Ensure pip.list_all_versions works across multiple pip versions

Refs #60085

salt/modules/pip.py

@@ -1597,7 +1597,6 @@ def list_all_versions(
     """
     cwd = _pip_bin_env(cwd, bin_env)
     cmd = _get_pip_bin(bin_env)
-    cmd.extend(["install", "{}==versions".format(pkg)])
 
     if index_url:
         if not salt.utils.url.validate(index_url, VALID_PROTOS):
@@ -1611,6 +1610,17 @@ def list_all_versions(
             )
         cmd.extend(["--extra-index-url", extra_index_url])
 
+    # Is the `pip index` command available
+    pip_version = version(bin_env=bin_env, cwd=cwd, user=user)
+    if salt.utils.versions.compare(ver1=pip_version, oper=">=", ver2="21.2"):
+        regex = re.compile(r"\s*Available versions: (.*)")
+        cmd.extend(["index", "versions", pkg])
+    else:
+        if salt.utils.versions.compare(ver1=pip_version, oper=">=", ver2="20.3"):
+            cmd.append("--use-deprecated=legacy-resolver")
+        regex = re.compile(r"\s*Could not find a version.* \(from versions: (.*)\)")
+        cmd.extend(["install", "{}==versions".format(pkg)])
+
     cmd_kwargs = dict(
         cwd=cwd, runas=user, output_loglevel="quiet", redirect_stderr=True
     )
@@ -1633,9 +1643,7 @@ def list_all_versions(
 
     versions = []
     for line in result["stdout"].splitlines():
-        match = re.search(
-            r"\s*Could not find a version.* \(from versions: (.*)\)", line
-        )
+        match = regex.search(line)
         if match:
             versions = [
                 v for v in match.group(1).split(", ") if v and excludes.match(v)

tests/pytests/functional/modules/test_pip.py

@@ -0,0 +1,25 @@
+import sys
+
+import pytest
+from tests.support.helpers import VirtualEnv
+
+
+@pytest.mark.parametrize(
+    "pip_version",
+    (
+        "pip==9.0.3",
+        "pip<20.0",
+        "pip<21.0",
+        "pip>=21.0",
+    ),
+)
+def test_list_available_packages(modules, pip_version, tmp_path):
+    if sys.version_info < (3, 6) and pip_version == "pip>=21.0":
+        pytest.skip("{} is not avaiable on Py3.5".format(pip_version))
+    with VirtualEnv(venv_dir=tmp_path, pip_requirement=pip_version) as virtualenv:
+        virtualenv.install("-U", pip_version)
+        package_name = "pep8"
+        available_versions = modules.pip.list_all_versions(
+            package_name, bin_env=str(virtualenv.venv_bin_dir)
+        )
+        assert available_versions