From 4669f8941afc81ba5126831faa92b87e2524b135 Mon Sep 17 00:00:00 2001
From: blnicho <blnicho@sandia.gov>
Date: Fri, 12 Dec 2025 12:09:11 -0700
Subject: [PATCH 01/34] Add stricter pin on platformdirs in GHA win jobs

---
 .github/workflows/test_branches.yml    | 5 +++--
 .github/workflows/test_pr_and_main.yml | 5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/test_branches.yml b/.github/workflows/test_branches.yml
index e5af7e5cbe5..dcbc31cf9c1 100644
--- a/.github/workflows/test_branches.yml
+++ b/.github/workflows/test_branches.yml
@@ -376,9 +376,10 @@ jobs:
         echo "*** Install Pyomo dependencies ***"
         # For windows, cannot use newer setuptools because of APPSI compilation issues
         # There seems to be some specific problem with platformdirs 4.5.0
-        # on win 3.13/3.14 as of 2025-10-23
+        # on win 3.13/3.14 as of 2025-10-23 and platformdirs 4.5.1 on win/3.13
+        # as of 2025-12-12
         if test "${{matrix.TARGET}}" == 'win'; then
-            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0"
+            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs<4.5.0"
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)
diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 62814d904fa..675ea7326e0 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -429,9 +429,10 @@ jobs:
         echo "*** Install Pyomo dependencies ***"
         # For windows, cannot use newer setuptools because of APPSI compilation issues
         # There seems to be some specific problem with platformdirs 4.5.0
-        # on win 3.13/3.14 as of 2025-10-23
+        # on win 3.13/3.14 as of 2025-10-23 and platformdirs 4.5.1 on win/3.13
+        # as of 2025-12-12
         if test "${{matrix.TARGET}}" == 'win'; then
-            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0"
+            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs<4.5.0"
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)

From 3bc1db9486665293420e729654e27a6ff9b96937 Mon Sep 17 00:00:00 2001
From: blnicho <blnicho@sandia.gov>
Date: Fri, 12 Dec 2025 14:52:45 -0700
Subject: [PATCH 02/34] Exclude specific platformdirs versions instead of
 setting upper bound

---
 .github/workflows/test_branches.yml    | 2 +-
 .github/workflows/test_pr_and_main.yml | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_branches.yml b/.github/workflows/test_branches.yml
index dcbc31cf9c1..d094bcb61bd 100644
--- a/.github/workflows/test_branches.yml
+++ b/.github/workflows/test_branches.yml
@@ -379,7 +379,7 @@ jobs:
         # on win 3.13/3.14 as of 2025-10-23 and platformdirs 4.5.1 on win/3.13
         # as of 2025-12-12
         if test "${{matrix.TARGET}}" == 'win'; then
-            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs<4.5.0"
+            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1"
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)
diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 675ea7326e0..f25b847758a 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -432,7 +432,7 @@ jobs:
         # on win 3.13/3.14 as of 2025-10-23 and platformdirs 4.5.1 on win/3.13
         # as of 2025-12-12
         if test "${{matrix.TARGET}}" == 'win'; then
-            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs<4.5.0"
+            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1"
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)

From c7129091bfe234c9b2aeb13c1042a64beb8965a3 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Mon, 22 Dec 2025 11:39:12 -0700
Subject: [PATCH 03/34] Relax tolerances due to upstream changes

---
 pyomo/contrib/piecewise/tests/test_nonlinear_to_pwl.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/pyomo/contrib/piecewise/tests/test_nonlinear_to_pwl.py b/pyomo/contrib/piecewise/tests/test_nonlinear_to_pwl.py
index 48c36c017fb..491ba2f4069 100644
--- a/pyomo/contrib/piecewise/tests/test_nonlinear_to_pwl.py
+++ b/pyomo/contrib/piecewise/tests/test_nonlinear_to_pwl.py
@@ -602,7 +602,7 @@ def test_linear_model_tree_uniform(self):
             # pretty close to m.x, but we're a bit off because we don't have 0
             # as a breakpoint.
             0.9833360108369479 * m.x + 0.16663989163052034,
-            places=7,
+            places=6,
         )
 
     def test_linear_model_tree_random(self):
@@ -657,7 +657,7 @@ def test_linear_model_tree_random_auto_depth_tree(self):
             pwlf._simplices,
             [(0, 1), (1, 2), (2, 3), (3, 4), (4, 5), (5, 6), (6, 7), (7, 8)],
         )
-        self.assertEqual(
+        self.assertStructuredAlmostEqual(
             pwlf._points,
             [
                 (-10,),
@@ -670,6 +670,7 @@ def test_linear_model_tree_random_auto_depth_tree(self):
                 (2.15597,),
                 (10,),
             ],
+            places=4,
         )
         self.assertEqual(len(pwlf._linear_functions), 8)
         for i in range(3):
@@ -680,7 +681,7 @@ def test_linear_model_tree_random_auto_depth_tree(self):
             # pretty close to - m.x, but we're a bit off because we don't have 0
             # as a breakpoint.
             -0.9851979299618323 * m.x + 0.12006477080409184,
-            places=7,
+            places=6,
         )
         for i in range(4, 8):
             assertExpressionsEqual(self, pwlf._linear_functions[i](m.x), m.x)

