Refactor git_repository_open with new options

Add a new command `git_repository_open_ext` with extended options
that control how searching for a repository will be done.  The
existing `git_repository_open` and `git_repository_discover` are
reimplemented on top of it.  We may want to change the default
behavior of `git_repository_open` but this commit does not do that.

Improve support for "gitdir" files where the work dir is separate
from the repo and support for the "separate-git-dir" config.  Also,
add support for opening repos created with `git-new-workdir` script
(although I have only confirmed that they can be opened, not that
all functions work correctly).

There are also a few minor changes that came up:

- Fix `git_path_prettify` to allow in-place prettifying.

- Fix `git_path_root` to support backslashes on Win32.  This fix
  should help many repo open/discover scenarios - it is the one
  function called when opening before prettifying the path.

- Tweak `git_config_get_string` to set the "out" pointer to NULL
  if the config value is not found.  Allows some other cleanup.

- Fix a couple places that should have been calling
  `git_repository_config__weakptr` and were not.

- Fix `cl_git_sandbox_init` clar helper to support bare repos.

include/git2/repository.h

@@ -70,6 +70,20 @@ GIT_EXTERN(int) git_repository_discover(
 		int across_fs,
 		const char *ceiling_dirs);
 
+enum {
+	GIT_REPOSITORY_OPEN_NO_SEARCH = (1 << 0),
+	GIT_REPOSITORY_OPEN_CROSS_FS  = (1 << 1),
+};
+
+/**
+ * Find and open a repository with extended controls.
+ */
+GIT_EXTERN(int) git_repository_open_ext(
+	git_repository **repo,
+	const char *start_path,
+	uint32_t flags,
+	const char *ceiling_dirs);
+
 /**
  * Free a previously allocated repository
  *

src/attr.c

@@ -347,6 +347,7 @@ static int collect_attr_files(
 
 int git_attr_cache__init(git_repository *repo)
 {
+	int ret;
 	git_attr_cache *cache = git_repository_attr_cache(repo);
 	git_config *cfg;
 
@@ -354,17 +355,18 @@ int git_attr_cache__init(git_repository *repo)
 		return 0;
 
 	/* cache config settings for attributes and ignores */
-	if (git_repository_config(&cfg, repo) < 0)
+	if (git_repository_config__weakptr(&cfg, repo) < 0)
 		return -1;
-	if (git_config_get_string(cfg, GIT_ATTR_CONFIG, &cache->cfg_attr_file)) {
-		giterr_clear();
-		cache->cfg_attr_file = NULL;
-	}
-	if (git_config_get_string(cfg, GIT_IGNORE_CONFIG, &cache->cfg_excl_file)) {
+
+	ret = git_config_get_string(cfg, GIT_ATTR_CONFIG, &cache->cfg_attr_file);
+	if (ret < 0 && ret != GIT_ENOTFOUND)
+		return ret;
+
+	ret = git_config_get_string(cfg, GIT_IGNORE_CONFIG, &cache->cfg_excl_file);
+	if (ret < 0 && ret != GIT_ENOTFOUND)
+		return ret;
+
 	giterr_clear();
-		cache->cfg_excl_file = NULL;
-	}
-	git_config_free(cfg);
 
 	/* allocate hashtable for attribute and ignore file contents */
 	if (cache->files == NULL) {

src/config.c

@@ -327,11 +327,11 @@ int git_config_lookup_map_value(
 int git_config_get_mapped(git_config *cfg, const char *name, git_cvar_map *maps, size_t map_n, int *out)
 {
 	const char *value;
-	int error;
+	int ret;
 
