Proposed implementation for #515: Install development dependencies in…

…crementally

conda_lock/conda_lock.py

@@ -197,12 +197,13 @@ def do_validate_platform(lockfile: str) -> None:
         )
 
 
-def do_conda_install(
+def do_conda_create_or_update(
     conda: PathLike,
     prefix: "str | None",
     name: "str | None",
     file: pathlib.Path,
     copy: bool,
+    update: bool,
 ) -> None:
     _conda = partial(_invoke_conda, conda, prefix, name, check_call=True)
 
@@ -218,24 +219,38 @@ def do_conda_install(
     else:
         pip_requirements = []
 
-    env_prefix = ["env"] if kind == "env" and not is_micromamba(conda) else []
+    env_prefix = (
+        ["env"] if (kind == "env" or update) and not is_micromamba(conda) else []
+    )
     copy_arg = ["--copy"] if kind != "env" and copy else []
     yes_arg = ["--yes"] if kind != "env" else []
+    prune_arg = ["--prune"] if update else []
 
     _conda(
         [
             *env_prefix,
-            "create",
+            "update" if update else "create",
             *copy_arg,
             "--file",
             str(file),
             *yes_arg,
+            *prune_arg,
         ],
     )
 
     if not pip_requirements:
         return
 
+    if update:
+        logger.warning(
+            (
+                "If you have have removed any pip dependencies from your lockfile, "
+                "they will not be removed from your environment. To remove them, "
+                "run `conda-lock install` to create a completely fresh conda environment. \n\n"
+                "You can safely ignore this message if your lockfile is unchanged since you created it."
+            )
+        )
+
     with temporary_file_with_contents("\n".join(pip_requirements)) as requirements_path:
         _conda(["run"], ["pip", "install", "--no-deps", "-r", str(requirements_path)])
 
@@ -1396,6 +1411,7 @@ def lock(
     default=False,
     help="don't attempt to use or install micromamba.",
 )
+@click.option("--update", default=False, help="Update environment if available.")
 @click.option(
     "--copy",
     is_flag=True,
@@ -1454,6 +1470,7 @@ def install(
     validate_platform: bool,
     log_level: TLogLevel,
     dev: bool,
+    update: bool,
     extras: List[str],
 ) -> None:
     # bail out if we do not encounter the lockfile
@@ -1469,7 +1486,12 @@ def install(
     )
     _conda_exe = determine_conda_executable(conda, mamba=mamba, micromamba=micromamba)
     install_func = partial(
-        do_conda_install, conda=_conda_exe, prefix=prefix, name=name, copy=copy
+        do_conda_create_or_update,
+        conda=_conda_exe,
+        prefix=prefix,
+        name=name,
+        copy=copy,
+        update=update,
     )
     if validate_platform and not lock_file.name.endswith(DEFAULT_LOCKFILE_NAME):
         lockfile_contents = read_file(lock_file)

tests/test_conda_lock.py

@@ -162,6 +162,11 @@ def zlib_environment(tmp_path: Path):
     return clone_test_dir("zlib", tmp_path).joinpath("environment.yml")
 
 
+@pytest.fixture
+def zlib_dev_environment(tmp_path: Path):
+    return clone_test_dir("zlib", tmp_path).joinpath("environment.dev.yml")
+
+
 @pytest.fixture
 def input_hash_zlib_environment(tmp_path: Path):
     return clone_test_dir("test-input-hash-zlib", tmp_path).joinpath("environment.yml")
@@ -1578,6 +1583,14 @@ def _check_package_installed(package: str, prefix: str):
     return True
 
 
+def _check_package_not_installed(package: str, prefix: str):
+    import glob
+
+    files = list(glob.glob(f"{prefix}/conda-meta/{package}-*.json"))
+    assert len(files) == 0
+    return True
+
+
 def conda_supports_env(conda_exe: str):
     try:
         subprocess.check_call(
@@ -1690,6 +1703,133 @@ def invoke_install(*extra_args: str) -> CliResult:
         ), f"Package {package} does not exist in {prefix} environment"
 
