Remove the baseline test new-year race condition. Fix #3723. (#3724)

* Patch the baseline test new-year race condition. Fix #3723.

* Use freezegun to circumvent the new year race condition.

.gitignore

@@ -5,7 +5,10 @@
 tmp/
 cache/
 output/
+baseline/
+nikola-baseline-build/
 /tags
+v3.*.zip.*
 
 # GitHub token
 .pypt/gh-token

nikola/__main__.py

@@ -116,6 +116,17 @@ def main(args=None):
     else:
         needs_config_file = False
 
+    invariant = False
+
+    if len(args) > 0 and args[0] == 'build' and '--invariant' in args:
+        try:
+            import freezegun
+            freeze = freezegun.freeze_time("2038-01-01")
+            freeze.start()
+            invariant = True
+        except ImportError:
+            req_missing(['freezegun'], 'perform invariant builds')
+
     sys.path.insert(0, os.path.dirname(conf_filename))
     try:
         spec = importlib.util.spec_from_file_location("conf", conf_filename)
@@ -138,17 +149,6 @@ def main(args=None):
     if conf_filename_changed:
         LOGGER.info("Using config file '{0}'".format(conf_filename))
 
-    invariant = False
-
-    if len(args) > 0 and args[0] == 'build' and '--invariant' in args:
-        try:
-            import freezegun
-            freeze = freezegun.freeze_time("2038-01-01")
-            freeze.start()
-            invariant = True
-        except ImportError:
-            req_missing(['freezegun'], 'perform invariant builds')
-
     if config:
         if os.path.isdir('plugins') and not os.path.exists('plugins/__init__.py'):
             with open('plugins/__init__.py', 'w') as fh:

scripts/baseline.sh

@@ -1,4 +1,7 @@
 #!/bin/bash
+
+set -e -o pipefail -x
+
 PYVER=$(scripts/getpyver.py short)
 if [[ "$1" == "check" ]]; then
     echo -e "\033[36m>> Downloading baseline for $PYVER...\033[0m"
@@ -19,8 +22,7 @@ rm "pages/creating-a-theme.rst" "pages/extending.rst" "pages/internals.rst" "pag
 LC_ALL='en_US.UTF-8' PYTHONHASHSEED=0 nikola build --invariant
 if [[ "$1" == "check" ]]; then
     echo -e "\033[36m>> Testing baseline...\033[0m"
-    diff -ubwr ../baseline output
-    if [[ $? == 0 ]]; then
+    if diff -ubwr ../baseline output; then
         echo -e "\033[32;1m>> Baseline test successful\033[0m"
     else
         CODE=$?