-	error = git_config_get_string(cfg, name, &value);
-	if (error < 0)
-		return error;
+	ret = git_config_get_string(cfg, name, &value);
+	if (ret < 0)
+		return ret;
 
 	if (!git_config_lookup_map_value(maps, map_n, value, out))
 		return 0;
@@ -399,25 +399,16 @@ int git_config_get_bool(git_config *cfg, const char *name, int *out)
 int git_config_get_string(git_config *cfg, const char *name, const char **out)
 {
 	file_internal *internal;
-	git_config_file *file;
-	int ret = GIT_ENOTFOUND;
 	unsigned int i;
 
 	assert(cfg->files.length);
 
-	for (i = 0; i < cfg->files.length; ++i) {
-		internal = git_vector_get(&cfg->files, i);
-		file = internal->file;
-
-		ret = file->get(file, name, out);
-		if (ret == 0)
-			return 0;
-
-		/* File backend doesn't set error message on variable
-		 * not found */
-		if (ret == GIT_ENOTFOUND)
-			continue;
+	*out = NULL;
 
+	git_vector_foreach(&cfg->files, i, internal) {
+		git_config_file *file = internal->file;
+		int ret = file->get(file, name, out);
+		if (ret != GIT_ENOTFOUND)
 			return ret;
 	}
 

src/diff.c

@@ -253,7 +253,7 @@ static git_diff_list *git_diff_list_alloc(
 	diff->repo = repo;
 
 	/* load config values that affect diff behavior */
-	if (git_repository_config(&cfg, repo) < 0)
+	if (git_repository_config__weakptr(&cfg, repo) < 0)
 		goto fail;
 	if (config_bool(cfg, "core.symlinks", 1))
 		diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_HAS_SYMLINKS;
@@ -264,7 +264,6 @@ static git_diff_list *git_diff_list_alloc(
 	if (config_bool(cfg, "core.trustctime", 1))
 		diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_TRUST_CTIME;
 	/* Don't set GIT_DIFFCAPS_USE_DEV - compile time option in core git */
-	git_config_free(cfg);
 
 	if (opts == NULL)
 		return diff;

src/errors.c

@@ -92,8 +92,12 @@ const char *git_lasterror(void)
 {
 	char *last_error = GIT_GLOBAL->error.last;
 
-	if (!last_error[0])
+	if (!last_error[0]) {
+		const git_error *err = git_error_last();
+		if (err != NULL)
+			return err->message;
 		return NULL;
+	}
 
 	return last_error;
 }

src/path.c

@@ -172,20 +172,22 @@ int git_path_root(const char *path)
 	if (isalpha(path[0]) && (path[1] == ':'))
 		offset += 2;
 
-	/* Are we dealing with a network path? */
-	else if (path[0] == '/' && path[1] == '/') {
+	/* Are we dealing with a windows network path? */
+	else if ((path[0] == '/' && path[1] == '/') ||
+		(path[0] == '\\' && path[1] == '\\'))
+	{
 		offset += 2;
 
 		/* Skip the computer name segment */
-		while (*(path + offset) && *(path + offset) != '/')
+		while (path[offset] && path[offset] != '/' && path[offset] != '\\')
 			offset++;
 	}
 #endif
 
-	if (*(path + offset) == '/')
+	if (path[offset] == '/' || path[offset] == '\\')
 		return offset;
 
-	return -1;	/* Not a real error. Rather a signal than the path is not rooted */
+	return -1;	/* Not a real error - signals that path is not rooted */
 }
 
 int git_path_prettify(git_buf *path_out, const char *path, const char *base)
@@ -193,26 +195,21 @@ int git_path_prettify(git_buf *path_out, const char *path, const char *base)
 	char buf[GIT_PATH_MAX];
 
 	assert(path && path_out);
-	git_buf_clear(path_out);
 
 	/* construct path if needed */
 	if (base != NULL && git_path_root(path) < 0) {
 		if (git_buf_joinpath(path_out, base, path) < 0)
 			return -1;
-
 		path = path_out->ptr;
 	}
 
 	if (p_realpath(path, buf) == NULL) {
-		giterr_set(GITERR_OS, "Failed to resolve path '%s': %s",
-			path, strerror(errno));
+		giterr_set(GITERR_OS, "Failed to resolve path '%s'", path);
+		git_buf_clear(path_out);
 		return (errno == ENOENT) ? GIT_ENOTFOUND : -1;
 	}
 
