Fix issues with external requirements files and force dep

Using --force-dep while your [testenv] included a dep similar to "-r{toxinidir}/reqs.txt" would cause an unhandled exception similar to: ValueError: ('Expected version spec in', '-rrequirements-test.txt', 'at', 'requirements-test.txt')

2 files changed, 90 insertions, 2 deletions

diff --git a/tests/test_config.py b/tests/test_config.py
index 461b7b6..bcc1836 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -1384,6 +1384,59 @@ class TestCmdInvocation:
             r'*deps=*dep1, dep2==5.0*',
         ])
 
+    def test_force_dep_with_requirements_txt_file(self, cmd, initproj):
+        """
+        Make sure we can override dependencies configured in external reqs.txt
+        when using the command line option --force-dep.
+        """
+        initproj("example123-0.5", filedefs={
+            'tox.ini': '''
+            [tox]
+
+            [testenv]
+            deps=
+                dep1==1.0
+                -r{toxinidir}/reqs.txt
+            ''',
+            'reqs.txt': '''
+            -e git://hello/world/git
+            dep2>=2.0
+            -i http://index.local/
+            dep3
+            dep4==4.0
+            -r reqs2.txt
+            ''',
+            'reqs2.txt': '''
+            dep5>=2.2
+            '''
+        })
+        config = parseconfig(
+            ['--force-dep=dep1==1.5', '--force-dep=dep2==2.1',
+             '--force-dep=dep3==3.0'])
+        assert config.option.force_dep == [
+            'dep1==1.5', 'dep2==2.1', 'dep3==3.0']
+
+        deps = config.envconfigs['python'].deps
+        assert len(deps) == 2
+        assert deps[0].name == 'dep1==1.5'
+        include_file = deps[1].name
+        assert include_file.startswith('-r')
+        with open(include_file[2:]) as reqs:
+            lines = [x.strip() for x in reqs.readlines()]
+            assert len(lines) == 6
+            second_file = lines.pop(len(lines) - 1)
+            assert second_file.startswith('-r')
+            assert lines == [
+                '-e git://hello/world/git',
+                'dep2==2.1',
+                '-i http://index.local/',
+                'dep3==3.0',
+                'dep4==4.0',
+            ]
+        with open(second_file[2:]) as reqs2:
+            lines = [x.strip() for x in reqs2.readlines()]
+            assert lines == ['dep5>=2.2']
+
 class TestArgumentParser:
 
     def test_dash_e_single_1(self):
diff --git a/tox/_config.py b/tox/_config.py
index ceae6b9..de75e2b 100644
--- a/tox/_config.py
+++ b/tox/_config.py
@@ -1,4 +1,5 @@
 import argparse
+import tempfile
 import os
 import random
 import sys
@@ -363,6 +364,7 @@ class parseini:
         vc.whitelist_externals = reader.getlist(section,
                                                 "whitelist_externals")
         vc.deps = []
+        reqs_files = []
         for depline in reader.getlist(section, "deps"):
             m = re.match(r":(\w+):\s*(\S+)", depline)
             if m:
@@ -371,8 +373,41 @@ class parseini:
             else:
                 name = depline.strip()
                 ixserver = None
-            name = self._replace_forced_dep(name, config)
-            vc.deps.append(DepConfig(name, ixserver))
+
+            if name[:2] == '-r':  # not a dependency, but a file full of dependencies
+                fd, temp_path = tempfile.mkstemp()
+                reqs_files.append((name[2:].strip(), fd, temp_path))
+                vc.deps.append(DepConfig('-r%s' % temp_path))
+            elif name[0] == '-':  # an option to be sent to pip
+                vc.deps.append(DepConfig(name, ixserver))
+            else:
+                name = self._replace_forced_dep(name, config)
+                vc.deps.append(DepConfig(name, ixserver))
+
+        for reqs_file, fd, temp_path in reqs_files:
+            lines = []
+            with open(reqs_file, 'r') as reqs:
+                for req in reqs.readlines():
+                    req = req.strip()
+                    if not req:
+                        continue
+
+                    if req.startswith('-'):
+                        if req.startswith('-r'):
+                            new_fd, new_temp_path = tempfile.mkstemp()
+                            reqs_files.append((req[2:].strip(), new_fd, new_temp_path))
+                            lines.append('-r' + new_temp_path)
+                        else:
+                            lines.append(req)
+                        continue
+
+                    name = self._replace_forced_dep(req, config)
+                    lines.append(name)
+
+            with open(temp_path, mode='w') as temp_reqs:
+                temp_reqs.writelines(os.linesep.join(lines))
+                os.close(fd)
+
         vc.distribute = reader.getbool(section, "distribute", False)
         vc.sitepackages = self.config.option.sitepackages or \
                           reader.getbool(section, "sitepackages", False)