possibility to require itself, previous version visible=False (#16132)

* possibility to require itself, previous version visible=False

* add comment

conans/client/graph/graph.py

@@ -134,6 +134,9 @@ def check_downstream_exists(self, require):
             if require.build and (self.context == CONTEXT_HOST or  # switch context
                                   require.ref.version != self.ref.version):  # or different version
                 pass
+            elif require.visible is False and require.ref.version != self.ref.version:
+                # Experimental, to support repackaging of openssl previous versions FIPS plugins
+                pass  # An invisible require doesn't conflict with itself
             else:
                 return None, self, self  # First is the require, as it is a loop => None
 

conans/test/integration/graph/test_repackaging.py

@@ -37,3 +37,115 @@ def package(self):
     client.run("install .")
     assert re.search(r"Skipped binaries(\s*)liba/1.0, libb/1.0", client.out)
     assert "repackager/1.0: Already installed!" in client.out
+
+
+def test_repackage_library_self():
+    c = TestClient()
+    c.save({"conanfile.py": GenConanfile("liba", "1.0").with_package_file("a.txt", "A1.0!")})
+    c.run("create .")
+
+    conanfile = textwrap.dedent("""
+        import os
+        from conan import ConanFile
+        from conan.tools.files import copy
+        class Pkg(ConanFile):
+            name = "liba"
+            version = "2.0"
+
+            def requirements(self):
+                self.requires("liba/1.0", visible=False)
+
+            def package(self):
+                for _, dep in self.dependencies.items():
+                    copy(self, "*", src=dep.package_folder, dst=self.package_folder)
+        """)
+    c.save({"conanfile.py": conanfile})
+    c.run("create .")
+
+    c.run("install --requires=liba/2.0 --deployer=full_deploy")
+    assert re.search(r"Skipped binaries(\s*)liba/1.0", c.out)
+    assert "liba/2.0: Already installed!" in c.out
+    assert c.load("full_deploy/host/liba/2.0/a.txt") == "A1.0!"
+
+
+def test_repackage_library_self_infinite_loop():
+    c = TestClient()
+
+    conanfile = textwrap.dedent("""
+        from conan import ConanFile
+        class Pkg(ConanFile):
+            name = "liba"
+            version = "1.0"
+
+            def requirements(self):
+                self.requires("liba/1.0", visible=False, headers=False, libs=False, run=False)
+        """)
+    c.save({"conanfile.py": conanfile})
+    c.run("create .", assert_error=True)
+    assert "There is a cycle/loop in the graph" in c.out
+
+
+def test_repackage_library_self_multiple():
+    c = TestClient()
+    c.save({"1/conanfile.py": GenConanfile("liba", "1.0").with_package_file("a1.txt", "A1.0!"),
+            "2/conanfile.py": GenConanfile("liba", "2.0").with_package_file("a2.txt", "A2.0!")})
+    c.run("create 1")
+    c.run("create 2")
+
+    conanfile = textwrap.dedent("""
+        import os
+        from conan import ConanFile
+        from conan.tools.files import copy
+        class Pkg(ConanFile):
+            name = "liba"
+            version = "3.0"
+
+            def requirements(self):
+                # To avoid conflict among liba versions
+                self.requires("liba/1.0", headers=False, libs=False, visible=False)
+                self.requires("liba/2.0", visible=False)
+
+            def package(self):
+                for _, dep in self.dependencies.items():
+                    copy(self, "*", src=dep.package_folder, dst=self.package_folder)
+        """)
+    c.save({"conanfile.py": conanfile})
+    c.run("create .")
+
+    c.run("install --requires=liba/3.0 --deployer=full_deploy")
+    assert re.search(r"Skipped binaries(\s*)liba/1.0, liba/2.0", c.out)
+    assert "liba/3.0: Already installed!" in c.out
+    assert c.load("full_deploy/host/liba/3.0/a1.txt") == "A1.0!"
+    assert c.load("full_deploy/host/liba/3.0/a2.txt") == "A2.0!"
+
+
+def test_repackage_library_self_transitive():
+    c = TestClient()
+    c.save({"a/conanfile.py": GenConanfile("liba", "1.0").with_package_file("a1.txt", "A1.0!"),
+            "b/conanfile.py": GenConanfile("libb", "1.0").with_requires("liba/1.0")})
+    c.run("create a")
+    c.run("create b")
+
+    conanfile = textwrap.dedent("""
+        import os
+        from conan import ConanFile
+        from conan.tools.files import copy
+        class Pkg(ConanFile):
+            name = "liba"
+            version = "3.0"
+
+            def requirements(self):
+                # libs=True, otherwise transitive liba is skipped
+                self.requires("libb/1.0", headers=False, libs=True, visible=False, run=False)
+
+            def package(self):
+                for _, dep in self.dependencies.items():
+                    copy(self, "*", src=dep.package_folder, dst=self.package_folder)
+        """)
+    c.save({"conanfile.py": conanfile})
+    c.run("create .")
+
+    c.run("install --requires=liba/3.0 --deployer=full_deploy")
+    assert re.search(r"Skipped binaries(\s*)liba/1.0, libb/1.0", c.out)
+    assert "liba/3.0: Already installed!" in c.out
+    assert c.load("full_deploy/host/liba/3.0/a1.txt") == "A1.0!"