Apply version constraint specified during package upgrade with -P

README.rst

@@ -155,7 +155,7 @@ To update a specific package to the latest or a specific version use the
 
     $ pip-compile --upgrade-package flask  # only update the flask package
     $ pip-compile --upgrade-package flask --upgrade-package requests  # update both the flask and requests packages
-    $ pip-compile -P flask -P requests  # same as above, but shorter
+    $ pip-compile -P flask -P requests==2.0.0  # update the flask package to the latest, and requests to v2.0.0
 
 If you use multiple Python versions, you can run ``pip-compile`` as
 ``py -X.Y -m piptools compile ...`` on Windows and

piptools/scripts/compile.py

@@ -129,15 +129,18 @@ def cli(verbose, dry_run, pre, rebuild, find_links, index_url, extra_index_url,
     session = pip_command._build_session(pip_options)
     repository = PyPIRepository(pip_options, session)
 
+    upgrade_install_reqs = {}
     # Proxy with a LocalRequirementsRepository if --upgrade is not specified
     # (= default invocation)
     if not upgrade and os.path.exists(dst_file):
         ireqs = parse_requirements(dst_file, finder=repository.finder, session=repository.session, options=pip_options)
         # Exclude packages from --upgrade-package/-P from the existing pins: We want to upgrade.
-        upgrade_pkgs_key = {key_from_req(install_req_from_line(pkg).req) for pkg in upgrade_packages}
+        upgrade_reqs_gen = (install_req_from_line(pkg) for pkg in upgrade_packages)
+        upgrade_install_reqs = {key_from_req(install_req.req): install_req for install_req in upgrade_reqs_gen}
+
         existing_pins = {key_from_req(ireq.req): ireq
                          for ireq in ireqs
-                         if is_pinned_requirement(ireq) and key_from_req(ireq.req) not in upgrade_pkgs_key}
+                         if is_pinned_requirement(ireq) and key_from_req(ireq.req) not in upgrade_install_reqs}
         repository = LocalRequirementsRepository(existing_pins, repository)
 
     log.debug('Using indexes:')
@@ -178,6 +181,8 @@ def cli(verbose, dry_run, pre, rebuild, find_links, index_url, extra_index_url,
             constraints.extend(parse_requirements(
                 src_file, finder=repository.finder, session=repository.session, options=pip_options))
 
+    constraints.extend(upgrade_install_reqs.values())
+
     # Filter out pip environment markers which do not match (PEP496)
     constraints = [req for req in constraints
                    if req.markers is None or req.markers.evaluate()]

tests/test_cli.py

@@ -326,7 +326,29 @@ def test_upgrade_packages_option(tmpdir):
             req_in.write('small-fake-a==0.1\nsmall-fake-b==0.1')
 
         out = runner.invoke(cli, [
-            '-P', 'small_fake_b',
+            '-P', 'small-fake-b',
+            '-f', fake_package_dir,
+        ])
+
+        assert out.exit_code == 0
+        assert 'small-fake-a==0.1' in out.output
+        assert 'small-fake-b==0.3' in out.output
+
+
+def test_upgrade_packages_version_option(tmpdir):
+    """
+    piptools respects --upgrade-package/-P inline list with specified versions.
+    """
+    fake_package_dir = os.path.join(os.path.split(__file__)[0], 'test_data', 'minimal_wheels')
+    runner = CliRunner()
+    with runner.isolated_filesystem():
+        with open('requirements.in', 'w') as req_in:
+            req_in.write('small-fake-a\nsmall-fake-b')
+        with open('requirements.txt', 'w') as req_in:
+            req_in.write('small-fake-a==0.1\nsmall-fake-b==0.1')
+
+        out = runner.invoke(cli, [
+            '-P', 'small-fake-b==0.2',
             '-f', fake_package_dir,
         ])