-	if (git_buf_sets(path_out, buf) < 0)
-		return -1;
-
-	return 0;
+	return git_buf_sets(path_out, buf);
 }
 
 int git_path_prettify_dir(git_buf *path_out, const char *path, const char *base)

tests-clar/clar_helpers.c

@@ -28,9 +28,9 @@ void cl_git_mkfile(const char *filename, const char *content)
 	cl_must_pass(p_close(fd));
 }
 
-void cl_git_append2file(const char *filename, const char *new_content)
+void cl_git_write2file(const char *filename, const char *new_content, int flags)
 {
-	int fd = p_open(filename, O_WRONLY | O_APPEND | O_CREAT);
+	int fd = p_open(filename, flags);
 	cl_assert(fd != 0);
 	if (!new_content)
 		new_content = "\n";
@@ -39,6 +39,16 @@ void cl_git_append2file(const char *filename, const char *new_content)
 	cl_must_pass(p_chmod(filename, 0644));
 }
 
+void cl_git_append2file(const char *filename, const char *new_content)
+{
+	cl_git_write2file(filename, new_content, O_WRONLY | O_APPEND | O_CREAT);
+}
+
+void cl_git_rewritefile(const char *filename, const char *new_content)
+{
+	cl_git_write2file(filename, new_content, O_WRONLY | O_CREAT | O_TRUNC);
+}
+
 static const char *_cl_sandbox = NULL;
 static git_repository *_cl_repo = NULL;
 
@@ -52,10 +62,11 @@ git_repository *cl_git_sandbox_init(const char *sandbox)
 
 	p_chdir(sandbox);
 
-	/* Rename `sandbox/.gitted` to `sandbox/.git` which must be done since
-	 * we cannot store a folder named `.git` inside the fixtures folder of
-	 * our libgit2 repo.
+	/* If this is not a bare repo, then rename `sandbox/.gitted` to
+	 * `sandbox/.git` which must be done since we cannot store a folder
+	 * named `.git` inside the fixtures folder of our libgit2 repo.
 	 */
+	if (p_access(".gitted", F_OK) == 0)
 		cl_git_pass(p_rename(".gitted", ".git"));
 
 	/* If we have `gitattributes`, rename to `.gitattributes`.  This may

tests-clar/clar_libgit2.h

@@ -57,6 +57,8 @@ GIT_INLINE(void) cl_assert_strequal_internal(
 /* Write the contents of a buffer to disk */
 void cl_git_mkfile(const char *filename, const char *content);
 void cl_git_append2file(const char *filename, const char *new_content);
+void cl_git_rewritefile(const char *filename, const char *new_content);
+void cl_git_write2file(const char *filename, const char *new_content, int mode);
 
 /* Git sandbox setup helpers */
 

tests-clar/repo/open.c

 #include "clar_libgit2.h"
-#include "posix.h"
-
-static git_repository *repo;
+#include "fileops.h"
 
 void test_repo_open__cleanup(void)
 {
-	git_repository_free(repo);
+	cl_git_sandbox_cleanup();
+
+	if (git_path_isdir("alternate"))
+		git_futils_rmdir_r("alternate", 1);
 }
 
 void test_repo_open__bare_empty_repo(void)
 {
-	cl_git_pass(git_repository_open(&repo, cl_fixture("empty_bare.git")));
+	git_repository *repo = cl_git_sandbox_init("empty_bare.git");
 
 	cl_assert(git_repository_path(repo) != NULL);
 	cl_assert(git__suffixcmp(git_repository_path(repo), "/") == 0);
-
 	cl_assert(git_repository_workdir(repo) == NULL);
 }
 
