feat(go): implement Compiler.Errors that returns the compilation er…

…rors.

capi/include/yara_x.h

@@ -319,8 +319,39 @@ enum YRX_RESULT yrx_compiler_define_global_float(struct YRX_COMPILER *compiler,
 //
 // In the address indicated by the `buf` pointer, the function will copy a
 // `YRX_BUFFER*` pointer. The `YRX_BUFFER` structure represents a buffer
-// that contains the JSON representation of the compilation errors. The
-// [`YRX_BUFFER`] must be destroyed with [`yrx_buffer_destroy`].
+// that contains the JSON representation of the compilation errors.
+//
+// The JSON consists on an array of objects, each object representing a
+// compilation error. The object has the following fields:
+//
+// * type: A string that describes the type of error.
+// * code: Error code (e.g: "E009").
+// * title: Error title (e.g: ""unknown identifier `foo`").
+// * labels: Array of labels.
+// * text: The full text of the error report, as shown by the command-line tool.
+//
+// Here is an example:
+//
+// ```json
+// [
+//     {
+//         "type": "UnknownIdentifier",
+//         "code": "E009",
+//         "title": "unknown identifier `foo`",
+//         "labels": [
+//             {
+//                 "level": "error",
+//                 "code_origin": null,
+//                 "span": {"start":25,"end":28},
+//                 "text": "this identifier has not been declared"
+//             }
+//         ],
+//         "text": "... <full report here> ..."
+//     }
+// ]
+// ```
+//
+// The [`YRX_BUFFER`] must be destroyed with [`yrx_buffer_destroy`].
 enum YRX_RESULT yrx_compiler_errors_json(struct YRX_COMPILER *compiler,
                                          struct YRX_BUFFER **buf);
 

capi/src/compiler.rs

@@ -242,8 +242,39 @@ pub unsafe extern "C" fn yrx_compiler_define_global_float(
 ///
 /// In the address indicated by the `buf` pointer, the function will copy a
 /// `YRX_BUFFER*` pointer. The `YRX_BUFFER` structure represents a buffer
-/// that contains the JSON representation of the compilation errors. The
-/// [`YRX_BUFFER`] must be destroyed with [`yrx_buffer_destroy`].
+/// that contains the JSON representation of the compilation errors.
+///
+/// The JSON consists on an array of objects, each object representing a
+/// compilation error. The object has the following fields:
+///
+/// * type: A string that describes the type of error.
+/// * code: Error code (e.g: "E009").
+/// * title: Error title (e.g: ""unknown identifier `foo`").
+/// * labels: Array of labels.
+/// * text: The full text of the error report, as shown by the command-line tool.
+///
+/// Here is an example:
+///
+/// ```json
+/// [
+///     {
+///         "type": "UnknownIdentifier",
+///         "code": "E009",
+///         "title": "unknown identifier `foo`",
+///         "labels": [
+///             {
+///                 "level": "error",
+///                 "code_origin": null,
+///                 "span": {"start":25,"end":28},
+///                 "text": "this identifier has not been declared"
+///             }
+///         ],
+///         "text": "... <full report here> ..."
+///     }
+/// ]
+/// ```
+///
+/// The [`YRX_BUFFER`] must be destroyed with [`yrx_buffer_destroy`].
 #[no_mangle]
 pub unsafe extern "C" fn yrx_compiler_errors_json(
     compiler: *mut YRX_COMPILER,

go/compiler.go

@@ -3,6 +3,7 @@ package yara_x
 // #include <yara_x.h>
 import "C"
 import (
+	"encoding/json"
 	"errors"
 	"fmt"
 	"runtime"
@@ -80,6 +81,41 @@ func ErrorOnSlowPattern(yes bool) CompileOption {
   	}
 }
 
+// CompileError represents each of the errors returned by [Compiler.Errors].
+type CompileError struct {
+	// Error code (e.g: "E001").
+	Code string
+	// Error title (e.g: "unknown identifier `foo`").
+	Title string
+	// Each of the labels in the error report.
+	Labels []Label
+	// The error's full report, as shown by the command-line tool.
+	Text string
+}
+
+// Label represents a label in a [CompileError].
+type Label struct {
+	// Label's level (e.g: "error", "warning", "info", "note", "help").
+	Level string
+	CodeOrigin string
+	// The code span covered by the label.
+	Span Span
+	// Text associated to the label.
+	Text string
+}
+
+// Span represents the starting and ending point of some piece of source
+// code.
+type Span struct {
+	Start int
+	End int
+}
+
+// Error returns the error's full report.
+func (c CompileError) Error() string {
+	return c.Text
+}
+
 // Compiler represent a YARA compiler.
 type Compiler struct {
 	cCompiler       *C.YRX_COMPILER
@@ -254,6 +290,29 @@ func (c *Compiler) DefineGlobal(ident string, value interface{}) error {
 	return nil
 }
 
+
+// Errors that occurred during the compilation, across multiple calls to
+// [Compiler.AddSource].
+func (c *Compiler) Errors() []CompileError {
+	var buf *C.YRX_BUFFER
+	if C.yrx_compiler_errors_json(c.cCompiler, &buf) != C.SUCCESS {
+		panic("yrx_compiler_errors_json failed")
+	}
+
+	defer C.yrx_buffer_destroy(buf)
+	runtime.KeepAlive(c)
+
+	jsonErrors := C.GoBytes(unsafe.Pointer(buf.data), C.int(buf.length))
+
+	var result []CompileError
+
+	if err := json.Unmarshal(jsonErrors, &result); err != nil {
+		panic(err)
+	}
+
+	return result
+}
+
 // Build creates a [Rules] object containing a compiled version of all the
 // YARA rules previously added to the compiler.
 //

go/compiler_test.go

@@ -107,10 +107,42 @@ func TestVariables(t *testing.T) {
 
 func TestError(t *testing.T) {
 	_, err := Compile("rule test { condition: foo }")
-	assert.EqualError(t, err, `error[E009]: unknown identifier `+"`foo`"+`
+	expected := `error[E009]: unknown identifier `+"`foo`"+`
  --> line:1:24
   |
 1 | rule test { condition: foo }
   |                        ^^^ this identifier has not been declared
-  |`)
+  |`
+	assert.EqualError(t, err, expected)
+}
+
+
+func TestErrors(t *testing.T) {
+	c, err := NewCompiler()
+	assert.NoError(t, err)
+
+	c.AddSource("rule test_1 { condition: true }")
+	assert.Equal(t, []CompileError{}, c.Errors())
+
+	c.AddSource("rule test_2 { condition: foo }")
+	assert.Equal(t, []CompileError{
+		{
+			Code: "E009",
+			Title: "unknown identifier `foo`",
+			Labels: []Label{
+				{
+					Level: "error",
+					CodeOrigin: "",
+					Span: Span { Start: 25, End: 28 },
+					Text: "this identifier has not been declared",
+				},
+			},
+			Text: `error[E009]: unknown identifier `+"`foo`"+`
+ --> line:1:26
+  |
+1 | rule test_2 { condition: foo }
+  |                          ^^^ this identifier has not been declared
+  |`,
+		},
+	}, c.Errors())
 }