From c244119cc8aefc10bf3a558ff7acec4667a7efa6 Mon Sep 17 00:00:00 2001
From: blnicho <blnicho@sandia.gov>
Date: Mon, 5 Jan 2026 17:50:51 -0700
Subject: [PATCH 04/34] Removing Python 3.14 pin and excluding pip version in
 win conda build

---
 .github/workflows/test_branches.yml    | 5 +++--
 .github/workflows/test_pr_and_main.yml | 8 ++++----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/test_branches.yml b/.github/workflows/test_branches.yml
index d094bcb61bd..99b69af738e 100644
--- a/.github/workflows/test_branches.yml
+++ b/.github/workflows/test_branches.yml
@@ -377,9 +377,10 @@ jobs:
         # For windows, cannot use newer setuptools because of APPSI compilation issues
         # There seems to be some specific problem with platformdirs 4.5.0
         # on win 3.13/3.14 as of 2025-10-23 and platformdirs 4.5.1 on win/3.13
-        # as of 2025-12-12
+        # as of 2025-12-12, pip 25.3 now packages the problematic platformdirs
+        # version so excluding that also.
         if test "${{matrix.TARGET}}" == 'win'; then
-            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1"
+            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1 pip!=25.3"
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)
diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index f25b847758a..aa4c306f570 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -93,8 +93,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        # FIXME: pinning to 3.14.0 until 3.14.1 is removed from runner tool cache
-        python: [ '3.10', 3.11, 3.12, 3.13, 3.14.0 ]
+        python: [ '3.10', 3.11, 3.12, 3.13, 3.14 ]
         other: [""]
         category: [""]
 
@@ -430,9 +429,10 @@ jobs:
         # For windows, cannot use newer setuptools because of APPSI compilation issues
         # There seems to be some specific problem with platformdirs 4.5.0
         # on win 3.13/3.14 as of 2025-10-23 and platformdirs 4.5.1 on win/3.13
-        # as of 2025-12-12
+        # as of 2025-12-12. pip 25.3 now packages the problematic platformdirs
+        # version so excluding that also.
         if test "${{matrix.TARGET}}" == 'win'; then
-            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1"
+            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1 pip!=25.3"
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)

From 0a1d2062e15f1a13101a897eda464f2ddeff6ffd Mon Sep 17 00:00:00 2001
From: blnicho <blnicho@sandia.gov>
Date: Mon, 5 Jan 2026 18:00:42 -0700
Subject: [PATCH 05/34] New typos version complains about 'bimap'

---
 .github/workflows/typos.toml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/workflows/typos.toml b/.github/workflows/typos.toml
index c58806ff71e..76bfe276dec 100644
--- a/.github/workflows/typos.toml
+++ b/.github/workflows/typos.toml
@@ -65,6 +65,8 @@ MCH = "MCH"
 # Ignore RO
 ro = "ro"
 RO = "RO"
+# Ignore bimap
+bimap = "bimap"
 # Ignore EOF - end of file
 EOF = "EOF"
 # Ignore lst as shorthand for list

From ea598d834aaa3c142b56dbc5e2f23610452e6146 Mon Sep 17 00:00:00 2001
From: blnicho <blnicho@sandia.gov>
Date: Mon, 5 Jan 2026 18:24:52 -0700
Subject: [PATCH 06/34] Debugging: checking pip version

---
 .github/workflows/test_branches.yml    | 1 +
 .github/workflows/test_pr_and_main.yml | 1 +
 2 files changed, 2 insertions(+)

diff --git a/.github/workflows/test_branches.yml b/.github/workflows/test_branches.yml
index 99b69af738e..d5962df02e0 100644
--- a/.github/workflows/test_branches.yml
+++ b/.github/workflows/test_branches.yml
@@ -455,6 +455,7 @@ jobs:
         echo ""
         echo "Installing packages only available on PyPI"
         if test -n "$PYPI_DEPENDENCIES"; then
+            python -m pip --version
             python -m pip install --cache-dir cache/pip $PYPI_DEPENDENCIES
         fi
         # remember this python interpreter
diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index aa4c306f570..2e5c3d2a0c4 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -507,6 +507,7 @@ jobs:
         echo ""
         echo "Installing packages only available on PyPI"
         if test -n "$PYPI_DEPENDENCIES"; then
+            python -m pip --version
             python -m pip install --cache-dir cache/pip $PYPI_DEPENDENCIES
         fi
         # remember this python interpreter

From e025fbdc9ab386b1112c53703ff9795b4a56176e Mon Sep 17 00:00:00 2001
From: blnicho <blnicho@sandia.gov>
Date: Mon, 5 Jan 2026 18:49:42 -0700
Subject: [PATCH 07/34] Debugging: checking pip and platformdirs

---
 .github/workflows/test_branches.yml    | 3 ++-
 .github/workflows/test_pr_and_main.yml | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_branches.yml b/.github/workflows/test_branches.yml
index d5962df02e0..1efbb894c2f 100644
--- a/.github/workflows/test_branches.yml
+++ b/.github/workflows/test_branches.yml
@@ -455,7 +455,8 @@ jobs:
         echo ""
         echo "Installing packages only available on PyPI"
         if test -n "$PYPI_DEPENDENCIES"; then
-            python -m pip --version
+            python -c "import pip; print(pip.__version__, pip.__file__)"
+            python -c "import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
             python -m pip install --cache-dir cache/pip $PYPI_DEPENDENCIES
         fi
         # remember this python interpreter
diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 2e5c3d2a0c4..f291ba65101 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -507,7 +507,8 @@ jobs:
         echo ""
         echo "Installing packages only available on PyPI"
         if test -n "$PYPI_DEPENDENCIES"; then
-            python -m pip --version
+            python -c "import pip; print(pip.__version__, pip.__file__)"
+            python -c "import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
             python -m pip install --cache-dir cache/pip $PYPI_DEPENDENCIES
         fi
         # remember this python interpreter

