Cleanup environment variables

build_utils/release_tox.ini

@@ -11,25 +11,29 @@ test_command = python {toxinidir}/../tests_and_analysis/test/run_tests.py --repo
 requirements_dir = {toxinidir}/../tests_and_analysis
 passenv =
     EUPHONIC_VERSION
-    CC_LD
-setenv =
-    EXTRAS=[test,matplotlib,phonopy-reader,brille]
+# The name "extras" is reserved and has its own format with newlines:
+# we need a token to inject into custom commands_pre, so call it extras_str
+extras_str = [test,matplotlib,phonopy-reader,brille]
 
 # Test PyPI source distribution
 [testenv:pypisource-{py310,py312}]
-passenv = CC, CC_LD, LDFLAGS, CPPFLAGS
+passenv =
+    CC
+    CC_LD
+    LDFLAGS
+    CPPFLAGS
 commands_pre =
     python -m pip install \
     --force-reinstall \
-    'euphonic{env:EXTRAS}=={env:EUPHONIC_VERSION}' \
+    euphonic{[testenv]extras_str}=={env:EUPHONIC_VERSION} \
     --no-binary 'euphonic'
 commands = {[testenv]test_command}
 
 [testenv:pypi-{py310,py311,py312}]
 commands_pre =
     python -m pip install \
     --force-reinstall \
-    'euphonic{env:EXTRAS}=={env:EUPHONIC_VERSION}' \
+    euphonic[{[testenv]extras}]=={env:EUPHONIC_VERSION} \
     --only-binary 'euphonic'
 commands = {[testenv]test_command}
 
@@ -42,7 +46,7 @@ commands_pre =
     python -m pip install --force-reinstall \
         -r{toxinidir}/../tests_and_analysis/minimum_euphonic_requirements.txt
     python -m pip install \
-    'euphonic{env:EXTRAS}=={env:EUPHONIC_VERSION}' \
+    'euphonic{[testenv]extras_str}=={env:EUPHONIC_VERSION}' \
     --only-binary 'euphonic'
 commands = {[testenv]test_command}