 
+@pytest.mark.parametrize("kind", ["explicit", "env"])
+@flaky
+def test_install_with_update(
+    request: "pytest.FixtureRequest",
+    kind: str,
+    tmp_path: Path,
+    conda_exe: str,
+    zlib_environment: Path,
+    zlib_dev_environment: Path,
+    monkeypatch: "pytest.MonkeyPatch",
+    capsys: "pytest.CaptureFixture[str]",
+):
+    # Test that we can lock, install without dev dependencies, then use the update flag to install the dev dependencies
+    if is_micromamba(conda_exe):
+        monkeypatch.setenv("CONDA_FLAGS", "-v")
+    if kind == "env" and not conda_supports_env(conda_exe):
+        pytest.skip(
+            f"Standalone conda @ '{conda_exe}' does not support materializing from environment files."
+        )
+
+    root_prefix = tmp_path / "root_prefix"
+    generated_lockfile_path = tmp_path / "generated_lockfiles"
+
+    root_prefix.mkdir(exist_ok=True)
+    generated_lockfile_path.mkdir(exist_ok=True)
+    monkeypatch.chdir(generated_lockfile_path)
+
+    package = "zlib"
+    dev_dependency = "pydantic"
+    platform = "linux-64"
+
+    lock_filename_template = (
+        request.node.name + "conda-{platform}-{dev-dependencies}.lock"
+    )
+    lock_filename = (
+        request.node.name
+        + "conda-linux-64-true.lock"
+        + (".yml" if kind == "env" else "")
+    )
+
+    with capsys.disabled():
+        runner = CliRunner(mix_stderr=False)
+        result = runner.invoke(
+            main,
+            [
+                "lock",
+                "--conda",
+                conda_exe,
+                "-p",
+                platform,
+                "-f",
+                str(zlib_environment),
+                "-f",
+                str(zlib_dev_environment),
+                "-k",
+                kind,
+                "--filename-template",
+                lock_filename_template,
+            ],
+            catch_exceptions=False,
+        )
+    print(result.stdout, file=sys.stdout)
+    print(result.stderr, file=sys.stderr)
+    assert result.exit_code == 0
+
+    prefix = root_prefix / "test_env"
+
+    def invoke_install(*extra_args: str) -> CliResult:
+        with capsys.disabled():
+            return runner.invoke(
+                main,
+                [
+                    "install",
+                    "--conda",
+                    conda_exe,
+                    "--prefix",
+                    str(prefix),
+                    *extra_args,
+                    lock_filename,
+                ],
+                catch_exceptions=False,
+            )
+
+    context: ContextManager
+    if sys.platform.lower().startswith("linux"):
+        context = contextlib.nullcontext()
+    else:
+        # since by default we do platform validation we would expect this to fail
+        context = pytest.raises(PlatformValidationError)
+
+    with context, install_lock():
+        result = invoke_install()
+    print(result.stdout, file=sys.stdout)
+    print(result.stderr, file=sys.stderr)
+    if Path(lock_filename).exists():
+        logging.debug(
+            "lockfile contents: \n\n=======\n%s\n\n==========",
+            Path(lock_filename).read_text(),
+        )
+
+    assert _check_package_installed(
+        package=package,
+        prefix=str(prefix),
+    ), f"Package {package} does not exist in {prefix} environment"
+
+    assert _check_package_not_installed(
+        package=dev_dependency,
+        prefix=str(prefix),
+    ), f"Package {dev_dependency} exists in {prefix} environment"
+
+    # Now try to install with the update and dev dependencies flag
+    with install_lock():
+        result = invoke_install("--update", "--dev")
+    print(result.stdout, file=sys.stdout)
+    print(result.stderr, file=sys.stderr)
+    if Path(lock_filename).exists():
+        logging.debug(
+            "lockfile contents: \n\n=======\n%s\n\n==========",
+            Path(lock_filename).read_text(),
+        )
+
+    assert _check_package_installed(
+        package=dev_dependency,
+        prefix=str(prefix),
+    ), f"Package {package} does not exist in {prefix} environment"
+
+
 @pytest.mark.parametrize(
     "line,stripped",
     (

tests/zlib/environment.dev.yml

@@ -0,0 +1,6 @@
+channels:
+    - conda-forge
+    - defaults
+dependencies:
+    - pydantic
+category: dev