Handle situation where a specified jounal is not found.

features/data/configs/multiple_without_default.json

@@ -0,0 +1,16 @@
+{
+  "default_hour": 9,
+  "timeformat": "%Y-%m-%d %H:%M",
+  "linewrap": 80,
+  "encrypt": false,
+  "editor": "",
+  "default_minute": 0,
+  "highlight": true,
+  "password": "",
+  "journals": {
+    "simple": "features/journals/simple.journal",
+    "work": "features/journals/work.journal",
+    "ideas": "features/journals/nothing.journal"
+  },
+  "tagsymbols": "@"
+}

features/multiple_journals.feature

@@ -34,3 +34,8 @@ Feature: Multiple journals
         Then journal "ideas" should not exist
         When we run "jrnl ideas 23 july 2012: sell my junk on ebay and make lots of money"
         Then journal "ideas" should have 1 entry
+
+   Scenario: Gracefully handle a config without a default journal
+        Given we use the config "multiple_without_default.json"
+        When we run "jrnl fork this repo and fix something"
+        Then we should see the message "You have not specified a journal. Either provide a default journal in your config file, or specify one of your journals on the command line."

jrnl/cli.py

@@ -156,6 +156,11 @@ def run(manual_args=None):
         config.update(journal_conf)
     else:  # But also just give them a string to point to the journal file
         config['journal'] = journal_conf
+
+    if config['journal'] is None:
+        util.prompt("You have not specified a journal. Either provide a default journal in your config file, or specify one of your journals on the command line.")
+        sys.exit(1)
+
     config['journal'] = os.path.expanduser(os.path.expandvars(config['journal']))
     touch_journal(config['journal'])
     mode_compose, mode_export = guess_mode(args, config)