[internal] Better error message for ./pants repl when using multipl…

…e resolves (pantsbuild#14327)

First part of pantsbuild#14295. Finishes Python - JVM still needs it.

[ci skip-rust]
[ci skip-build-wheels]

src/python/pants/backend/python/goals/repl.py

@@ -1,14 +1,21 @@
 # Copyright 2020 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+from __future__ import annotations
+
 import os
+from typing import Iterable
 
 from pants.backend.python.subsystems.ipython import IPython
+from pants.backend.python.subsystems.setup import PythonSetup
+from pants.backend.python.target_types import PythonResolveField
 from pants.backend.python.util_rules.interpreter_constraints import InterpreterConstraints
 from pants.backend.python.util_rules.local_dists import LocalDistsPex, LocalDistsPexRequest
 from pants.backend.python.util_rules.pex import Pex, PexRequest
 from pants.backend.python.util_rules.pex_environment import PexEnvironment
 from pants.backend.python.util_rules.pex_from_targets import (
     InterpreterConstraintsRequest,
+    NoCompatibleResolveException,
     RequirementsPexRequest,
 )
 from pants.backend.python.util_rules.python_sources import (
@@ -18,17 +25,48 @@
 from pants.core.goals.repl import ReplImplementation, ReplRequest
 from pants.engine.fs import Digest, MergeDigests
 from pants.engine.rules import Get, MultiGet, collect_rules, rule
-from pants.engine.target import TransitiveTargets, TransitiveTargetsRequest
+from pants.engine.target import Target, TransitiveTargets, TransitiveTargetsRequest
 from pants.engine.unions import UnionRule
 from pants.util.logging import LogLevel
 
 
+def validate_compatible_resolve(root_targets: Iterable[Target], python_setup: PythonSetup) -> None:
+    """Eagerly validate that all roots are compatible.
+
+    We already end up checking this in pex_from_targets.py, but this is a more eager check so that
+    we have a better error message.
+    """
+    root_resolves = {
+        root[PythonResolveField].normalized_value(python_setup)
+        for root in root_targets
+        if root.has_field(PythonResolveField)
+    }
+    if len(root_resolves) > 1:
+        raise NoCompatibleResolveException(
+            python_setup,
+            "The input targets did not have a resolve in common",
+            root_targets,
+            (
+                "To work around this, choose which resolve you want to use from above. "
+                'Then, run `./pants peek :: | jq -r \'.[] | select(.resolve == "example") | '
+                '.["address"]\' | xargs ./pants repl`, where you replace "example" with the '
+                "resolve name, and possibly replace the specs `::` with what you were using "
+                "before. This will result in opening a REPL with only targets using the desired "
+                "resolve."
+            ),
+        )
+
+
 class PythonRepl(ReplImplementation):
     name = "python"
 
 
 @rule(level=LogLevel.DEBUG)
-async def create_python_repl_request(request: PythonRepl, pex_env: PexEnvironment) -> ReplRequest:
+async def create_python_repl_request(
+    request: PythonRepl, pex_env: PexEnvironment, python_setup: PythonSetup
+) -> ReplRequest:
+    validate_compatible_resolve(request.targets, python_setup)
+
     interpreter_constraints, transitive_targets = await MultiGet(
         Get(InterpreterConstraints, InterpreterConstraintsRequest(request.addresses)),
         Get(TransitiveTargets, TransitiveTargetsRequest(request.addresses)),
@@ -79,8 +117,10 @@ class IPythonRepl(ReplImplementation):
 
 @rule(level=LogLevel.DEBUG)
 async def create_ipython_repl_request(
-    request: IPythonRepl, ipython: IPython, pex_env: PexEnvironment
+    request: IPythonRepl, ipython: IPython, pex_env: PexEnvironment, python_setup: PythonSetup
 ) -> ReplRequest:
+    validate_compatible_resolve(request.targets, python_setup)
+
     interpreter_constraints, transitive_targets = await MultiGet(
         Get(InterpreterConstraints, InterpreterConstraintsRequest(request.addresses)),
         Get(TransitiveTargets, TransitiveTargetsRequest(request.addresses)),

src/python/pants/backend/python/goals/repl_integration_test.py

@@ -3,20 +3,29 @@
 
 from __future__ import annotations
 
+from textwrap import dedent
+
 import pytest
 
 from pants.backend.codegen.protobuf.target_types import ProtobufSourceTarget
 from pants.backend.python.goals import repl as python_repl
 from pants.backend.python.subsystems.ipython import rules as ipython_subsystem_rules
 from pants.backend.python.subsystems.setup import PythonSetup
-from pants.backend.python.target_types import PythonSourcesGeneratorTarget
+from pants.backend.python.target_types import PythonSourcesGeneratorTarget, PythonSourceTarget
 from pants.backend.python.util_rules import local_dists, pex_from_targets
 from pants.backend.python.util_rules.pex import PexProcess
+from pants.backend.python.util_rules.pex_from_targets import NoCompatibleResolveException
 from pants.core.goals.repl import Repl
 from pants.core.goals.repl import rules as repl_rules
 from pants.engine.process import Process
 from pants.testutil.python_interpreter_selection import all_major_minor_python_versions
-from pants.testutil.rule_runner import GoalRuleResult, QueryRule, RuleRunner, mock_console
+from pants.testutil.rule_runner import (
+    GoalRuleResult,
+    QueryRule,
+    RuleRunner,
+    engine_error,
+    mock_console,
+)
 
