Report the whole build failure, not just its first line for classic (non-Vite) blueprint

CHANGELOG.md

@@ -1,3 +1,12 @@
+main
+------
+
+* Report the whole `ember build` failure in the `EmberCli::BuildError`
+  message, instead of only its first line. The line naming the file that
+  failed to build is rarely the first one the build tool writes, so a parse
+  error was reported with its message and line number but no way to tell
+  which file it came from
+
 0.14.0
 ------
 

lib/ember_cli/build_monitor.rb

@@ -41,6 +41,7 @@ def error_file_exists?
 
     def build_errors
       error_lines.
+        map(&:chomp).
         reject { |line| is_blank_or_backtrace?(line) }.
         reject { |line| is_deprecation_warning?(line) }.
         reject { |line| is_building_notice?(line) }
@@ -75,11 +76,11 @@ def error_file
     end
 
     def raise_build_error!
-      backtrace = build_errors.first
-      message = "#{name.inspect} has failed to build: #{backtrace}"
+      errors = build_errors
+      message = "#{name.inspect} has failed to build: #{errors.join("\n")}"
 
       error = BuildError.new(message)
-      error.set_backtrace(backtrace)
+      error.set_backtrace(errors)
 
       fail error
     end

spec/lib/ember_cli/build_monitor_spec.rb

@@ -56,6 +56,62 @@
       end
     end
 
+    context "when the error file describes the file that failed to build" do
+      it "raises a BuildError reporting every line of the failure" do
+        error_file = error_file_with_contents(
+          [
+            "Build failed.",
+            "File: app/templates/application.hbs",
+            "Parse error on line 4:",
+            "    at AStackTrace",
+          ])
+        paths = build_paths(error_file)
+        monitor = EmberCli::BuildMonitor.new("app-name", paths)
+
+        expect { monitor.check! }.
+          to raise_error(
+            EmberCli::BuildError,
+            %{"app-name" has failed to build: Build failed.\nFile: app/templates/application.hbs\nParse error on line 4:},
+          )
+      end
+
+      it "sets the backtrace to the lines of the failure" do
+        error_file = error_file_with_contents(
+          [
+            "File: app/templates/application.hbs",
+            "Parse error on line 4:",
+          ])
+        paths = build_paths(error_file)
+        monitor = EmberCli::BuildMonitor.new("app-name", paths)
+
+        expect { monitor.check! }.to raise_error(EmberCli::BuildError) do |error|
+          expect(error.backtrace).to eq(
+            [
+              "File: app/templates/application.hbs",
+              "Parse error on line 4:",
+            ])
+        end
+      end
+    end
+
+    context "when the error file's lines end in newlines" do
+      it "raises a BuildError without the trailing newlines" do
+        error_file = error_file_with_contents(
+          [
+            "File: app/templates/application.hbs\n",
+            "Parse error on line 4:\n",
+          ])
+        paths = build_paths(error_file)
+        monitor = EmberCli::BuildMonitor.new("app-name", paths)
+
+        expect { monitor.check! }.
+          to raise_error(
+            EmberCli::BuildError,
+            %{"app-name" has failed to build: File: app/templates/application.hbs\nParse error on line 4:},
+          )
+      end
+    end
+
     context "when the error file only contains deprecation warnings" do
       it "does not raise a BuildError" do
         error_file = error_file_with_contents(