From a371b10180a71361fa4588448d95460951d48e78 Mon Sep 17 00:00:00 2001
From: Fernando Araoz <fernando@araozu.dev>
Date: Sat, 28 Dec 2024 07:23:38 -0500
Subject: [PATCH] fix: memory leaks on error handling

---
 src/01_lexic/number.zig | 5 +++++
 src/01_lexic/root.zig   | 1 +
 src/01_lexic/token.zig  | 1 +
 src/errors/root.zig     | 9 +++++++++
 4 files changed, 16 insertions(+)

diff --git a/src/01_lexic/number.zig b/src/01_lexic/number.zig
index 6f988e0..c52d5a6 100644
--- a/src/01_lexic/number.zig
+++ b/src/01_lexic/number.zig
@@ -67,6 +67,7 @@ fn prefixed(
     if (end_position >= cap or !validator(input[end_position])) {
         // populate error information
         try err.init("Incomplete number", start, end_position, alloc);
+        try err.add_label("Expected a valid digit after the '" ++ [_]u8{prefix} ++ "'", start, end_position);
 
         // throw error
         return LexError.Incomplete;
@@ -303,6 +304,7 @@ test "shouldnt parse incomplete hex number" {
     defer std.testing.allocator.destroy(errdata);
     const result = lex(input, input.len, 0, errdata, std.testing.allocator) catch |err| {
         try std.testing.expect(err == token.LexError.Incomplete);
+        defer errdata.deinit();
         return;
     };
 
@@ -322,6 +324,7 @@ test "shouldnt parse incomplete hex number 2" {
     defer std.testing.allocator.destroy(errdata);
     const result = lex(input, input.len, 0, errdata, std.testing.allocator) catch |err| {
         try std.testing.expect(err == token.LexError.Incomplete);
+        defer errdata.deinit();
         return;
     };
 
@@ -365,6 +368,7 @@ test "shouldnt parse incomplete octal number" {
     defer std.testing.allocator.destroy(errdata);
     const result = lex(input, input.len, 0, errdata, std.testing.allocator) catch |err| {
         try std.testing.expect(err == token.LexError.Incomplete);
+        defer errdata.deinit();
         return;
     };
 
@@ -396,6 +400,7 @@ test "shouldnt parse incomplete binary number" {
     defer std.testing.allocator.destroy(errdata);
     const result = lex(input, input.len, 0, errdata, std.testing.allocator) catch |err| {
         try std.testing.expect(err == token.LexError.Incomplete);
+        defer errdata.deinit();
         return;
     };
 
diff --git a/src/01_lexic/root.zig b/src/01_lexic/root.zig
index 28d282b..8018b7a 100644
--- a/src/01_lexic/root.zig
+++ b/src/01_lexic/root.zig
@@ -214,6 +214,7 @@ test "should handle recoverable errors" {
     const input = "322 0b 644";
     var error_list = std.ArrayList(errors.ErrorData).init(std.testing.allocator);
     defer error_list.deinit();
+    defer for (error_list.items) |*err| err.deinit();
     const arrl = try tokenize(input, std.testing.allocator, &error_list);
     defer arrl.deinit();
 
diff --git a/src/01_lexic/token.zig b/src/01_lexic/token.zig
index bf1aae1..73d0cca 100644
--- a/src/01_lexic/token.zig
+++ b/src/01_lexic/token.zig
@@ -41,6 +41,7 @@ pub const LexError = error{
     IncompleteScientificNumber,
     IncompleteString,
     CRLF,
+    OutOfMemory,
 };
 
 /// Contains the lexed token and the next position
diff --git a/src/errors/root.zig b/src/errors/root.zig
index 0e6907e..08b2252 100644
--- a/src/errors/root.zig
+++ b/src/errors/root.zig
@@ -10,6 +10,7 @@ pub const ErrorLabel = struct {
 /// and pretty prints them.
 pub const ErrorData = struct {
     reason: []const u8,
+    help: ?[]const u8,
     start_position: usize,
     end_position: usize,
     labels: std.ArrayList(ErrorLabel),
@@ -27,6 +28,7 @@ pub const ErrorData = struct {
             .start_position = start_position,
             .end_position = end_position,
             .labels = std.ArrayList(ErrorLabel).init(alloc),
+            .help = null,
             .alloc = alloc,
         };
     }
@@ -39,6 +41,11 @@ pub const ErrorData = struct {
         });
     }
 
+    /// Sets the help message of this error.
+    pub fn set_help(self: *@This(), help: []const u8) void {
+        self.help = help;
+    }
+
     /// Generates an error string. `alloc` is used to create the string,
     /// the caller should call `free` on the returning slice.
     pub fn get_error_str(self: *@This(), source_code: []const u8, filename: []const u8, alloc: std.mem.Allocator) ![]u8 {
@@ -238,6 +245,7 @@ test "should gen error message" {
     const source = "print(ehh)";
     var err = ErrorData{
         .reason = "Invalid identifier",
+        .help = null,
         .start_position = 6,
         .end_position = 9,
         .labels = std.ArrayList(ErrorLabel).init(std.testing.allocator),
@@ -256,6 +264,7 @@ test "should gen error message with label (1)" {
     const source = "print(ehh)";
     var err = ErrorData{
         .reason = "Invalid identifier",
+        .help = null,
         .start_position = 6,
         .end_position = 9,
         .labels = std.ArrayList(ErrorLabel).init(std.testing.allocator),