From 151d65ee91191fc781edea0e5a6375eeb28fdf55 Mon Sep 17 00:00:00 2001
From: Bethany Nicholson <blnicho@users.noreply.github.com>
Date: Tue, 6 Jan 2026 08:39:06 -0500
Subject: [PATCH 08/34] Debugging: set upper bound on pip

---
 .github/workflows/test_branches.yml    | 2 +-
 .github/workflows/test_pr_and_main.yml | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_branches.yml b/.github/workflows/test_branches.yml
index 1efbb894c2f..2940edfc70c 100644
--- a/.github/workflows/test_branches.yml
+++ b/.github/workflows/test_branches.yml
@@ -380,7 +380,7 @@ jobs:
         # as of 2025-12-12, pip 25.3 now packages the problematic platformdirs
         # version so excluding that also.
         if test "${{matrix.TARGET}}" == 'win'; then
-            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1 pip!=25.3"
+            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1 pip<25.0"
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)
diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index f291ba65101..d58caca91d4 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -432,7 +432,7 @@ jobs:
         # as of 2025-12-12. pip 25.3 now packages the problematic platformdirs
         # version so excluding that also.
         if test "${{matrix.TARGET}}" == 'win'; then
-            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1 pip!=25.3"
+            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1 pip<25.0"
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)

From f2820486f162519dbf93e8c21892381ead8fd008 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Tue, 6 Jan 2026 10:12:03 -0700
Subject: [PATCH 09/34] Adding addional debugging

---
 .github/workflows/test_pr_and_main.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index d58caca91d4..f3c2c69e1e6 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -508,6 +508,7 @@ jobs:
         echo "Installing packages only available on PyPI"
         if test -n "$PYPI_DEPENDENCIES"; then
             python -c "import pip; print(pip.__version__, pip.__file__)"
+            python -c "from pip._vendor import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
             python -c "import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
             python -m pip install --cache-dir cache/pip $PYPI_DEPENDENCIES
         fi

From 461d326ce1b12d2134bfb10bb838c7ab79cc0b12 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Tue, 6 Jan 2026 10:53:54 -0700
Subject: [PATCH 10/34] More debugging

---
 .github/workflows/test_pr_and_main.yml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index f3c2c69e1e6..ebe3ff67b56 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -507,6 +507,9 @@ jobs:
         echo ""
         echo "Installing packages only available on PyPI"
         if test -n "$PYPI_DEPENDENCIES"; then
+            python -c "import ctypes; print(ctypes.__path__)"
+            python -c "import ctypes.windll"
+            find `python -c "import os.path, ctypes; print(os.path.dirname(ctypes.__path__))"`
             python -c "import pip; print(pip.__version__, pip.__file__)"
             python -c "from pip._vendor import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
             python -c "import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"

From 9207610f3be40c754691228294a040969c2e27f4 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Tue, 6 Jan 2026 11:50:39 -0700
Subject: [PATCH 11/34] More debugging

---
 .github/workflows/test_pr_and_main.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index ebe3ff67b56..ef087302027 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -506,10 +506,10 @@ jobs:
         # Re-try Pyomo (optional) dependencies with pip
         echo ""
         echo "Installing packages only available on PyPI"
+        conda install -q -y --force-reinstall libffi
         if test -n "$PYPI_DEPENDENCIES"; then
+            find `python -c "import os, os.path; print(os.path.dirname(os.__path__))"` -name \*conda_trash
             python -c "import ctypes; print(ctypes.__path__)"
-            python -c "import ctypes.windll"
-            find `python -c "import os.path, ctypes; print(os.path.dirname(ctypes.__path__))"`
             python -c "import pip; print(pip.__version__, pip.__file__)"
             python -c "from pip._vendor import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
             python -c "import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"

From 1a5fb2f93da25dc892c359994244c7dfcfb79e28 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Tue, 6 Jan 2026 12:12:56 -0700
Subject: [PATCH 12/34] Fix debugging

---
 .github/workflows/test_pr_and_main.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index ef087302027..b270dc5a61b 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -509,7 +509,7 @@ jobs:
         conda install -q -y --force-reinstall libffi
         if test -n "$PYPI_DEPENDENCIES"; then
             find `python -c "import os, os.path; print(os.path.dirname(os.__path__))"` -name \*conda_trash
-            python -c "import ctypes; print(ctypes.__path__)"
+            python -c "import ctypes; print(ctypes.__file__)"
             python -c "import pip; print(pip.__version__, pip.__file__)"
             python -c "from pip._vendor import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
             python -c "import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"

From 0479e8f0c0c682ee56198f704543220d839451d0 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Tue, 6 Jan 2026 12:33:03 -0700
Subject: [PATCH 13/34] Debug: fix path query

