From 23df5748f6d05b5b2255dd3859342734e5c71bcf Mon Sep 17 00:00:00 2001
From: Shannon Booth <shannon.ml.booth@gmail.com>
Date: Sat, 24 Jun 2023 12:44:22 +1200
Subject: [PATCH] LibDiff: Make Diff::parse_hunks fallible

Currently the only error that can happen is an OOM. However, in the
future there may be other errors that this function may throw, such as
detecting an invalid patch.
---
 Userland/DevTools/HackStudio/EditorWrapper.cpp  |  2 +-
 Userland/DevTools/HackStudio/Git/DiffViewer.cpp |  4 ++--
 Userland/Libraries/LibDiff/Hunks.cpp            | 11 ++++++-----
 Userland/Libraries/LibDiff/Hunks.h              |  2 +-
 4 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/Userland/DevTools/HackStudio/EditorWrapper.cpp b/Userland/DevTools/HackStudio/EditorWrapper.cpp
index ea104594db..9d377013ff 100644
--- a/Userland/DevTools/HackStudio/EditorWrapper.cpp
+++ b/Userland/DevTools/HackStudio/EditorWrapper.cpp
@@ -88,7 +88,7 @@ void EditorWrapper::save()
 void EditorWrapper::update_diff()
 {
     if (m_git_repo) {
-        m_hunks = Diff::parse_hunks(m_git_repo->unstaged_diff(filename()).value());
+        m_hunks = Diff::parse_hunks(m_git_repo->unstaged_diff(filename()).value()).release_value_but_fixme_should_propagate_errors();
         editor().update_git_diff_indicators().release_value_but_fixme_should_propagate_errors();
     }
 }
diff --git a/Userland/DevTools/HackStudio/Git/DiffViewer.cpp b/Userland/DevTools/HackStudio/Git/DiffViewer.cpp
index 2eb501b6cf..078289e0d5 100644
--- a/Userland/DevTools/HackStudio/Git/DiffViewer.cpp
+++ b/Userland/DevTools/HackStudio/Git/DiffViewer.cpp
@@ -134,7 +134,7 @@ Gfx::IntRect DiffViewer::separator_rect() const
 void DiffViewer::set_content(DeprecatedString const& original, DeprecatedString const& diff)
 {
     m_original_lines = split_to_lines(original);
-    m_hunks = Diff::parse_hunks(diff);
+    m_hunks = Diff::parse_hunks(diff).release_value_but_fixme_should_propagate_errors();
 
     if constexpr (DIFF_DEBUG) {
         for (size_t i = 0; i < m_original_lines.size(); ++i)
@@ -149,7 +149,7 @@ DiffViewer::DiffViewer()
 
 DiffViewer::DiffViewer(DeprecatedString const& original, DeprecatedString const& diff)
     : m_original_lines(split_to_lines(original))
-    , m_hunks(Diff::parse_hunks(diff))
+    , m_hunks(Diff::parse_hunks(diff).release_value_but_fixme_should_propagate_errors())
 {
     setup_properties();
 }
diff --git a/Userland/Libraries/LibDiff/Hunks.cpp b/Userland/Libraries/LibDiff/Hunks.cpp
index 1482103841..ae029d61c5 100644
--- a/Userland/Libraries/LibDiff/Hunks.cpp
+++ b/Userland/Libraries/LibDiff/Hunks.cpp
@@ -8,11 +8,12 @@
 #include <AK/Debug.h>
 
 namespace Diff {
-Vector<Hunk> parse_hunks(DeprecatedString const& diff)
+
+ErrorOr<Vector<Hunk>> parse_hunks(DeprecatedString const& diff)
 {
     Vector<DeprecatedString> diff_lines = diff.split('\n');
     if (diff_lines.is_empty())
-        return {};
+        return Vector<Hunk> {};
 
     Vector<Hunk> hunks;
 
@@ -40,12 +41,12 @@ Vector<Hunk> parse_hunks(DeprecatedString const& diff)
         hunk.target_start_line = current_location.target_start_line;
 
         while (line_index < diff_lines.size() && diff_lines[line_index][0] == '-') {
-            hunk.removed_lines.append(diff_lines[line_index].substring(1, diff_lines[line_index].length() - 1));
+            TRY(hunk.removed_lines.try_append(diff_lines[line_index].substring(1, diff_lines[line_index].length() - 1)));
             current_location.apply_offset(1, HunkLocation::LocationType::Original);
             ++line_index;
         }
         while (line_index < diff_lines.size() && diff_lines[line_index][0] == '+') {
-            hunk.added_lines.append(diff_lines[line_index].substring(1, diff_lines[line_index].length() - 1));
+            TRY(hunk.added_lines.try_append(diff_lines[line_index].substring(1, diff_lines[line_index].length() - 1)));
             current_location.apply_offset(1, HunkLocation::LocationType::Target);
             ++line_index;
         }
@@ -54,7 +55,7 @@ Vector<Hunk> parse_hunks(DeprecatedString const& diff)
             current_location.apply_offset(1, HunkLocation::LocationType::Both);
             ++line_index;
         }
-        hunks.append(hunk);
+        TRY(hunks.try_append(hunk));
     }
 
     if constexpr (HUNKS_DEBUG) {
diff --git a/Userland/Libraries/LibDiff/Hunks.h b/Userland/Libraries/LibDiff/Hunks.h
index dd140feb8e..256458cd97 100644
--- a/Userland/Libraries/LibDiff/Hunks.h
+++ b/Userland/Libraries/LibDiff/Hunks.h
@@ -32,6 +32,6 @@ struct Hunk {
     Vector<DeprecatedString> added_lines;
 };
 
-Vector<Hunk> parse_hunks(DeprecatedString const& diff);
+ErrorOr<Vector<Hunk>> parse_hunks(DeprecatedString const& diff);
 HunkLocation parse_hunk_location(StringView location_line);
 };