 
 @pytest.fixture
@@ -30,7 +39,7 @@ def rule_runner() -> RuleRunner:
             *local_dists.rules(),
             QueryRule(Process, (PexProcess,)),
         ],
-        target_types=[PythonSourcesGeneratorTarget, ProtobufSourceTarget],
+        target_types=[PythonSourcesGeneratorTarget, ProtobufSourceTarget, PythonSourceTarget],
     )
     rule_runner.write_files(
         {
@@ -45,21 +54,23 @@ def rule_runner() -> RuleRunner:
     return rule_runner
 
 
-def run_repl(rule_runner: RuleRunner, *, extra_args: list[str] | None = None) -> GoalRuleResult:
+def run_repl(
+    rule_runner: RuleRunner, args: list[str], *, global_args: list[str] | None = None
+) -> GoalRuleResult:
     # TODO(#9108): Expand `mock_console` to allow for providing input for the repl to verify
     # that, e.g., the generated protobuf code is available. Right now this test prepares for
     # that by including generated code, but cannot actually verify it.
     with mock_console(rule_runner.options_bootstrapper):
         return rule_runner.run_goal_rule(
             Repl,
-            global_args=extra_args or (),
-            args=["src/python/lib.py"],
+            global_args=global_args or (),
+            args=args,
             env_inherit={"PATH", "PYENV_ROOT", "HOME"},
         )
 
 
 def test_default_repl(rule_runner: RuleRunner) -> None:
-    assert run_repl(rule_runner).exit_code == 0
+    assert run_repl(rule_runner, ["src/python/lib.py"]).exit_code == 0
 
 
 @pytest.mark.platform_specific_behavior
@@ -71,10 +82,28 @@ def test_ipython(rule_runner: RuleRunner, major_minor_interpreter: str) -> None:
     assert (
         run_repl(
             rule_runner,
-            extra_args=[
+            ["src/python/lib.py"],
+            global_args=[
                 "--repl-shell=ipython",
                 f"--python-interpreter-constraints=['=={major_minor_interpreter}.*']",
             ],
         ).exit_code
         == 0
     )
+
+
+def test_eagerly_validate_roots_have_common_resolve(rule_runner: RuleRunner) -> None:
+    rule_runner.write_files(
+        {
+            "BUILD": dedent(
+                """\
+                python_source(name='t1', source='f.py', resolve='a')
+                python_source(name='t2', source='f.py', resolve='b')
+                """
+            )
+        }
+    )
+    with engine_error(NoCompatibleResolveException, contains="./pants peek"):
+        run_repl(
+            rule_runner, ["//:t1", "//:t2"], global_args=["--python-resolves={'a': '', 'b': ''}"]
+        )

src/python/pants/backend/python/util_rules/pex_from_targets.py

@@ -200,7 +200,11 @@ class NoCompatibleResolveException(Exception):
     """No compatible resolve could be found for a set of targets."""
 
     def __init__(
-        self, python_setup: PythonSetup, msg_prefix: str, relevant_targets: Iterable[Target]
+        self,
+        python_setup: PythonSetup,
+        msg_prefix: str,
+        relevant_targets: Iterable[Target],
+        msg_suffix: str = "",
     ) -> None:
         resolves_to_addresses = defaultdict(list)
         for tgt in relevant_targets:
@@ -224,22 +228,14 @@ def __init__(
             "Targets which will be used together must all have the same resolve (from the "
             f"[resolve]({doc_url('reference-python_test#coderesolvecode')}) or "
             f"[compatible_resolves]({doc_url('reference-python_requirement#codecompatible_resolvescode')}) "
-            "fields) in common."
+            "fields) in common." + (f"\n\n{msg_suffix}" if msg_suffix else "")
         )
 
 
 @rule
 async def choose_python_resolve(
     request: ChosenPythonResolveRequest, python_setup: PythonSetup
 ) -> ChosenPythonResolve:
-    # If there are no targets, we fall back to the default resolve. This is relevant,
-    # for example, when running `./pants repl` with no specs.
-    if not request.addresses:
-        return ChosenPythonResolve(
-            name=python_setup.default_resolve,
-            lockfile_path=python_setup.resolves[python_setup.default_resolve],
-        )
-
     transitive_targets = await Get(TransitiveTargets, TransitiveTargetsRequest(request.addresses))
 
     # First, choose the resolve by inspecting the root targets.
@@ -249,17 +245,14 @@ async def choose_python_resolve(
         if root.has_field(PythonResolveField)
     }
     if not root_resolves:
-        root_targets = bullet_list(
-            f"{tgt.address.spec} ({tgt.alias})" for tgt in transitive_targets.roots
-        )
-        raise AssertionError(
-            "Used `ChosenPythonResolveRequest` with input addresses that don't have the "
-            f"`PythonResolveField` field registered:\n\n{root_targets}\n\n"
-            "If you encountered this bug while using core Pants functionality, please open a "
-            "bug at https://github.com/pantsbuild/pants/issues/new with this error message when "
-            "`--print-stacktrace` is enabled. If this is from your own plugin, register "
-            "`PythonResolveField` on the relevant target types."
+        # If there are no targets, we fall back to the default resolve. This is relevant,
+        # for example, when running `./pants repl` with no specs or directly on
+        # python_requirement targets.
+        return ChosenPythonResolve(
+            name=python_setup.default_resolve,
+            lockfile_path=python_setup.resolves[python_setup.default_resolve],
         )
+
     if len(root_resolves) > 1:
         raise NoCompatibleResolveException(
             python_setup,