---
 .github/workflows/test_pr_and_main.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index b270dc5a61b..a0dd9d714e6 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -508,7 +508,7 @@ jobs:
         echo "Installing packages only available on PyPI"
         conda install -q -y --force-reinstall libffi
         if test -n "$PYPI_DEPENDENCIES"; then
-            find `python -c "import os, os.path; print(os.path.dirname(os.__path__))"` -name \*conda_trash
+            find `python -c "import os, os.path; print(os.path.dirname(os.__file__))"` -name \*conda_trash
             python -c "import ctypes; print(ctypes.__file__)"
             python -c "import pip; print(pip.__version__, pip.__file__)"
             python -c "from pip._vendor import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"

From 0a9003cba3ca55a40ad86a026b75cfc4c6a4be29 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Tue, 6 Jan 2026 13:25:30 -0700
Subject: [PATCH 14/34] Debug: force reinstall python and libffi

---
 .github/workflows/test_pr_and_main.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index a0dd9d714e6..c79050b07b4 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -506,7 +506,7 @@ jobs:
         # Re-try Pyomo (optional) dependencies with pip
         echo ""
         echo "Installing packages only available on PyPI"
-        conda install -q -y --force-reinstall libffi
+        conda install -q -y --force-reinstall libffi python
         if test -n "$PYPI_DEPENDENCIES"; then
             find `python -c "import os, os.path; print(os.path.dirname(os.__file__))"` -name \*conda_trash
             python -c "import ctypes; print(ctypes.__file__)"

From 327e0b830bd4d43c8a078c7c9c52214c1e0b37b4 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Tue, 6 Jan 2026 13:53:36 -0700
Subject: [PATCH 15/34] Debug: pin libffi

---
 .github/workflows/test_pr_and_main.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index c79050b07b4..6a7a014e4f3 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -432,7 +432,7 @@ jobs:
         # as of 2025-12-12. pip 25.3 now packages the problematic platformdirs
         # version so excluding that also.
         if test "${{matrix.TARGET}}" == 'win'; then
-            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1 pip<25.0"
+            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1 libffi<3.5"
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)
@@ -509,6 +509,7 @@ jobs:
         conda install -q -y --force-reinstall libffi python
         if test -n "$PYPI_DEPENDENCIES"; then
             find `python -c "import os, os.path; print(os.path.dirname(os.__file__))"` -name \*conda_trash
+            ls -l "C:\Miniconda\envs\test\Lib\ctypes"
             python -c "import ctypes; print(ctypes.__file__)"
             python -c "import pip; print(pip.__version__, pip.__file__)"
             python -c "from pip._vendor import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"

From ec201511cd3740755240b2c9124f1a6e78f1c0ff Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Tue, 6 Jan 2026 14:20:48 -0700
Subject: [PATCH 16/34] Debug: add dir listings

---
 .github/workflows/test_pr_and_main.yml | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 6a7a014e4f3..3dfe4542a80 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -506,10 +506,17 @@ jobs:
         # Re-try Pyomo (optional) dependencies with pip
         echo ""
         echo "Installing packages only available on PyPI"
+        find `python -c "import os, os.path; print(os.path.dirname(os.__file__))"` -name '*.conda_trash'
+        echo "LS LIB"
+        ls -l C:\\Miniconda\\envs\\test\\Lib\\*
+        echo "LS LIB/CTYPES"
+        ls -l C:\\Miniconda\\envs\\test\\Lib\\ctypes\\*
         conda install -q -y --force-reinstall libffi python
+        echo "LS LIB"
+        ls -l C:\\Miniconda\\envs\\test\\Lib\\*
+        echo "LS LIB/CTYPES"
+        ls -l C:\\Miniconda\\envs\\test\\Lib\\ctypes\\*
         if test -n "$PYPI_DEPENDENCIES"; then
-            find `python -c "import os, os.path; print(os.path.dirname(os.__file__))"` -name \*conda_trash
-            ls -l "C:\Miniconda\envs\test\Lib\ctypes"
             python -c "import ctypes; print(ctypes.__file__)"
             python -c "import pip; print(pip.__version__, pip.__file__)"
             python -c "from pip._vendor import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"

From db32bf0137a6c7865b5564571672345c3ba6470c Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Tue, 6 Jan 2026 14:58:54 -0700
Subject: [PATCH 17/34] Debug: change ls

---
 .github/workflows/test_pr_and_main.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 3dfe4542a80..3bc22d8d826 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -508,9 +508,9 @@ jobs:
         echo "Installing packages only available on PyPI"
         find `python -c "import os, os.path; print(os.path.dirname(os.__file__))"` -name '*.conda_trash'
         echo "LS LIB"
-        ls -l C:\\Miniconda\\envs\\test\\Lib\\*
+        ls -l `python -c "import os, os.path; print(os.path.dirname(os.__file__))"`
         echo "LS LIB/CTYPES"
-        ls -l C:\\Miniconda\\envs\\test\\Lib\\ctypes\\*
+        ls -l `python -c "import os, os.path; print(os.path.join(os.path.dirname(os.__file__), 'ctypes'))"`
         conda install -q -y --force-reinstall libffi python
         echo "LS LIB"
         ls -l C:\\Miniconda\\envs\\test\\Lib\\*

From 1be6355a64af1dab859c1d74aa7c9eccbd72dfd3 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 07:12:13 -0700
Subject: [PATCH 18/34] Debug: print the path

