inspection: ad each extra package as a dependency

Resolves: #3129

poetry/inspection/info.py

@@ -165,6 +165,8 @@ def to_package(
                 package.requires = poetry_package.requires
                 return package
 
+        seen_requirements = set()
+
         for req in self.requires_dist or []:
             try:
                 # Attempt to parse the PEP-508 requirement string
@@ -191,8 +193,11 @@ def to_package(
 
                     package.extras[extra].append(dependency)
 
-            if dependency not in package.requires:
+            req = dependency.to_pep_508(with_extras=True)
+
+            if req not in seen_requirements:
                 package.requires.append(dependency)
+                seen_requirements.add(req)
 
         return package
 

tests/repositories/test_legacy_repository.py

@@ -117,7 +117,7 @@ def test_get_package_information_skips_dependencies_with_invalid_constraints():
         package.description == "Python Language Server for the Language Server Protocol"
     )
 
-    assert 19 == len(package.requires)
+    assert 25 == len(package.requires)
     assert sorted(
         [r for r in package.requires if not r.is_optional()], key=lambda r: r.name
     ) == [
@@ -216,7 +216,7 @@ def test_get_package_from_both_py2_and_py3_specific_wheels():
     assert "ipython" == package.name
     assert "5.7.0" == package.version.text
     assert "*" == package.python_versions
-    assert 26 == len(package.requires)
+    assert 41 == len(package.requires)
 
     expected = [
         Dependency("appnope", "*"),

tests/repositories/test_pypi_repository.py

@@ -165,7 +165,7 @@ def test_pypi_repository_supports_reading_bz2_files():
     package = repo.package("twisted", "18.9.0")
 
     assert package.name == "twisted"
-    assert 28 == len(package.requires)
+    assert 71 == len(package.requires)
     assert sorted(
         [r for r in package.requires if not r.is_optional()], key=lambda r: r.name
     ) == [