 void test_repo_open__standard_empty_repo_through_gitdir(void)
 {
+	git_repository *repo;
+
 	cl_git_pass(git_repository_open(&repo, cl_fixture("empty_standard_repo/.gitted")));
 
 	cl_assert(git_repository_path(repo) != NULL);
@@ -27,20 +29,246 @@ void test_repo_open__standard_empty_repo_through_gitdir(void)
 
 	cl_assert(git_repository_workdir(repo) != NULL);
 	cl_assert(git__suffixcmp(git_repository_workdir(repo), "/") == 0);
+
+	git_repository_free(repo);
 }
 
 void test_repo_open__standard_empty_repo_through_workdir(void)
 {
-	cl_fixture_sandbox("empty_standard_repo");
-	cl_git_pass(p_rename("empty_standard_repo/.gitted", "empty_standard_repo/.git"));
-
-	cl_git_pass(git_repository_open(&repo, "empty_standard_repo"));
+	git_repository *repo = cl_git_sandbox_init("empty_standard_repo");
 
 	cl_assert(git_repository_path(repo) != NULL);
 	cl_assert(git__suffixcmp(git_repository_path(repo), "/") == 0);
 
 	cl_assert(git_repository_workdir(repo) != NULL);
 	cl_assert(git__suffixcmp(git_repository_workdir(repo), "/") == 0);
+}
+
+
+void test_repo_open__open_with_discover(void)
+{
+	static const char *variants[] = {
+		"attr", "attr/", "attr/.git", "attr/.git/",
+		"attr/sub", "attr/sub/", "attr/sub/sub", "attr/sub/sub/",
+		NULL
+	};
+	git_repository *repo;
+	const char **scan;
+
+	cl_fixture_sandbox("attr");
+	cl_git_pass(p_rename("attr/.gitted", "attr/.git"));
+
+	for (scan = variants; *scan != NULL; scan++) {
+		cl_git_pass(git_repository_open_ext(&repo, *scan, 0, NULL));
+		cl_assert(git__suffixcmp(git_repository_path(repo), "attr/.git/") == 0);
+		cl_assert(git__suffixcmp(git_repository_workdir(repo), "attr/") == 0);
+		git_repository_free(repo);
+	}
+
+	cl_fixture_cleanup("attr");
+}
+
+void test_repo_open__gitlinked(void)
+{
+	/* need to have both repo dir and workdir set up correctly */
+	git_repository *repo = cl_git_sandbox_init("empty_standard_repo");
+	git_repository *repo2;
+
+	cl_must_pass(p_mkdir("alternate", 0777));
+	cl_git_mkfile("alternate/.git", "gitdir: ../empty_standard_repo/.git");
+
+	cl_git_pass(git_repository_open(&repo2, "alternate"));
+
+	cl_assert(git_repository_path(repo2) != NULL);
+	cl_assert_(git__suffixcmp(git_repository_path(repo2), "empty_standard_repo/.git/") == 0, git_repository_path(repo2));
+	cl_assert_equal_s(git_repository_path(repo), git_repository_path(repo2));
+
+	cl_assert(git_repository_workdir(repo2) != NULL);
+	cl_assert_(git__suffixcmp(git_repository_workdir(repo2), "alternate/") == 0, git_repository_workdir(repo2));
+
+	git_repository_free(repo2);
+}
+
+void test_repo_open__from_git_new_workdir(void)
+{
+	/* The git-new-workdir script that ships with git sets up a bunch of
+	 * symlinks to create a second workdir that shares the object db with
+	 * another checkout.  Libgit2 can open a repo that has been configured
+	 * this way.
+	 */
+	cl_git_sandbox_init("empty_standard_repo");
+
