Fix pex3 venv create --link-python for --pex-repository.

[jasonwbarnett]

pex3 venv create --link-python for a foreign platform fails when the venv is installed from a --pex-repository:

A distribution for psutil could not be resolved for <local python>.
Found 1 distribution for psutil that does not apply:
1.) The wheel tags for psutil 5.9.5 are cp36-abi3-manylinux_2_12_x86_64, ... which do not match
    the supported tags of <local python>: cp313-cp313-manylinux_2_39_aarch64 ...

The distributions themselves install fine — it is populating the venv's sources that fails. _populate_first_party re-resolves the repository PEX to build the pex-repl script's activated_dists, and that resolve runs against a local interpreter, which a PEX built for the foreign platform alone holds nothing for. _install_from_pex has already resolved the distributions for the target, so this passes those down instead; the PEX_TOOLS=1 ... venv path keeps re-resolving, where the PEX and the interpreter always agree.

This is the combination Pants uses — it always invokes pex3 venv create with --pex-repository — so #3279 is unreachable from Pants without it.

Repro and verification, on a linux aarch64 host:

pex psutil==5.9.5 --platform linux_x86_64-cp-313-cp313 -o psutil.pex
pex3 venv create -d venv --pex-repository psutil.pex --platform linux_x86_64-cp-313-cp313 \
    --python-path $(command -v python3.13) --link-python /opt/python/bin/bob

Before: the error above. After: bin/python, bin/python3 and bin/python3.13 all link to /opt/python/bin/bob, and lib/python3.13/site-packages/psutil/_psutil_linux.abi3.so is ELF 64-bit LSB shared object, x86-64.

test_foreign_target_link_python_from_pex_repository covers it. I could not run it locally — the py310 fixture's CPython 3.10.7 build fails in my environment (ensurepip exits non-zero) — so CI is its first run; the commands above are the same shape by hand. uv run dev-cmd format lint typecheck is green.

Written with Claude Code, as was #3279.

🤖 Generated with Claude Code

https://claude.ai/code/session_012imZdyz1fhVXRNKPjbhSDw

[jsirois]

@jasonwbarnett no more Claude please. I haven't had to write an AI policy yet for Pex, but this is the 2nd PR from the altana-ai/pex repo where I can not contribute:

:; git push https://github.com/altana-ai/pex HEAD:venv-create-pex-repository-link-python
remote: Permission to altana-ai/pex.git denied to jsirois.
fatal: unable to access 'https://github.com/altana-ai/pex/': The requested URL returned error: 403

Now the altana-ai/pex repo thing may or may not have anything to do with Claude, but regardless, two strikes and you're out.

I'll do another hand merge to include these:

From 45a9df95bde15cda58c4e6058aca126ad0c2992e Mon Sep 17 00:00:00 2001
From: John Sirois <john.sirois@gmail.com>
Date: Thu, 17 Sep 2026 23:29:02 -0700
Subject: [PATCH 1/2] Only resolve once.

---
 pex/cli/commands/venv.py |  6 +++---
 pex/venv/installer.py    | 17 +++++++----------
 2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/pex/cli/commands/venv.py b/pex/cli/commands/venv.py
index 98aaf998..6f746150 100644
--- a/pex/cli/commands/venv.py
+++ b/pex/cli/commands/venv.py
@@ -42,7 +42,7 @@ from pex.venv.installer_configuration import InstallerConfiguration
 from pex.venv.virtualenv import Virtualenv

 if TYPE_CHECKING:
-    from typing import Any, Dict, Iterable, Optional, Sequence, Union
+    from typing import Any, Dict, Optional, Sequence, Union


 logger = logging.getLogger(__name__)
@@ -495,7 +495,7 @@ def _install_from_pex(
     pex,  # type: PEX
     installer_configuration,  # type: InstallerConfiguration
     provenance,  # type: Provenance
-    distributions,  # type: Iterable[Distribution]
+    distributions,  # type: Sequence[Distribution]
     dest_dir,  # type: str
     hermetic_scripts,  # type: bool
     venv=None,  # type: Optional[Virtualenv]
@@ -531,9 +531,9 @@ def _install_from_pex(
                 venv=venv,
                 pex=pex,
                 provenance=provenance,
+                activated_dists=distributions,
                 bin_path=installer_configuration.bin_path,
                 hermetic_scripts=hermetic_scripts,
-                activated_dists=distributions,
             )
         else:
             installer.populate_flat_sources(dst=dest_dir, pex=pex, provenance=provenance)
diff --git a/pex/venv/installer.py b/pex/venv/installer.py
index 2241c75e..33becfc0 100644
--- a/pex/venv/installer.py
+++ b/pex/venv/installer.py
@@ -360,11 +360,11 @@ def populate_venv_sources(
     venv,  # type: Virtualenv
     pex,  # type: PEX
     provenance,  # type: Provenance
+    activated_dists,  # type: Sequence[Distribution]
     bin_path=BinPath.FALSE,  # type: BinPath.Value
     hermetic_scripts=True,  # type: bool
     shebang=None,  # type: Optional[str]
     set_last_access=True,  # type: bool
-    activated_dists=None,  # type: Optional[Iterable[Distribution]]
 ):
     # type: (...) -> str