---
 .github/workflows/test_pr_and_main.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 3bc22d8d826..1567442002b 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -507,6 +507,8 @@ jobs:
         echo ""
         echo "Installing packages only available on PyPI"
         find `python -c "import os, os.path; print(os.path.dirname(os.__file__))"` -name '*.conda_trash'
+        pwd
+        ls /mnt
         echo "LS LIB"
         ls -l `python -c "import os, os.path; print(os.path.dirname(os.__file__))"`
         echo "LS LIB/CTYPES"

From bf01cb168f8a81fef3bd09b9fa9bee9bb216e46b Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 07:47:32 -0700
Subject: [PATCH 19/34] Debug: probe filesystem

---
 .github/workflows/test_pr_and_main.yml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 1567442002b..eeb204013df 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -367,6 +367,14 @@ jobs:
     - name: Install Python packages (conda)
       if: matrix.PYENV == 'conda'
       run: |
+        echo "LS /"
+        ls /
+        echo "LS /d"
+        ls /d
+        echo "LS /d/a"
+        ls /d/a
+        echo "LS /c"
+        ls /c
         # Set up environment
         conda config --set always_yes yes
         conda config --set auto_update_conda false

From f64f882f2a11125d2fb71403fbbf744fbc7a88e1 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 07:56:12 -0700
Subject: [PATCH 20/34] Debug: update dir probes

---
 .github/workflows/test_pr_and_main.yml | 25 ++++++++-----------------
 1 file changed, 8 insertions(+), 17 deletions(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index eeb204013df..69b53edbc27 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -367,14 +367,6 @@ jobs:
     - name: Install Python packages (conda)
       if: matrix.PYENV == 'conda'
       run: |
-        echo "LS /"
-        ls /
-        echo "LS /d"
-        ls /d
-        echo "LS /d/a"
-        ls /d/a
-        echo "LS /c"
-        ls /c
         # Set up environment
         conda config --set always_yes yes
         conda config --set auto_update_conda false
@@ -516,16 +508,15 @@ jobs:
         echo "Installing packages only available on PyPI"
         find `python -c "import os, os.path; print(os.path.dirname(os.__file__))"` -name '*.conda_trash'
         pwd
-        ls /mnt
-        echo "LS LIB"
-        ls -l `python -c "import os, os.path; print(os.path.dirname(os.__file__))"`
-        echo "LS LIB/CTYPES"
-        ls -l `python -c "import os, os.path; print(os.path.join(os.path.dirname(os.__file__), 'ctypes'))"`
+        echo "LS /c/Miniconda/envs/test"
+        ls /c/Miniconda/envs/test
+        echo "LS /c/Miniconda/envs/test/Lib"
+        ls /c/Miniconda/envs/test/Lib
+        echo "LS /c/Miniconda/envs/test/Lib/ctypes"
+        ls /c/Miniconda/envs/test/Lib/ctypes
         conda install -q -y --force-reinstall libffi python
-        echo "LS LIB"
-        ls -l C:\\Miniconda\\envs\\test\\Lib\\*
-        echo "LS LIB/CTYPES"
-        ls -l C:\\Miniconda\\envs\\test\\Lib\\ctypes\\*
+        echo "LS /c/Miniconda/envs/test/Lib/ctypes"
+        ls /c/Miniconda/envs/test/Lib/ctypes
         if test -n "$PYPI_DEPENDENCIES"; then
             python -c "import ctypes; print(ctypes.__file__)"
             python -c "import pip; print(pip.__version__, pip.__file__)"

From 222f4ee23b1d85079574821117c15221d174ad45 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 09:03:04 -0700
Subject: [PATCH 21/34] Debug: more dir listing

---
 .github/workflows/test_pr_and_main.yml | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 69b53edbc27..3d2c520bad3 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -398,6 +398,12 @@ jobs:
         conda list --show-channel-urls
         which python
         python --version
+        echo "LS /c/Miniconda/envs/test"
+        ls /c/Miniconda/envs/test
+        echo "LS /c/Miniconda/envs/test/Lib"
+        ls /c/Miniconda/envs/test/Lib
+        echo "LS /c/Miniconda/envs/test/Lib/ctypes"
+        ls /c/Miniconda/envs/test/Lib/ctypes
         # We need setuptools so we can run Pyomo's setup.py
         conda install setuptools
         # Note: some pypi packages are not available through conda
@@ -507,14 +513,13 @@ jobs:
         echo ""
         echo "Installing packages only available on PyPI"
         find `python -c "import os, os.path; print(os.path.dirname(os.__file__))"` -name '*.conda_trash'
-        pwd
         echo "LS /c/Miniconda/envs/test"
         ls /c/Miniconda/envs/test
         echo "LS /c/Miniconda/envs/test/Lib"
         ls /c/Miniconda/envs/test/Lib
         echo "LS /c/Miniconda/envs/test/Lib/ctypes"
         ls /c/Miniconda/envs/test/Lib/ctypes
-        conda install -q -y --force-reinstall libffi python
+        conda install -q -y --force-reinstall libffi python python-abi
         echo "LS /c/Miniconda/envs/test/Lib/ctypes"
         ls /c/Miniconda/envs/test/Lib/ctypes
         if test -n "$PYPI_DEPENDENCIES"; then