+#ifndef GIT_WIN32
+	git_repository *repo2;
+	git_buf link_tgt = GIT_BUF_INIT, link = GIT_BUF_INIT, body = GIT_BUF_INIT;
+	const char **scan;
+	int link_fd;
+	static const char *links[] = {
+		"config", "refs", "logs/refs", "objects", "info", "hooks",
+		"packed-refs", "remotes", "rr-cache", "svn", NULL
+	};
+	static const char *copies[] = {
+		"HEAD", NULL
+	};
+
+	cl_git_pass(p_mkdir("alternate", 0777));
+	cl_git_pass(p_mkdir("alternate/.git", 0777));
+
+	for (scan = links; *scan != NULL; scan++) {
+		git_buf_joinpath(&link_tgt, "empty_standard_repo/.git", *scan);
+		if (git_path_exists(link_tgt.ptr)) {
+			git_buf_joinpath(&link_tgt, "../../empty_standard_repo/.git", *scan);
+			git_buf_joinpath(&link, "alternate/.git", *scan);
+			if (strchr(*scan, '/'))
+				git_futils_mkpath2file(link.ptr, 0777);
+			cl_assert_(symlink(link_tgt.ptr, link.ptr) == 0, strerror(errno));
+		}
+	}
+	for (scan = copies; *scan != NULL; scan++) {
+		git_buf_joinpath(&link_tgt, "empty_standard_repo/.git", *scan);
+		if (git_path_exists(link_tgt.ptr)) {
+			git_buf_joinpath(&link, "alternate/.git", *scan);
+			cl_git_pass(git_futils_readbuffer(&body, link_tgt.ptr));
+
+			cl_assert((link_fd = git_futils_creat_withpath(link.ptr, 0777, 0666)) >= 0);
+			cl_must_pass(p_write(link_fd, body.ptr, body.size));
+			p_close(link_fd);
+		}
+	}
+
+	git_buf_free(&link_tgt);
+	git_buf_free(&link);
+	git_buf_free(&body);
+
+
+	cl_git_pass(git_repository_open(&repo2, "alternate"));
+
+	cl_assert(git_repository_path(repo2) != NULL);
+	cl_assert_(git__suffixcmp(git_repository_path(repo2), "alternate/.git/") == 0, git_repository_path(repo2));
+
+	cl_assert(git_repository_workdir(repo2) != NULL);
+	cl_assert_(git__suffixcmp(git_repository_workdir(repo2), "alternate/") == 0, git_repository_workdir(repo2));
+
+	git_repository_free(repo2);
+#endif
+}
+
+void test_repo_open__failures(void)
+{
+	git_repository *base, *repo;
+	git_buf ceiling = GIT_BUF_INIT;
+
+	base = cl_git_sandbox_init("attr");
+	cl_git_pass(git_buf_sets(&ceiling, git_repository_workdir(base)));
+
+	/* fail with no searching */
+	cl_git_fail(git_repository_open(&repo, "attr/sub"));
+	cl_git_fail(git_repository_open_ext(
+		&repo, "attr/sub", GIT_REPOSITORY_OPEN_NO_SEARCH, NULL));
+
+	/* fail with ceiling too low */
+	cl_git_pass(git_buf_joinpath(&ceiling, ceiling.ptr, "sub"));
+	cl_git_fail(git_repository_open_ext(&repo, "attr/sub", 0, ceiling.ptr));
+
+	/* fail with no repo */
+	cl_git_pass(p_mkdir("alternate", 0777));
+	cl_git_pass(p_mkdir("alternate/.git", 0777));
+	cl_git_fail(git_repository_open_ext(&repo, "alternate", 0, NULL));
+	cl_git_fail(git_repository_open_ext(&repo, "alternate/.git", 0, NULL));
+
+	git_buf_free(&ceiling);
+}
+
+void test_repo_open__bad_gitlinks(void)
+{
+	git_repository *repo;
+	static const char *bad_links[] = {
+		"garbage\n", "gitdir", "gitdir:\n", "gitdir: foobar",
+		"gitdir: ../invalid", "gitdir: ../invalid2",
