Add --pre and testenv pip_pre options, no --pre by default.

6 files changed, 71 insertions, 3 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 3e73166..711f93e 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,12 @@
+1.9.0.dev
+-----------
+
+- fix issue193: Remove ``--pre`` from the default ``install_command``; by
+  default tox will now only install final releases from PyPI for unpinned
+  dependencies. Use ``pip_pre = true`` in a testenv or the ``--pre``
+  command-line option to restore the previous behavior.
+
+
 1.8.1.dev
 -----------
 
diff --git a/doc/config.txt b/doc/config.txt
index 8ce64db..2fba5f7 100644
--- a/doc/config.txt
+++ b/doc/config.txt
@@ -106,7 +106,22 @@ Complete list of settings that you can put into ``testenv*`` sections:
 
     **default**::
 
-        pip install --pre {opts} {packages}
+        pip install {opts} {packages}
+
+.. confval:: pip_pre=True|False(default)
+
+    .. versionadded:: 1.9
+
+    If ``True``, adds ``--pre`` to the ``opts`` passed to
+    :confval:`install_command`. If :confval:`install_command` uses pip, this
+    will cause it to install the latest available pre-release of any
+    dependencies without a specified version. If ``False`` (the default), pip
+    will only install final releases of unpinned dependencies.
+
+    Passing the ``--pre`` command-line option to tox will force this to
+    ``True`` for all testenvs.
+
+    Don't set this option if your :confval:`install_command` does not use pip.
 
 .. confval:: whitelist_externals=MULTI-LINE-LIST
 
diff --git a/tests/test_config.py b/tests/test_config.py
index bf74133..79e9a74 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -106,6 +106,7 @@ class TestConfigPackage:
         envconfig = config.envconfigs['python']
         assert envconfig.args_are_paths
         assert not envconfig.recreate
+        assert not envconfig.pip_pre
 
     def test_defaults_distshare(self, tmpdir, newconfig):
         config = newconfig([], "")
@@ -620,6 +621,24 @@ class TestConfigTestEnv:
             'some_install', '--arg=%s/foo' % config.toxinidir, 'python',
             '{opts}', '{packages}']
 
+    def test_pip_pre(self, newconfig):
+        config = newconfig("""
+            [testenv]
+            pip_pre=true
+        """)
+        envconfig = config.envconfigs['python']
+        assert envconfig.pip_pre
+
+    def test_pip_pre_cmdline_override(self, newconfig):
+        config = newconfig(
+            ['--pre'],
+            """
+            [testenv]
+            pip_pre=false
+        """)
+        envconfig = config.envconfigs['python']
+        assert envconfig.pip_pre
+
     def test_downloadcache(self, newconfig, monkeypatch):
         monkeypatch.delenv("PIP_DOWNLOAD_CACHE", raising=False)
         config = newconfig("""
diff --git a/tests/test_venv.py b/tests/test_venv.py
index b1d1f2e..942888f 100644
--- a/tests/test_venv.py
+++ b/tests/test_venv.py
@@ -211,6 +211,25 @@ def test_install_deps_indexserver(newmocksession):
     assert "-i ABC" in args
     assert "dep3" in args
 
+def test_install_deps_pre(newmocksession):
+    mocksession = newmocksession([], """
+        [testenv]
+        pip_pre=true
+        deps=
+            dep1
+    """)
+    venv = mocksession.getenv('python')
+    venv.create()
+    l = mocksession._pcalls
+    assert len(l) == 1
+    l[:] = []
+
+    venv.install_deps()
+    assert len(l) == 1
+    args = " ".join(l[0].args)
+    assert "--pre " in args
+    assert "dep1" in args
+
 def test_installpkg_indexserver(newmocksession, tmpdir):
     mocksession = newmocksession([], """
         [tox]
diff --git a/tox/_config.py b/tox/_config.py
index 3c1b8c2..a778b11 100644
--- a/tox/_config.py
+++ b/tox/_config.py
@@ -105,6 +105,8 @@ def prepare_parse(pkgname):
         dest="indexurl", metavar="URL",
         help="set indexserver url (if URL is of form name=url set the "
         "url for the 'name' indexserver, specifically)")
+    parser.add_argument("--pre", action="store_true", dest="pre",
+        help="pass --pre option to install_command")
     parser.add_argument("-r", "--recreate", action="store_true",
         dest="recreate",
         help="force recreation of virtual environments")
@@ -381,15 +383,17 @@ class parseini:
             downloadcache = os.environ.get("PIP_DOWNLOAD_CACHE", downloadcache)
             vc.downloadcache = py.path.local(downloadcache)
 
-        pip_default_opts = ["--pre", "{opts}", "{packages}"]
         vc.install_command = reader.getargv(
             section,
             "install_command",
-            "pip install " + " ".join(pip_default_opts),
+            "pip install {opts} {packages}",
             )
         if '{packages}' not in vc.install_command:
             raise tox.exception.ConfigError(
              "'install_command' must contain '{packages}' substitution")
+        vc.pip_pre = config.option.pre or reader.getbool(
+            section, "pip_pre", False)
+
         return vc
 
     def _getenvdata(self, reader, toxsection):
diff --git a/tox/_venv.py b/tox/_venv.py
index 0c56cc0..937a881 100644
--- a/tox/_venv.py
+++ b/tox/_venv.py
@@ -260,6 +260,8 @@ class VirtualEnv(object):
         if self.envconfig.downloadcache:
             self.envconfig.downloadcache.ensure(dir=1)
             l.append("--download-cache=%s" % self.envconfig.downloadcache)
+        if self.envconfig.pip_pre:
+            l.append("--pre")
         return l
 
     def run_install_command(self, packages, options=(),