From 18cfa1d858633ad4a6662a904624dc0f6aeadc0d Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 09:37:21 -0700
Subject: [PATCH 22/34] Debug: check initial conda env

---
 .github/workflows/test_pr_and_main.yml | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 3d2c520bad3..bc94f14f2bd 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -404,6 +404,11 @@ jobs:
         ls /c/Miniconda/envs/test/Lib
         echo "LS /c/Miniconda/envs/test/Lib/ctypes"
         ls /c/Miniconda/envs/test/Lib/ctypes
+        python -c "import ctypes; print(ctypes.__file__)"
+        python -c "import ctypes.windll; print(ctypes.windll.__file__)"
+        python -c "import pip; print(pip.__version__, pip.__file__)"
+        python -c "from pip._vendor import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
+        python -c "import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
         # We need setuptools so we can run Pyomo's setup.py
         conda install setuptools
         # Note: some pypi packages are not available through conda
@@ -519,7 +524,7 @@ jobs:
         ls /c/Miniconda/envs/test/Lib
         echo "LS /c/Miniconda/envs/test/Lib/ctypes"
         ls /c/Miniconda/envs/test/Lib/ctypes
-        conda install -q -y --force-reinstall libffi python python-abi
+        conda install -q -y --force-reinstall libffi python python_abi
         echo "LS /c/Miniconda/envs/test/Lib/ctypes"
         ls /c/Miniconda/envs/test/Lib/ctypes
         if test -n "$PYPI_DEPENDENCIES"; then

From 44e31965ad7cec6660116ae8ecf10953e71b5cae Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 09:43:10 -0700
Subject: [PATCH 23/34] Debug: remove debugging

---
 .github/workflows/test_pr_and_main.yml | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index bc94f14f2bd..a72041be366 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -398,17 +398,6 @@ jobs:
         conda list --show-channel-urls
         which python
         python --version
-        echo "LS /c/Miniconda/envs/test"
-        ls /c/Miniconda/envs/test
-        echo "LS /c/Miniconda/envs/test/Lib"
-        ls /c/Miniconda/envs/test/Lib
-        echo "LS /c/Miniconda/envs/test/Lib/ctypes"
-        ls /c/Miniconda/envs/test/Lib/ctypes
-        python -c "import ctypes; print(ctypes.__file__)"
-        python -c "import ctypes.windll; print(ctypes.windll.__file__)"
-        python -c "import pip; print(pip.__version__, pip.__file__)"
-        python -c "from pip._vendor import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
-        python -c "import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
         # We need setuptools so we can run Pyomo's setup.py
         conda install setuptools
         # Note: some pypi packages are not available through conda

From 9369bd47e9f1857deb28f4b4a0bd49912a462232 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 10:04:27 -0700
Subject: [PATCH 24/34] Debug: check ctypes earlier

---
 .github/workflows/test_pr_and_main.yml | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index a72041be366..aeb2dc4f90d 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -368,6 +368,7 @@ jobs:
       if: matrix.PYENV == 'conda'
       run: |
         # Set up environment
+        python -c "import ctypes; print(ctypes.__file__)"
         conda config --set always_yes yes
         conda config --set auto_update_conda false
         conda config --set channel_priority strict
@@ -386,6 +387,7 @@ jobs:
                 conda config --set solver libmamba
             fi
         fi
+        python -c "import ctypes; print(ctypes.__file__)"
         # Add the rest of the channels
         conda config --append channels gurobi
         conda config --append channels ibmdecisionoptimization
@@ -506,16 +508,8 @@ jobs:
         # Re-try Pyomo (optional) dependencies with pip
         echo ""
         echo "Installing packages only available on PyPI"
-        find `python -c "import os, os.path; print(os.path.dirname(os.__file__))"` -name '*.conda_trash'
-        echo "LS /c/Miniconda/envs/test"
-        ls /c/Miniconda/envs/test
-        echo "LS /c/Miniconda/envs/test/Lib"
-        ls /c/Miniconda/envs/test/Lib
-        echo "LS /c/Miniconda/envs/test/Lib/ctypes"
-        ls /c/Miniconda/envs/test/Lib/ctypes
+        find /c/Miniconda/envs/test/Lib -name '*.conda_trash'
         conda install -q -y --force-reinstall libffi python python_abi
-        echo "LS /c/Miniconda/envs/test/Lib/ctypes"
-        ls /c/Miniconda/envs/test/Lib/ctypes
         if test -n "$PYPI_DEPENDENCIES"; then
             python -c "import ctypes; print(ctypes.__file__)"
             python -c "import pip; print(pip.__version__, pip.__file__)"

From 14d759554a54b39200d6d9a904fa28974462e4d8 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 11:23:27 -0700
Subject: [PATCH 25/34] Debug: locate where ctypes starts failing

