(interpreter, args)
                if proc.waitForStarted(15000) and proc.waitForFinished(30000):
                    packages = self.__extractOutdatedPackages(proc)

        return packages

    def __extractOutdatedPackages(self, proc):
        """
        Private method to extract the outdated packages list out of the process output.

        @param proc reference to the process
        @type QProcess
        @return list of tuples containing the package name, installed version
            and available version
        @rtype list of tuple of (str, str, str)
        """
        packages = []

        output = str(
            proc.readAllStandardOutput(),
            Preferences.getSystem("IOEncoding"),
            "replace",
        ).strip()
        if output:
            output = output.splitlines()[0]
            try:
                jsonList = json.loads(output)
            except Exception:
                jsonList = []

            for package in jsonList:
                if isinstance(package, dict):
                    packages.append(
                        (
                            package["name"],
                            package["version"],
                            package["latest_version"],
                        )
                    )

        return packages

    def __outdatedFinished(self, callback, proc, exitCode, exitStatus):
        """
        Private method to handle the process finished signal.

        @param callback reference to the function to be called with the list of
            outdated packages
        @type function
        @param proc reference to the process
        @type QProcess
        @param exitCode exit code of the process
        @type int
        @param exitStatus exit status of the process
        @type QProcess.ExitStatus
        """
        packages = (
            self.__extractOutdatedPackages(proc)
            if exitStatus == QProcess.ExitStatus.NormalExit and exitCode == 0
            else []
        )
        callback(packages)
        self.__outdatedProc = None

    def checkPackagesOutdated(self, packageStarts, envName, interpreter=None):
        """
        Public method to check, if groups of packages are outdated.

        @param packageStarts list of start strings for package names to be checked
            (case insensitive)
        @type str
        @param envName name of the environment to get the packages for
        @type str
        @param interpreter path of an interpreter executable. If this is not
            None, it will override the given environment name (defaults to None)
        @type str (optional)
        @return list of tuples containing the package name, installed version
            and available version of outdated packages
        @rtype tuple of (str, str, str)
        """
        if (bool(envName) or bool(interpreter)) and any(bool(p) for p in packageStarts):
            packages = self.getOutdatedPackages(envName, interpreter=interpreter)
            filterStrings = tuple(
                start.lower() for start in packageStarts if bool(start)
            )
            filteredPackages = [
                p for p in packages if p[0].lower().startswith(filterStrings)
            ]
        else:
            filteredPackages = []

        return filteredPackages

    def getPackageDetails(self, name, version):
        """
        Public method to get package details using the PyPI JSON interface.

        @param name package name
        @type str
        @param version package version
        @type str
        @return dictionary containing PyPI package data
        @rtype dict
        """
        result = {}

        if name and version:
            url = "{0}/{1}/{2}/json".format(self.getIndexUrlPypi(), name, version)
            request = QNetworkRequest(QUrl(url))
            reply = self.__networkManager.get(request)
            while not reply.isFinished():
                QCoreApplication.processEvents()
                QThread.msleep(100)

            reply.deleteLater()
            if reply.error() == QNetworkReply.NetworkError.NoError:
                data = str(
                    reply.readAll(), Preferences.getSystem("IOEncoding"), "replace"
                )
                with contextlib.suppress(json.JSONDecodeError):
                    result = json.loads(data)

        return result

    def getPackageVersions(self, name):
        """
        Public method to get a list of versions available for the given
        package.

        @param name package name
        @type str
        @return list of available versions
        @rtype list of str
        """
        result = []

        if name:
            url = "{0}/{1}/json".format(self.getIndexUrlPypi(), name)
            request = QNetworkRequest(QUrl(url))
            reply = self.__networkManager.get(request)
            while not reply.isFinished():
                QCoreApplication.processEvents()
                QThread.msleep(100)

            reply.deleteLater()
            if reply.error() == QNetworkReply.NetworkError.NoError:
                dataStr = str(
                    reply.readAll(), Preferences.getSystem("IOEncoding"), "replace"
                )
                with contextlib.suppress(json.JSONDecodeError, KeyError):
                    data = json.loads(dataStr)
                    result = list(data["releases"].keys())

        return result

    def getFrozenPackages(
        self, envName, localPackages=True, usersite=False, requirement=None
    ):
        """
        Public method to get the list of package specifiers to freeze them.

        @param envName name of the environment to get the package specifiers
            for
        @type str
        @param localPackages flag indicating to get package specifiers for
            local packages only
        @type bool
        @param usersite flag indicating to get package specifiers for packages
            installed in user-site only
        @type bool
        @param requirement name of a requirements file
        @type str
        @return list of package specifiers
        @rtype list of str
        """
        specifiers = []

        if envName:
            interpreter = self.getVirtualenvInterpreter(envName)
            if interpreter:
                args = [
                    "-m",
                    "pip",
                    "freeze",
                ]
                if localPackages:
                    args.append("--local")
                if usersite:
                    args.append("--user")
                if requirement and os.path.exists(requirement):
                    args.append("--requirement")
                    args.append(requirement)

                success, output = self.runProcess(args, interpreter)
                if success and output:
                    specifiers = [
                        spec.strip() for spec in output.splitlines() if spec.strip()
                    ]

        return specifiers

    #######################################################################
    ## Cache handling methods below
    #######################################################################

    def showCacheInfo(self, venvName):
        """
        Public method to show some information about the pip cache.