+		"gitdir: ../attr/.git with extra stuff",
+		NULL
+	};
+	const char **scan;
+
+	cl_git_sandbox_init("attr");
+
+	cl_git_pass(p_mkdir("alternate", 0777));
+	cl_git_pass(p_mkdir("invalid", 0777));
+	cl_git_pass(git_futils_mkdir_r("invalid2/.git", NULL, 0777));
+
+	for (scan = bad_links; *scan != NULL; scan++) {
+		cl_git_rewritefile("alternate/.git", *scan);
+		cl_git_fail(git_repository_open_ext(&repo, "alternate", 0, NULL));
+	}
+
+	git_futils_rmdir_r("invalid", 1);
+	git_futils_rmdir_r("invalid2", 1);
+}
+
+static void unposix_path(git_buf *path)
+{
+	char *src, *tgt;
+
+	src = tgt = path->ptr;
+
+	/* convert "/d/..." to "d:\..." */
+	if (src[0] == '/' && isalpha(src[1]) && src[2] == '/') {
+		*tgt++ = src[1];
+		*tgt++ = ':';
+		*tgt++ = '\\';
+		src += 3;
+	}
+
+	while (*src) {
+		*tgt++ = (*src == '/') ? '\\' : *src;
+		src++;
+	}
+
+	*tgt = '\0';
+}
+
+void test_repo_open__win32_path(void)
+{
+#ifdef GIT_WIN32
+	git_repository *repo = cl_git_sandbox_init("empty_standard_repo"), *repo2;
+	git_buf winpath = GIT_BUF_INIT;
+	char *src, *tgt;
+	static const char *repo_path = "empty_standard_repo/.git/";
+	static const char *repo_wd   = "empty_standard_repo/";
+
+	cl_assert(git__suffixcmp(git_repository_path(repo), repo_path) == 0);
+	cl_assert(git__suffixcmp(git_repository_workdir(repo), repo_wd) == 0);
+
+	cl_git_pass(git_buf_sets(&winpath, git_repository_path(repo)));
+	unposix_path(&winpath);
+	cl_git_pass(git_repository_open(&repo2, winpath.ptr));
+	cl_assert(git__suffixcmp(git_repository_path(repo2), repo_path) == 0);
+	cl_assert(git__suffixcmp(git_repository_workdir(repo2), repo_wd) == 0);
+	git_repository_free(repo2);
+
+	cl_git_pass(git_buf_sets(&winpath, git_repository_path(repo)));
+	git_buf_truncate(&winpath, winpath.size - 1); /* remove trailing '/' */
+	unposix_path(&winpath);
+	cl_git_pass(git_repository_open(&repo2, winpath.ptr));
+	cl_assert(git__suffixcmp(git_repository_path(repo2), repo_path) == 0);
+	cl_assert(git__suffixcmp(git_repository_workdir(repo2), repo_wd) == 0);
+	git_repository_free(repo2);
+
+	cl_git_pass(git_buf_sets(&winpath, git_repository_workdir(repo)));
+	unposix_path(&winpath);
+	cl_git_pass(git_repository_open(&repo2, winpath.ptr));
+	cl_assert(git__suffixcmp(git_repository_path(repo2), repo_path) == 0);
+	cl_assert(git__suffixcmp(git_repository_workdir(repo2), repo_wd) == 0);
+	git_repository_free(repo2);
+
+	cl_git_pass(git_buf_sets(&winpath, git_repository_workdir(repo)));
+	git_buf_truncate(&winpath, winpath.size - 1); /* remove trailing '/' */
+	unposix_path(&winpath);
+	cl_git_pass(git_repository_open(&repo2, winpath.ptr));
+	cl_assert(git__suffixcmp(git_repository_path(repo2), repo_path) == 0);
+	cl_assert(git__suffixcmp(git_repository_workdir(repo2), repo_wd) == 0);
+	git_repository_free(repo2);
 
-	cl_fixture_cleanup("empty_standard_repo");
+	git_buf_free(&winpath);
+#endif
 }