@@ -374,11 +374,11 @@ def populate_venv_sources(
             target_dir=provenance.target_dir,
             venv=venv,
             pex=pex,
+            activated_dists=activated_dists,
             shebang=shebang,
             venv_python=provenance.target_python,
             bin_path=bin_path,
             set_last_access=set_last_access,
-            activated_dists=activated_dists,
         )
     )
     return shebang
@@ -422,10 +422,11 @@ def populate_venv_from_pex(
     shebang = provenance.calculate_shebang(hermetic_scripts=hermetic_scripts)
     top_level_source_packages = tuple(iter_top_level_source_packages(pex))

+    distributions = tuple(pex.resolve())
     if scope in (InstallScope.ALL, InstallScope.DEPS_ONLY):
         populate_venv_distributions(
             venv=venv,
-            distributions=pex.resolve(),
+            distributions=distributions,
             copy_mode=copy_mode,
             hermetic_scripts=hermetic_scripts,
             provenance=provenance,
@@ -436,6 +437,7 @@ def populate_venv_from_pex(
         populate_venv_sources(
             venv=venv,
             pex=pex,
+            activated_dists=distributions,
             bin_path=bin_path,
             hermetic_scripts=hermetic_scripts,
             provenance=provenance,
@@ -747,11 +749,11 @@ def _populate_first_party(
     target_dir,  # type: str
     venv,  # type: Virtualenv
     pex,  # type: PEX
+    activated_dists,  # type: Sequence[Distribution]
     shebang,  # type: str
     venv_python,  # type: str
     bin_path,  # type: BinPath.Value
     set_last_access,  # type: bool
-    activated_dists=None,  # type: Optional[Iterable[Distribution]]
 ):
     # type: (...) -> Iterator[Tuple[Text, Text]]

@@ -767,12 +769,7 @@ def _populate_first_party(
         target_dir=target_dir,
         venv=venv,
         pex_info=pex_info,
-        # N.B.: A venv laid out for a foreign platform cannot re-resolve the PEX: that resolve
-        # runs against a local interpreter, which the PEX need hold no distributions for. The
-        # caller passes the distributions it resolved for the target instead.
-        activated_dists=(
-            tuple(activated_dists) if activated_dists is not None else tuple(pex.resolve())
-        ),
+        activated_dists=activated_dists,
         shebang=shebang,
         venv_python=venv_python,
         bin_path=bin_path,
--
2.55.0


From 8b25c46ab2317d735f6f20fdcface3a0bd3bc8d0 Mon Sep 17 00:00:00 2001
From: John Sirois <john.sirois@gmail.com>
Date: Thu, 17 Sep 2026 23:30:39 -0700
Subject: [PATCH 2/2] Fix test - psutil 5.9.5 has no aarch64 wheels for Linux
 test.

The resulting yolo build using the local interpreter netted native wheels
not compatible with the foreign platform.
---
 tests/integration/cli/commands/test_venv_create.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/integration/cli/commands/test_venv_create.py b/tests/integration/cli/commands/test_venv_create.py
index cd235484..cde00c23 100644
--- a/tests/integration/cli/commands/test_venv_create.py
+++ b/tests/integration/cli/commands/test_venv_create.py
@@ -649,7 +649,7 @@ def test_foreign_target_link_python_from_pex_repository(
     foreign_platform = cross_arch_platform(3, 10)
     pex_repository = tmpdir.join("psutil.pex")
     run_pex_command(
-        args=["psutil==5.9.5", "--platform", foreign_platform, "-o", pex_repository]
+        args=["psutil==7.2.2", "--platform", foreign_platform, "-o", pex_repository]
     ).assert_success()

     venv_dir = tmpdir.join("venv")
--
2.55.0

[jsirois]

@jasonwbarnett please try out https://github.com/pex-tool/pex/releases/tag/v2.103.2 and close this PR if it meets your needs.