        @param venvName name of the virtual environment to be used
        @type str
        """
        if venvName:
            interpreter = self.getVirtualenvInterpreter(venvName)
            if interpreter:
                args = ["-m", "pip", "cache", "info"]
                dia = PipDialog(self.tr("Cache Info"))
                res = dia.startProcess(interpreter, args, showArgs=False)
                if res:
                    dia.exec()

    def cacheList(self, venvName):
        """
        Public method to list files contained in the pip cache.

        @param venvName name of the virtual environment to be used
        @type str
        """
        if venvName:
            interpreter = self.getVirtualenvInterpreter(venvName)
            if interpreter:
                pattern, ok = QInputDialog.getText(
                    None,
                    self.tr("List Cached Files"),
                    self.tr("Enter a file pattern (empty for all):"),
                    QLineEdit.EchoMode.Normal,
                )

                if ok:
                    args = ["-m", "pip", "cache", "list"]
                    if pattern.strip():
                        args.append(pattern.strip())
                    dia = PipDialog(self.tr("List Cached Files"))
                    res = dia.startProcess(interpreter, args, showArgs=False)
                    if res:
                        dia.exec()

    def cacheRemove(self, venvName):
        """
        Public method to remove files from the pip cache.

        @param venvName name of the virtual environment to be used
        @type str
        """
        if venvName:
            interpreter = self.getVirtualenvInterpreter(venvName)
            if interpreter:
                pattern, ok = QInputDialog.getText(
                    None,
                    self.tr("Remove Cached Files"),
                    self.tr("Enter a file pattern:"),
                    QLineEdit.EchoMode.Normal,
                )

                if ok and pattern.strip():
                    args = ["-m", "pip", "cache", "remove", pattern.strip()]
                    dia = PipDialog(self.tr("Remove Cached Files"))
                    res = dia.startProcess(interpreter, args, showArgs=False)
                    if res:
                        dia.exec()

    def cachePurge(self, venvName):
        """
        Public method to remove all files from the pip cache.

        @param venvName name of the virtual environment to be used
        @type str
        """
        if venvName:
            interpreter = self.getVirtualenvInterpreter(venvName)
            if interpreter:
                ok = EricMessageBox.yesNo(
                    None,
                    self.tr("Purge Cache"),
                    self.tr(
                        "Do you really want to purge the pip cache? All"
                        " files need to be downloaded again."
                    ),
                )
                if ok:
                    args = ["-m", "pip", "cache", "purge"]
                    dia = PipDialog(self.tr("Purge Cache"))
                    res = dia.startProcess(interpreter, args, showArgs=False)
                    if res:
                        dia.exec()

    #######################################################################
    ## Dependency tree handling methods below
    #######################################################################

    def getDependencyTree(
        self, envName, localPackages=True, usersite=False, reverse=False
    ):
        """
        Public method to get the dependency tree of installed packages.

        @param envName name of the environment to get the packages for
        @type str
        @param localPackages flag indicating to get the tree for local
            packages only
        @type bool
        @param usersite flag indicating to get the tree for packages
            installed in user-site directory only
        @type bool
        @param reverse flag indicating to get the dependency tree in
            reverse order (i.e. list packages needed by other)
        @type bool
        @return list of nested dictionaries resembling the requested
            dependency tree
        @rtype list of dict
        """
        dependencies = []

        if envName:
            interpreter = self.getVirtualenvInterpreter(envName)
            if interpreter:
                args = ["-m", "pipdeptree", "--python", interpreter, "--json-tree"]
                if localPackages:
                    args.append("--local-only")
                if usersite:
                    args.append("--user-only")
                if reverse:
                    args.append("--reverse")

                proc = QProcess()
                proc.start(PythonUtilities.getPythonExecutable(), args)
                if proc.waitForStarted(15000) and proc.waitForFinished(30000):
                    output = str(
                        proc.readAllStandardOutput(),
                        Preferences.getSystem("IOEncoding"),
                        "replace",
                    ).strip()
                    with contextlib.suppress(json.JSONDecodeError):
                        dependencies = json.loads(output)

        return dependencies

    #######################################################################
    ## License handling methods below
    #######################################################################

    def getLicenses(self, envName):
        """
        Public method to get the licenses per package for a given environment.

        @param envName name of the environment to get the licenses for
        @type str
        @return list of dictionaries containing the license and version per
            package
        @rtype dict
        """
        licenses = []

        if envName:
            interpreter = self.getVirtualenvInterpreter(envName)
            if interpreter:
                args = [
                    os.path.join(os.path.dirname(__file__), "piplicenses.py"),
                    "--from",
                    "mixed",
                    "--with-system",
                    "--with-authors",
                    "--with-urls",
                    "--with-description",
                ]

                proc = QProcess()
                proc.start(interpreter, args)
                if proc.waitForStarted(15000) and proc.waitForFinished(30000):
                    output = str(
                        proc.readAllStandardOutput(),
                        Preferences.getSystem("IOEncoding"),
                        "replace",
                    ).strip()
                    with contextlib.suppress(json.JSONDecodeError):
                        licenses = json.loads(output)

        return licenses