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Merged
ianthomas23 merged 3 commits into from
Mar 11, 2026
Merged

Add --find-renames and --find-copies to the diff command #115

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dbe7920
add --find-renames and --find-copies to the diff command
SandrineP Feb 18, 2026
478545d
address review comments
SandrineP Mar 11, 2026
9f38625
address review comments
SandrineP Mar 11, 2026
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125 changes: 82 additions & 43 deletions src/subcommand/diff_subcommand.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,8 @@ diff_subcommand::diff_subcommand(const libgit2_object&, CLI::App& app)
{
auto* sub = app.add_subcommand("diff", "Show changes between commits, commit and working tree, etc");

sub->add_option("<files>", m_files, "tree-ish objects to compare");
sub->add_option("<files>", m_files, "tree-ish objects to compare")
->expected(0, 2);

sub->add_flag("--stat", m_stat_flag, "Generate a diffstat");
sub->add_flag("--shortstat", m_shortstat_flag, "Output only the last line of --stat");
Expand All @@ -33,15 +34,16 @@ diff_subcommand::diff_subcommand(const libgit2_object&, CLI::App& app)
sub->add_flag("--patience", m_patience_flag, "Generate diff using patience algorithm");
sub->add_flag("--minimal", m_minimal_flag, "Spend extra time to find smallest diff");

// TODO: add the following flags after the "move" subcommand has been implemented (needed for the tests)
// sub->add_option("-M,--find-renames", m_rename_threshold, "Detect renames")
// ->expected(0,1)
// ->each([this](const std::string&) { m_find_renames_flag = true; });
// sub->add_option("-C,--find-copies", m_copy_threshold, "Detect copies")
// ->expected(0,1)
// ->each([this](const std::string&) { m_find_copies_flag = true; });
// sub->add_flag("--find-copies-harder", m_find_copies_harder_flag, "Detect copies from unmodified files");
// sub->add_flag("-B,--break-rewrites", m_break_rewrites_flag, "Detect file rewrites");
sub->add_option("-M,--find-renames", m_rename_threshold, "Detect renames")
->expected(0,1)
->default_val(50)
->each([this](const std::string&) { m_find_renames_flag = true; });
sub->add_option("-C,--find-copies", m_copy_threshold, "Detect copies")
->expected(0,1)
->default_val(50)
->each([this](const std::string&) { m_find_copies_flag = true; });
sub->add_flag("--find-copies-harder", m_find_copies_harder_flag, "Detect copies from unmodified files");
sub->add_flag("-B,--break-rewrites", m_break_rewrites_flag, "Detect file rewrites");

sub->add_option("-U,--unified", m_context_lines, "Lines of context");
sub->add_option("--inter-hunk-context", m_interhunk_lines, "Context between hunks");
Expand Down Expand Up @@ -142,7 +144,6 @@ static int colour_printer([[maybe_unused]] const git_diff_delta* delta, [[maybe_
bool use_colour = *reinterpret_cast<bool*>(payload);

// Only print origin for context/addition/deletion lines
// For other line types, content already includes everything
bool print_origin = (line->origin == GIT_DIFF_LINE_CONTEXT ||
line->origin == GIT_DIFF_LINE_ADDITION ||
line->origin == GIT_DIFF_LINE_DELETION);
Expand Down Expand Up @@ -172,6 +173,39 @@ static int colour_printer([[maybe_unused]] const git_diff_delta* delta, [[maybe_
std::cout << termcolor::reset;
}

// Print copy/rename headers ONLY after the "diff --git" line
if (line->origin == GIT_DIFF_LINE_FILE_HDR)
{
if (delta->status == GIT_DELTA_COPIED)
{
if (use_colour)
{
std::cout << termcolor::bold;
}
std::cout << "similarity index " << delta->similarity << "%\n";
std::cout << "copy from " << delta->old_file.path << "\n";
std::cout << "copy to " << delta->new_file.path << "\n";
if (use_colour)
{
std::cout << termcolor::reset;
}
}
else if (delta->status == GIT_DELTA_RENAMED)
{
if (use_colour)
{
std::cout << termcolor::bold;
}
std::cout << "similarity index " << delta->similarity << "%\n";
std::cout << "rename from " << delta->old_file.path << "\n";
std::cout << "rename to " << delta->new_file.path << "\n";
if (use_colour)
{
std::cout << termcolor::reset;
}
}
}

return 0;
}

Expand All @@ -183,33 +217,30 @@ void diff_subcommand::print_diff(diff_wrapper& diff, bool use_colour)
return;
}

// TODO: add the following flags after the "move" subcommand has been implemented (needed for the tests)
// if (m_find_renames_flag || m_find_copies_flag || m_find_copies_harder_flag || m_break_rewrites_flag)
// {
// git_diff_find_options find_opts;
// git_diff_find_options_init(&find_opts, GIT_DIFF_FIND_OPTIONS_VERSION);

