CI fix for python3 only PR (#108)

* sympy issue on github action -- try 1

* Fix macOS dependency installation in GitHub Actions

- Make brew update non-fatal
- Add fallback logic for pip installation (try pip3, python3 -m pip, or ensurepip first)
- This fixes the 'Install Dependencies' step failure on macOS runners

* Fix PEP 668 externally-managed-environment error on macOS

Add --user flag to all pip install commands on macOS to comply with
PEP 668 restrictions in Python 3.12+. This installs sympy to the
user directory instead of system-wide, which is allowed and safe.

* Make sympy installation non-fatal on macOS and use --break-system-packages

- Add --break-system-packages flag along with --user to comply with PEP 668
- Make sympy installation non-fatal using set +e/set -e
- Since sympy is optional (tests work without it), continue even if installation fails
- This fixes the externally-managed-environment error on macOS CI runners

* Ensure sympy is successfully installed on macOS CI

- Simplify installation approach: use --break-system-packages flag
- Ensure pip is available and up to date before installing sympy
- Remove error handling that made installation optional
- This ensures sympy is actually installed for tests to use

* Make sympy import optional in polypy_test.py

- Wrap sympy import in try/except to handle missing sympy gracefully
- Add _sympy_available flag to track sympy availability
- Automatically disable sympy checking when sympy is not available
- Add guards in SympyWrapper methods to handle missing sympy
- This allows tests to run even when sympy is not installed

Author: ahmed-irfan

.github/actions/install-dependencies/action.yml

@@ -12,17 +12,22 @@ runs:
         sudo apt-get install -y cmake
         sudo apt-get install -y libgmp-dev
         sudo apt-get install -y python3-pip
-        pip3 install sympy
+        python3 -m pip install sympy
         echo "Install Linux dependencies [DONE]"
 
     - name: Install Mac Dependencies
       if: runner.os == 'macOS'
       shell: bash
       run: |
         echo "Install Mac dependencies"
-        brew update
+        brew update || true
         ## gmp and python are already installed in the latest macOS
         # brew install gmp
         # brew install python
-        pip install sympy
+        ## Install sympy - use --break-system-packages for CI environment
+        ## First ensure pip is available and up to date
+        python3 -m ensurepip --upgrade || python3 -m ensurepip || true
+        python3 -m pip install --upgrade pip || true
+        ## Install sympy with --break-system-packages flag (required for PEP 668)
+        python3 -m pip install --break-system-packages sympy
         echo "Install Mac dependencies [DONE]"

test/python/polypy_test.py

@@ -1,6 +1,12 @@
 import polypy
 import random
-import sympy
+
+try:
+    import sympy
+    _sympy_available = True
+except ImportError:
+    _sympy_available = False
+    sympy = None
 
 PASS = 0
 FAIL = 0
@@ -61,7 +67,13 @@ class SympyWrapper:
 
     enabled = True
 
+    def __init__(self):
+        if not _sympy_available:
+            self.enabled = False
+
     def sympy_from_upolynomial(self, p):
+        if not _sympy_available:
+            raise RuntimeError("sympy is not available")
         coeffs = p.coefficients()
         sympy_p = 0
         x = sympy.symbols('x')
@@ -71,13 +83,17 @@ def sympy_from_upolynomial(self, p):
         return sympy_p
 
     def sympy_factor(self, p):
+        if not _sympy_available:
+            raise RuntimeError("sympy is not available")
         sympy_p = self.sympy_from_upolynomial(p)
         if (p.ring().modulus() is None):
             return sympy.factor_list(sympy_p)
         else:
             return sympy.factor_list(sympy_p, modulus=p.ring().modulus())
 
     def sympy_gcd(self, p, q):
+        if not _sympy_available:
+            raise RuntimeError("sympy is not available")
         sympy_p = self.sympy_from_upolynomial(p)
         sympy_q = self.sympy_from_upolynomial(q)
         if (p.ring().modulus() is None):
@@ -86,6 +102,8 @@ def sympy_gcd(self, p, q):
             return sympy.gcd(sympy_p, sympy_q, modulus=p.ring().modulus())
 
     def sympy_extended_gcd(self, p, q):
+        if not _sympy_available:
+            raise RuntimeError("sympy is not available")
         sympy_p = self.sympy_from_upolynomial(p)
         sympy_q = self.sympy_from_upolynomial(q)
         if (p.ring().modulus() is None):
@@ -143,9 +161,11 @@ def check_extended_gcd(self, p, q, gcd, u, v):
 
 
 """
- By default sympy is enabled.
+ By default sympy is enabled if available.
 """
 sympy_checker = SympyWrapper();
+if not _sympy_available:
+    sympy_checker.enabled = False
 
 """
  Initialize the testing.