---
 .github/workflows/test_pr_and_main.yml | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index aeb2dc4f90d..6b6266d2679 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -368,7 +368,7 @@ jobs:
       if: matrix.PYENV == 'conda'
       run: |
         # Set up environment
-        python -c "import ctypes; print(ctypes.__file__)"
+        python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         conda config --set always_yes yes
         conda config --set auto_update_conda false
         conda config --set channel_priority strict
@@ -387,7 +387,7 @@ jobs:
                 conda config --set solver libmamba
             fi
         fi
-        python -c "import ctypes; print(ctypes.__file__)"
+        python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         # Add the rest of the channels
         conda config --append channels gurobi
         conda config --append channels ibmdecisionoptimization
@@ -402,6 +402,7 @@ jobs:
         python --version
         # We need setuptools so we can run Pyomo's setup.py
         conda install setuptools
+        python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         # Note: some pypi packages are not available through conda
         PYOMO_DEPENDENCIES=`python setup.py dependencies \
             --extras "$EXTRAS" | tail -1`
@@ -439,6 +440,7 @@ jobs:
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)
         conda install --update-deps -q -y python="${{matrix.python}}" $CONDA_DEPENDENCIES
+        python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         if test -z "${{matrix.slim}}"; then
             # xpress.init() (xpress 9.5.1 from conda) hangs indefinitely
             # on GHA/Windows under Python 3.10 and 3.11.  Exclude that
@@ -498,6 +500,7 @@ jobs:
                         kill $timeout_pid 2>/dev/null \
                             || echo "TIMEOUT: time limit expired"
                     fi
+                    python -c "import ctypes; print('CTYPES', ctypes.__file__)"
                 fi
                 echo ""
                 if test -z "$_BUILDS"; then
@@ -508,6 +511,7 @@ jobs:
         # Re-try Pyomo (optional) dependencies with pip
         echo ""
         echo "Installing packages only available on PyPI"
+        python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         find /c/Miniconda/envs/test/Lib -name '*.conda_trash'
         conda install -q -y --force-reinstall libffi python python_abi
         if test -n "$PYPI_DEPENDENCIES"; then

From f3a239188a5cf4f551143153a3cd28c44196c911 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 11:39:32 -0700
Subject: [PATCH 26/34] Debug: remove --update-deps

---
 .github/workflows/test_pr_and_main.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 6b6266d2679..68d674863cd 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -439,7 +439,8 @@ jobs:
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)
-        conda install --update-deps -q -y python="${{matrix.python}}" $CONDA_DEPENDENCIES
+        # Note: remove '--update-deps' to prevent update that breaks ctypes
+        conda install -q -y python="${{matrix.python}}" $CONDA_DEPENDENCIES
         python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         if test -z "${{matrix.slim}}"; then
             # xpress.init() (xpress 9.5.1 from conda) hangs indefinitely

From 525b0995188037e59bb13af92f392e0072e525a2 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 11:50:41 -0700
Subject: [PATCH 27/34] Debug: remove libffi spec

---
 .github/workflows/test_pr_and_main.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 68d674863cd..e072a2f51b5 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -435,7 +435,7 @@ jobs:
         # as of 2025-12-12. pip 25.3 now packages the problematic platformdirs
         # version so excluding that also.
         if test "${{matrix.TARGET}}" == 'win'; then
-            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1 libffi<3.5"
+            CONDA_DEPENDENCIES="$CONDA_DEPENDENCIES setuptools<74.0.0 platformdirs!=4.5.0,!=4.5.1"
         fi
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)

From bba121a1ef8f43e000c771b32aa8a005b6ebaa05 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 12:03:26 -0700
Subject: [PATCH 28/34] Debug: pin installed packages

---
 .github/workflows/test_pr_and_main.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index e072a2f51b5..7bd19d4c21d 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -440,7 +440,7 @@ jobs:
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)
         # Note: remove '--update-deps' to prevent update that breaks ctypes
-        conda install -q -y python="${{matrix.python}}" $CONDA_DEPENDENCIES
+        conda install -q -y --no-update-deps python="${{matrix.python}}" $CONDA_DEPENDENCIES
         python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         if test -z "${{matrix.slim}}"; then
             # xpress.init() (xpress 9.5.1 from conda) hangs indefinitely

From 2ec98d521c00f859af01c7d4dc06d92e54cab362 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 12:15:34 -0700
Subject: [PATCH 29/34] Debug: update conda install cmd

---
 .github/workflows/test_pr_and_main.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 7bd19d4c21d..20caaa70a45 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -440,7 +440,8 @@ jobs:
         # Note: this will fail the build if any installation fails (or
         # possibly if it outputs messages to stderr)
         # Note: remove '--update-deps' to prevent update that breaks ctypes
-        conda install -q -y --no-update-deps python="${{matrix.python}}" $CONDA_DEPENDENCIES
+        # Note: removed 'python="${{matrix.python}}"'... is it not necessary?
+        conda install -q -y --no-update-deps $CONDA_DEPENDENCIES
         python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         if test -z "${{matrix.slim}}"; then
             # xpress.init() (xpress 9.5.1 from conda) hangs indefinitely

From eadd8754b13847ad2389a92aedb450f92fbce0e5 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 13:34:11 -0700
Subject: [PATCH 30/34] Debug: explicitly pin libffi

---
 .github/workflows/test_pr_and_main.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 20caaa70a45..e6ca36c14e0 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -387,6 +387,8 @@ jobs:
                 conda config --set solver libmamba
             fi
         fi
+        # Pin libffi (updating it can break pip on windows)
+        conda config --env --append pinned_packages `conda list | grep libffi | sed -r 's/\s+(\S+).*/=\1/'`
         python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         # Add the rest of the channels
         conda config --append channels gurobi

From 5db443362ee1a6143ab9a1a16b8a19589414d1e5 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 13:57:24 -0700
Subject: [PATCH 31/34] Debug: explicitly update environment

