Add show-ref subcommand

CMakeLists.txt

@@ -78,6 +78,8 @@ set(GIT2CPP_SRC
     ${GIT2CPP_SOURCE_DIR}/subcommand/revparse_subcommand.hpp
     ${GIT2CPP_SOURCE_DIR}/subcommand/rm_subcommand.cpp
     ${GIT2CPP_SOURCE_DIR}/subcommand/rm_subcommand.hpp
+    ${GIT2CPP_SOURCE_DIR}/subcommand/showref_subcommand.cpp
+    ${GIT2CPP_SOURCE_DIR}/subcommand/showref_subcommand.hpp
     ${GIT2CPP_SOURCE_DIR}/subcommand/stash_subcommand.cpp
     ${GIT2CPP_SOURCE_DIR}/subcommand/stash_subcommand.hpp
     ${GIT2CPP_SOURCE_DIR}/subcommand/status_subcommand.cpp

src/main.cpp

@@ -23,6 +23,7 @@
 #include "subcommand/revlist_subcommand.hpp"
 #include "subcommand/revparse_subcommand.hpp"
 #include "subcommand/rm_subcommand.hpp"
+#include "subcommand/showref_subcommand.hpp"
 #include "subcommand/stash_subcommand.hpp"
 #include "subcommand/status_subcommand.hpp"
 #include "subcommand/tag_subcommand.hpp"
@@ -63,6 +64,7 @@ int main(int argc, char** argv)
         rm_subcommand rm(lg2_obj, app);
         stash_subcommand stash(lg2_obj, app);
         tag_subcommand tag(lg2_obj, app);
+        showref_subcommand showref(lg2_obj, app);
 
         app.require_subcommand(/* min */ 0, /* max */ 1);
 

src/subcommand/showref_subcommand.cpp

@@ -0,0 +1,31 @@
+#include "showref_subcommand.hpp"
+
+#include <git2.h>
+
+#include "../wrapper/repository_wrapper.hpp"
+
+showref_subcommand::showref_subcommand(const libgit2_object&, CLI::App& app)
+{
+    auto* sub = app.add_subcommand("show-ref", "List references in a local repository");
+
+    sub->callback(
+        [this]()
+        {
+            this->run();
+        }
+    );
+};
+
+void showref_subcommand::run()
+{
+    auto directory = get_current_git_path();
+    auto repo = repository_wrapper::open(directory);
+
+    auto repo_refs = repo.reference_list();
+
+    for (auto r : repo_refs)
+    {
+        git_oid oid = repo.ref_name_to_id(r);
+        std::cout << oid_to_hex(oid) << " " << r << std::endl;
+    }
+}

src/subcommand/showref_subcommand.hpp

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <CLI/CLI.hpp>
+
+#include "../utils/common.hpp"
+
+class showref_subcommand
+{
+public:
+
+    explicit showref_subcommand(const libgit2_object&, CLI::App& app);
+    void run();
+
+private:
+};

src/utils/common.cpp

@@ -142,3 +142,11 @@ std::string trim(const std::string& str)
     auto s = std::regex_replace(str, std::regex("^\\s+"), "");
     return std::regex_replace(s, std::regex("\\s+$"), "");
 }
+
+std::string oid_to_hex(const git_oid& oid)
+{
+    char oid_str[GIT_OID_SHA1_HEXSIZE + 1];
+    git_oid_fmt(oid_str, &oid);
+    oid_str[GIT_OID_SHA1_HEXSIZE] = '\0';
+    return std::string(oid_str);
+}

src/utils/common.hpp

@@ -79,3 +79,5 @@ std::vector<std::string> split_input_at_newlines(std::string_view str);
 
 // Remove whitespace from start and end of a string.
 std::string trim(const std::string& str);
+
+std::string oid_to_hex(const git_oid& oid);

src/wrapper/repository_wrapper.cpp

@@ -134,6 +134,26 @@ std::optional<reference_wrapper> repository_wrapper::find_reference_dwim(std::st
     return rc == 0 ? std::make_optional(reference_wrapper(ref)) : std::nullopt;
 }
 
