From eedf6760ad1046ef571ef1a37437ad34d3481e54 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stanis=C5=82aw=20Barzowski?= <stanislaw.barzowski@gmail.com>
Date: Thu, 18 Jan 2018 00:49:14 +0100
Subject: [PATCH] Convert non-string errors to string

---
 interpreter.go                       |  6 ++++++
 testdata/error_function_fail.golden  | 10 ++++++++++
 testdata/error_function_fail.jsonnet |  1 +
 testdata/error_object.golden         | 10 ++++++++++
 testdata/error_object.jsonnet        |  1 +
 5 files changed, 28 insertions(+)
 create mode 100644 testdata/error_function_fail.golden
 create mode 100644 testdata/error_function_fail.jsonnet
 create mode 100644 testdata/error_object.golden
 create mode 100644 testdata/error_object.jsonnet

diff --git a/interpreter.go b/interpreter.go
index 6d1e995..fd82c89 100644
--- a/interpreter.go
+++ b/interpreter.go
@@ -364,6 +364,12 @@ func (i *interpreter) evaluate(a ast.Node, tc tailCallStatus) (value, error) {
 			// error when evaluating error message
 			return nil, err
 		}
+		if msgVal.getType() != stringType {
+			msgVal, err = builtinToString(e, &readyValue{msgVal})
+			if err != nil {
+				return nil, err
+			}
+		}
 		msg, err := e.getString(msgVal)
 		if err != nil {
 			return nil, err
diff --git a/testdata/error_function_fail.golden b/testdata/error_function_fail.golden
new file mode 100644
index 0000000..56407c5
--- /dev/null
+++ b/testdata/error_function_fail.golden
@@ -0,0 +1,10 @@
+RUNTIME ERROR: Couldn't manifest function in JSON output.
+-------------------------------------------------
+	testdata/error_function_fail:1:1-22	$
+
+error (function(x) 42)
+
+-------------------------------------------------
+	During evaluation	
+
+
diff --git a/testdata/error_function_fail.jsonnet b/testdata/error_function_fail.jsonnet
new file mode 100644
index 0000000..79e4c7b
--- /dev/null
+++ b/testdata/error_function_fail.jsonnet
@@ -0,0 +1 @@
+error (function(x) 42)
\ No newline at end of file
diff --git a/testdata/error_object.golden b/testdata/error_object.golden
new file mode 100644
index 0000000..bc69cb7
--- /dev/null
+++ b/testdata/error_object.golden
@@ -0,0 +1,10 @@
+RUNTIME ERROR: {"blah": 42}
+-------------------------------------------------
+	testdata/error_object:1:1-21	$
+
+error { "blah": 42 }
+
+-------------------------------------------------
+	During evaluation	
+
+
diff --git a/testdata/error_object.jsonnet b/testdata/error_object.jsonnet
new file mode 100644
index 0000000..c6461fa
--- /dev/null
+++ b/testdata/error_object.jsonnet
@@ -0,0 +1 @@
+error { "blah": 42 }
\ No newline at end of file