Rename confusing PYPY_* variables (#1044)

Since these variables refer to the latest version of PyPy, compared to
the similarly named `PYPY27` and `PYPY36` variables (ie same name except
without the underscore) which refer to the major/minor version only.

The similar names caused me to use the wrong one locally whilst working
on another PR, which was caught by tests but demonstrates why we should
rename them.

Closes @W-7935256@.

[skip changelog]

bin/default_pythons

@@ -12,5 +12,5 @@ LATEST_36="python-3.6.11"
 LATEST_35="python-3.5.9"
 LATEST_34="python-3.4.10"
 LATEST_27="python-2.7.18"
-PYPY_36="pypy3.6-7.3.1"
-PYPY_27="pypy2.7-7.3.1"
+LATEST_PYPY_36="pypy3.6-7.3.1"
+LATEST_PYPY_27="pypy2.7-7.3.1"

bin/steps/python

@@ -64,15 +64,15 @@ if curl --output /dev/null --silent --head --fail "$VENDORED_PYTHON"; then
   fi
   if [[ "$PYTHON_VERSION" == $PYPY27* ]]; then
     # security update note
-    if [ "$PYTHON_VERSION" != "$PYPY_27" ]; then
-      puts-warn "$SECURITY_UPDATE_PYPY" "$PYPY_27"
+    if [ "$PYTHON_VERSION" != "$LATEST_PYPY_27" ]; then
+      puts-warn "$SECURITY_UPDATE_PYPY" "$LATEST_PYPY_27"
       echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
     fi
   fi
   if [[ "$PYTHON_VERSION" == $PYPY36* ]]; then
     # security update note
-    if [ "$PYTHON_VERSION" != "$PYPY_36" ]; then
-      puts-warn "$SECURITY_UPDATE_PYPY" "$PYPY_36"
+    if [ "$PYTHON_VERSION" != "$LATEST_PYPY_36" ]; then
+      puts-warn "$SECURITY_UPDATE_PYPY" "$LATEST_PYPY_36"
       echo "       Learn More: https://devcenter.heroku.com/articles/python-runtimes"
     fi
   fi

test/run-versions

@@ -199,7 +199,7 @@ testPypy3_6() {
   compile "pypy3_6"
   assertCaptured "Installing pypy"
   assertNotCaptured "security update"
-  assertCaptured "$PYPY_36"
+  assertCaptured "$LATEST_PYPY_36"
   assertCaptured "Installing pip 20.1.1, setuptools 47.1.1 and wheel 0.34.2"
   assertCapturedSuccess
 }
@@ -211,7 +211,7 @@ testPypy3_6_warn() {
   else
     assertCaptured "Installing pypy"
     assertCaptured "security update!"
-    assertCaptured "$PYPY_36"
+    assertCaptured "$LATEST_PYPY_36"
     assertCapturedSuccess
   fi
 }
@@ -220,7 +220,7 @@ testPypy2_7() {
   compile "pypy2_7"
   assertCaptured "Installing pypy"
   assertNotCaptured "security update"
-  assertCaptured "$PYPY_27"
+  assertCaptured "$LATEST_PYPY_27"
   assertCaptured "Installing pip 20.1.1, setuptools 44.1.1 and wheel 0.34.2"
   assertCapturedSuccess
 }
@@ -232,7 +232,7 @@ testPypy2_7_warn() {
   else
     assertCaptured "Installing pypy"
     assertCaptured "security update!"
-    assertCaptured "$PYPY_27"
+    assertCaptured "$LATEST_PYPY_27"
     assertCapturedSuccess
   fi
 }