From e627190ac81914a28f91d91734622f6651520509 Mon Sep 17 00:00:00 2001
From: Sam Davies <sam@razeware.com>
Date: Tue, 28 Jul 2020 13:35:30 +0100
Subject: [PATCH] WEB-3513: Parsing errors in chapter metadata are now labelled
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We don't verify the metadata, but we do now add some location info
so that it's possible to tell which file has the problem—rather than
having to search through every single chapter to find the extra space
in the indentation...
---
 app/lib/linting/linter.rb           | 21 +++++++++++++++++++--
 app/lib/parser/error.rb             | 17 +++++++++++++++++
 app/lib/parser/markdown_metadata.rb |  8 +++++++-
 3 files changed, 43 insertions(+), 3 deletions(-)
 create mode 100644 app/lib/parser/error.rb

diff --git a/app/lib/linting/linter.rb b/app/lib/linting/linter.rb
index d88de75..61630f2 100644
--- a/app/lib/linting/linter.rb
+++ b/app/lib/linting/linter.rb
@@ -20,7 +20,7 @@ def lint(options: {})
       output
     end
 
-    def lint_with_ui(options:, show_ui: true) # rubocop:disable Metrics/MethodLength
+    def lint_with_ui(options:, show_ui: true) # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
       with_spinner(title: 'Checking {{bold:publish.yaml}} exists', show: show_ui) do
         check_publish_file_exists
       end
@@ -31,6 +31,11 @@ def lint_with_ui(options:, show_ui: true) # rubocop:disable Metrics/MethodLength
       end
       return unless annotations.blank?
 
+      with_spinner(title: 'Attempting to parse book', show: show_ui) do
+        book
+      end
+      return unless annotations.blank?
+
       with_spinner(title: 'Validating image references', show: show_ui) do
         annotations.concat(Linting::ImageLinter.new(book: book).lint)
       end
@@ -78,11 +83,23 @@ def check_publish_file_exists
       false
     end
 
-    def book
+    def book # rubocop:disable Metrics/MethodLength
       @book ||= begin
         parser = Parser::Publish.new(file: file)
         parser.parse
       end
+    rescue Parser::Error => e
+      line_number = (e.message.match(/at line (\d+)/)&.captures&.first&.to_i || 0) + 1
+      annotations.push(
+        Annotation.new(
+          absolute_path: e.file,
+          annotation_level: 'failure',
+          start_line: line_number,
+          end_line: line_number,
+          message: e.message,
+          title: 'Unable to parse book.'
+        )
+      )
     end
   end
 end
diff --git a/app/lib/parser/error.rb b/app/lib/parser/error.rb
new file mode 100644
index 0000000..d6e66be
--- /dev/null
+++ b/app/lib/parser/error.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+module Parser
+  # An error for capturing parsing issues
+  class Error < StandardError
+    attr_reader :file
+
+    def initialize(file:, error: nil, msg: nil)
+      message = "There was a problem parsing #{file}"
+      message += "\n#{error.class.name}\n#{error.message}" if error.present?
+      message += "\n#{msg}" if msg.present?
+
+      super(message)
+      @file = file
+    end
+  end
+end
diff --git a/app/lib/parser/markdown_metadata.rb b/app/lib/parser/markdown_metadata.rb
index aa7ef55..84b1f38 100644
--- a/app/lib/parser/markdown_metadata.rb
+++ b/app/lib/parser/markdown_metadata.rb
@@ -12,7 +12,13 @@ def extract_metadata
     end
 
     def metadata
-      @metadata ||= Psych.load(extract_metadata).deep_symbolize_keys
+      @metadata ||= begin
+        Psych.load(extract_metadata, symbolize_names: true).tap do |metadata|
+          raise Parser::Error.new(file: path, msg: 'Unable to locate metadata at the top of the markdown') unless metadata.present?
+        end
+      end
+    rescue Psych::SyntaxError => e
+      raise Parser::Error.new(file: path, error: e)
     end
 
     def simple_attributes