---
 .github/workflows/test_pr_and_main.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index e6ca36c14e0..3abf90e0e49 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -387,6 +387,8 @@ jobs:
                 conda config --set solver libmamba
             fi
         fi
+        conda update --all
+        python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         # Pin libffi (updating it can break pip on windows)
         conda config --env --append pinned_packages `conda list | grep libffi | sed -r 's/\s+(\S+).*/=\1/'`
         python -c "import ctypes; print('CTYPES', ctypes.__file__)"

From 93462cb41a5262bc0b4b440c259afb08e1ddc618 Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 14:11:32 -0700
Subject: [PATCH 32/34] Debug: force reinstall pip

---
 .github/workflows/test_pr_and_main.yml | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 3abf90e0e49..4d44d2b1cd4 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -387,10 +387,9 @@ jobs:
                 conda config --set solver libmamba
             fi
         fi
-        conda update --all
         python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         # Pin libffi (updating it can break pip on windows)
-        conda config --env --append pinned_packages `conda list | grep libffi | sed -r 's/\s+(\S+).*/=\1/'`
+        # conda config --env --append pinned_packages `conda list | grep libffi | sed -r 's/\s+(\S+).*/=\1/'`
         python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         # Add the rest of the channels
         conda config --append channels gurobi
@@ -518,8 +517,8 @@ jobs:
         echo ""
         echo "Installing packages only available on PyPI"
         python -c "import ctypes; print('CTYPES', ctypes.__file__)"
-        find /c/Miniconda/envs/test/Lib -name '*.conda_trash'
-        conda install -q -y --force-reinstall libffi python python_abi
+        conda install -q -y --force-reinstall pip libffi python python_abi
+        find /c/Miniconda/envs/test -name '*.conda_trash'
         if test -n "$PYPI_DEPENDENCIES"; then
             python -c "import ctypes; print(ctypes.__file__)"
             python -c "import pip; print(pip.__version__, pip.__file__)"

From c222d197e3206a433128582f8354b503b7143cbe Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Wed, 7 Jan 2026 14:25:51 -0700
Subject: [PATCH 33/34] Debug: remove debugging

---
 .github/workflows/test_pr_and_main.yml | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 4d44d2b1cd4..13e8a62ff02 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -387,10 +387,6 @@ jobs:
                 conda config --set solver libmamba
             fi
         fi
-        python -c "import ctypes; print('CTYPES', ctypes.__file__)"
-        # Pin libffi (updating it can break pip on windows)
-        # conda config --env --append pinned_packages `conda list | grep libffi | sed -r 's/\s+(\S+).*/=\1/'`
-        python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         # Add the rest of the channels
         conda config --append channels gurobi
         conda config --append channels ibmdecisionoptimization
@@ -405,7 +401,6 @@ jobs:
         python --version
         # We need setuptools so we can run Pyomo's setup.py
         conda install setuptools
-        python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         # Note: some pypi packages are not available through conda
         PYOMO_DEPENDENCIES=`python setup.py dependencies \
             --extras "$EXTRAS" | tail -1`
@@ -505,7 +500,6 @@ jobs:
                         kill $timeout_pid 2>/dev/null \
                             || echo "TIMEOUT: time limit expired"
                     fi
-                    python -c "import ctypes; print('CTYPES', ctypes.__file__)"
                 fi
                 echo ""
                 if test -z "$_BUILDS"; then
@@ -516,14 +510,8 @@ jobs:
         # Re-try Pyomo (optional) dependencies with pip
         echo ""
         echo "Installing packages only available on PyPI"
-        python -c "import ctypes; print('CTYPES', ctypes.__file__)"
         conda install -q -y --force-reinstall pip libffi python python_abi
-        find /c/Miniconda/envs/test -name '*.conda_trash'
         if test -n "$PYPI_DEPENDENCIES"; then
-            python -c "import ctypes; print(ctypes.__file__)"
-            python -c "import pip; print(pip.__version__, pip.__file__)"
-            python -c "from pip._vendor import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
-            python -c "import platformdirs; print(platformdirs.__version__, platformdirs.__file__)"
             python -m pip install --cache-dir cache/pip $PYPI_DEPENDENCIES
         fi
         # remember this python interpreter

From 9514228968592c56ec9f0d8f09cc1ad560d4ecea Mon Sep 17 00:00:00 2001
From: John Siirola <jsiirola@users.noreply.github.com>
Date: Thu, 8 Jan 2026 08:01:42 -0700
Subject: [PATCH 34/34] Debug: force reinstall of additional packages

---
 .github/workflows/test_pr_and_main.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test_pr_and_main.yml b/.github/workflows/test_pr_and_main.yml
index 13e8a62ff02..409303ea42e 100644
--- a/.github/workflows/test_pr_and_main.yml
+++ b/.github/workflows/test_pr_and_main.yml
@@ -510,7 +510,8 @@ jobs:
         # Re-try Pyomo (optional) dependencies with pip
         echo ""
         echo "Installing packages only available on PyPI"
-        conda install -q -y --force-reinstall pip libffi python python_abi
+        conda install -q -y --force-reinstall pip libffi python python_abi \
+            `conda list | grep -E 'zlib|^vc|^vs' | cut -d\  -f1`
         if test -n "$PYPI_DEPENDENCIES"; then
             python -m pip install --cache-dir cache/pip $PYPI_DEPENDENCIES
         fi