+std::vector<std::string> repository_wrapper::reference_list() const
+{
+    git_strarray refs = {0};
+    throw_if_error(git_reference_list(&refs, *this));
+    std::vector<std::string> result;
+    for (size_t i = 0; i < refs.count; ++i)
+    {
+        result.push_back(refs.strings[i]);
+    }
+    git_strarray_free(&refs);
+    return result;
+}
+
+const git_oid repository_wrapper::ref_name_to_id(std::string ref_name) const
+{
+    git_oid ref_id;
+    throw_if_error(git_reference_name_to_id(&ref_id, *this, ref_name.c_str()));
+    return ref_id;
+}
+
 // Index
 
 index_wrapper repository_wrapper::make_index()

src/wrapper/repository_wrapper.hpp

@@ -6,7 +6,6 @@
 
 #include <git2.h>
 
-#include "../utils/common.hpp"
 #include "../utils/git_exception.hpp"
 #include "../wrapper/annotated_commit_wrapper.hpp"
 #include "../wrapper/branch_wrapper.hpp"
@@ -63,6 +62,8 @@ class repository_wrapper : public wrapper_base<git_repository>
     // References
     reference_wrapper find_reference(std::string_view ref_name) const;
     std::optional<reference_wrapper> find_reference_dwim(std::string_view ref_name) const;
+    std::vector<std::string> reference_list() const;
+    const git_oid ref_name_to_id(std::string ref_name) const;
 
     // Index
     index_wrapper make_index();

test/test_fetch.py

@@ -1,6 +1,7 @@
-import pytest
 import subprocess
 
+import pytest
+
 
 @pytest.mark.parametrize("protocol", ["http", "https"])
 def test_fetch_private_repo(git2cpp_path, tmp_path, run_in_tmp_path, private_test_repo, protocol):

test/test_showref.py

@@ -0,0 +1,48 @@
+import re
+import subprocess
+
+
+def test_showref_list(repo_init_with_commit, git2cpp_path, tmp_path):
+    """`show-ref` lists the repository references (heads present after init+commit)."""
+    cmd = [git2cpp_path, "show-ref"]
+    p = subprocess.run(cmd, capture_output=True, cwd=tmp_path, text=True)
+    assert p.returncode == 0
+    # repo_init_with_commit in conftest creates the branch "main"
+    assert "refs/heads/main" in p.stdout
+
+
+def test_showref_includes_tag(repo_init_with_commit, git2cpp_path, tmp_path):
+    """A created tag appears in show-ref output as refs/tags/<name>."""
+    # create a lightweight tag using the CLI under test
+    subprocess.run([git2cpp_path, "tag", "v1.0"], cwd=tmp_path, check=True)
+
+    p = subprocess.run([git2cpp_path, "show-ref"], capture_output=True, cwd=tmp_path, text=True)
+    assert p.returncode == 0
+    assert "refs/tags/v1.0" in p.stdout
+
+
+def test_showref_line_format(repo_init_with_commit, git2cpp_path, tmp_path):
+    """Each line of show-ref is: <40-hex-oid> <refname>."""
+    p = subprocess.run([git2cpp_path, "show-ref"], capture_output=True, cwd=tmp_path, text=True)
+    assert p.returncode == 0
+    print(p.stdout)
+
+    hex_re = re.compile(r"^[0-9a-f]{40}$")
+    for line in p.stdout.splitlines():
+        line = line.strip()
+        if not line:
+            continue
+        parts = line.split()
+        # Expect at least two tokens: oid and refname
+        assert len(parts) >= 2
+        oid, refname = parts[0], parts[1]
+        assert hex_re.match(oid), f"OID not a 40-char hex: {oid!r}"
+        assert refname.startswith("refs/"), f"Refname does not start with refs/: {refname!r}"
+
+
+def test_showref_nogit(git2cpp_path, tmp_path):
+    """Running show-ref outside a repository returns an error and non-zero exit."""
+    cmd = [git2cpp_path, "show-ref"]
+    p = subprocess.run(cmd, capture_output=True, cwd=tmp_path, text=True)
+    assert p.returncode != 0
+    assert "error: could not find repository at" in p.stderr