// if (m_find_renames_flag)
// {
// find_opts.flags |= GIT_DIFF_FIND_RENAMES;
// find_opts.rename_threshold = m_rename_threshold;
// }
// if (m_find_copies_flag)
// {
// find_opts.flags |= GIT_DIFF_FIND_COPIES;
// find_opts.copy_threshold = m_copy_threshold;
// }
// if (m_find_copies_harder_flag)
// {
// find_opts.flags |= GIT_DIFF_FIND_COPIES_FROM_UNMODIFIED;
// }
// if (m_break_rewrites_flag)
// {
// find_opts.flags |= GIT_DIFF_FIND_REWRITES;
// }

// diff.find_similar(&find_opts);
// }
if (m_find_renames_flag || m_find_copies_flag || m_find_copies_harder_flag || m_break_rewrites_flag)
{
git_diff_find_options find_opts = GIT_DIFF_FIND_OPTIONS_INIT;

if (m_find_renames_flag || m_find_copies_flag)
{
find_opts.flags |= GIT_DIFF_FIND_RENAMES;
find_opts.rename_threshold = m_rename_threshold;
}
if (m_find_copies_flag)
{
find_opts.flags |= GIT_DIFF_FIND_COPIES;
find_opts.copy_threshold = m_copy_threshold;
}
if (m_find_copies_harder_flag)
{
find_opts.flags |= GIT_DIFF_FIND_COPIES_FROM_UNMODIFIED;
}
if (m_break_rewrites_flag)
{
find_opts.flags |= GIT_DIFF_FIND_REWRITES;
}
diff.find_similar(&find_opts);
}

git_diff_format_t format = GIT_DIFF_FORMAT_PATCH;
if (m_name_only_flag)
Expand All @@ -228,7 +259,7 @@ void diff_subcommand::print_diff(diff_wrapper& diff, bool use_colour)
diff.print(format, colour_printer, &use_colour);
}

diff_wrapper compute_diff_no_index(std::vector<std::string> files, git_diff_options& diffopts) //std::pair<buf_wrapper, diff_wrapper>
diff_wrapper compute_diff_no_index(std::vector<std::string> files, git_diff_options& diffopts)
{
if (files.size() != 2)
{
Expand All @@ -242,11 +273,11 @@ diff_wrapper compute_diff_no_index(std::vector<std::string> files, git_diff_opti

if (file1_str.empty())
{
throw git_exception("Cannot read file: " + files[0], git2cpp_error_code::GENERIC_ERROR); //TODO: check error code with git
throw git_exception("Cannot read file: " + files[0], git2cpp_error_code::GENERIC_ERROR);
}
if (file2_str.empty())
{
throw git_exception("Cannot read file: " + files[1], git2cpp_error_code::GENERIC_ERROR); //TODO: check error code with git
throw git_exception("Cannot read file: " + files[1], git2cpp_error_code::GENERIC_ERROR);
}

auto patch = patch_wrapper::patch_from_files(files[0], file1_str, files[1], file2_str, &diffopts);
Expand Down Expand Up @@ -280,6 +311,11 @@ void diff_subcommand::run()
use_colour = true;
}

if (m_cached_flag && m_no_index_flag)
{
throw git_exception("--cached and --no-index are incompatible", git2cpp_error_code::BAD_ARGUMENT);
}

if (m_no_index_flag)
{
auto diff = compute_diff_no_index(m_files, diffopts);
Expand All @@ -302,11 +338,14 @@ void diff_subcommand::run()
if (m_untracked_flag) { diffopts.flags |= GIT_DIFF_INCLUDE_UNTRACKED; }
if (m_patience_flag) { diffopts.flags |= GIT_DIFF_PATIENCE; }
if (m_minimal_flag) { diffopts.flags |= GIT_DIFF_MINIMAL; }
if (m_find_copies_flag || m_find_copies_harder_flag || m_find_renames_flag)
{
diffopts.flags |= GIT_DIFF_INCLUDE_UNMODIFIED;
}

std::optional<tree_wrapper> tree1;
std::optional<tree_wrapper> tree2;

// TODO: throw error if m_files.size() > 2
if (m_files.size() >= 1)
{
tree1 = repo.treeish_to_tree(m_files[0]);
Expand All @@ -324,7 +363,7 @@ void diff_subcommand::run()
}
else if (m_cached_flag)
{
if (m_cached_flag || !tree1)
if (!tree1)
{
tree1 = repo.treeish_to_tree("HEAD");
}
Expand Down
20 changes: 10 additions & 10 deletions src/subcommand/diff_subcommand.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -38,16 +38,16 @@ class diff_subcommand
bool m_patience_flag = false;
bool m_minimal_flag = false;

// int m_rename_threshold = 50;
// bool m_find_renames_flag = false;
// int m_copy_threshold = 50;
// bool m_find_copies_flag = false;
// bool m_find_copies_harder_flag = false;
// bool m_break_rewrites_flag = false;

int m_context_lines = 3;
int m_interhunk_lines = 0;
int m_abbrev = 7;
uint16_t m_rename_threshold = 50;
bool m_find_renames_flag = false;
uint16_t m_copy_threshold = 50;
bool m_find_copies_flag = false;
bool m_find_copies_harder_flag = false;
bool m_break_rewrites_flag = false;

uint m_context_lines = 3;
uint m_interhunk_lines = 0;
uint m_abbrev = 7;

bool m_colour_flag = true;
bool m_no_colour_flag = false;
Expand Down
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