Merge branch 'ps/setup-split-discovery-and-setup' into jch

The repository discovery and repository configuration phases, which
were previously intertwined in 'setup.c', have been split. Repository
discovery now populates a 'struct repo_discovery' without modifying
the repository state, and repository configuration takes this
structure to initialize the repository, paving the way for clean
unification of repository configuration.

* ps/setup-split-discovery-and-setup:
  setup: mark `set_git_work_tree()` as file-local
  setup: pass worktree to `init_db()`
  setup: drop redundant configuration of `startup_info->have_repository`
  setup: make repository discovery self-contained
  setup: propagate prefix via repository discovery
  setup: drop static `cwd` variable
  setup: move prefix into repository
  setup: embed repository format in discovery
  setup: introduce explicit repository discovery
  setup: split up concerns of `setup_git_env_internal()`
  setup: unify setup of shallow file
  setup: mark bogus worktree in `apply_repository_format()`
  setup: rename `check_repository_format_gently()`

Author: gitster

builtin/clone.c

@@ -1116,7 +1116,6 @@ int cmd_clone(int argc,
 			die_errno(_("could not create work tree dir '%s'"),
 				  work_tree);
 		junk_work_tree = work_tree;
-		set_git_work_tree(the_repository, work_tree);
 	}
 
 	if (real_git_dir) {
@@ -1186,9 +1185,10 @@ int cmd_clone(int argc,
 	 * repository, and reference backends may persist that information into
 	 * their on-disk data structures.
 	 */
-	init_db(the_repository, git_dir, real_git_dir, option_template, GIT_HASH_UNKNOWN,
-		ref_storage_format, NULL,
-		do_not_override_repo_unix_permissions, INIT_DB_QUIET | INIT_DB_SKIP_REFDB);
+	init_db(the_repository, git_dir, real_git_dir, work_tree, option_template,
+		GIT_HASH_UNKNOWN, ref_storage_format, NULL,
+		do_not_override_repo_unix_permissions,
+		INIT_DB_QUIET | INIT_DB_SKIP_REFDB);
 
 	if (real_git_dir) {
 		free((char *)git_dir);

builtin/init-db.c

@@ -231,39 +231,25 @@ int cmd_init_db(int argc,
 	if (!bare) {
 		const char *git_dir_parent = strrchr(git_dir, '/');
 
-		if (work_tree) {
-			set_git_work_tree(the_repository, work_tree);
-		} else {
-			char *work_tree_cfg = NULL;
-
+		if (!work_tree) {
 			if (git_dir_parent) {
 				char *rel = xstrndup(git_dir, git_dir_parent - git_dir);
-				work_tree_cfg = real_pathdup(rel, 1);
+				work_tree = real_pathdup(rel, 1);
 				free(rel);
+			} else {
+				work_tree = xgetcwd();
 			}
-
-			if (!work_tree_cfg)
-				work_tree_cfg = xgetcwd();
-
-			set_git_work_tree(the_repository, work_tree_cfg);
-
-			free(work_tree_cfg);
 		}
 
-		if (access(repo_get_work_tree(the_repository), X_OK))
-			die_errno (_("Cannot access work tree '%s'"),
-				   repo_get_work_tree(the_repository));
-	}
-	else {
-		if (real_git_dir)
-			die(_("--separate-git-dir incompatible with bare repository"));
-		if (work_tree)
-			set_git_work_tree(the_repository, work_tree);
+		if (access(work_tree, X_OK))
+			die_errno (_("Cannot access work tree '%s'"), work_tree);
+	} else if (real_git_dir) {
+		die(_("--separate-git-dir incompatible with bare repository"));
 	}
 
 	flags |= INIT_DB_EXIST_OK;
-	ret = init_db(the_repository, git_dir, real_git_dir, template_dir, hash_algo,
-		      ref_storage_format, initial_branch,
+	ret = init_db(the_repository, git_dir, real_git_dir, work_tree,
+		      template_dir, hash_algo, ref_storage_format, initial_branch,
 		      init_shared_repository, flags);
 
 	free(template_dir_to_free);

builtin/repo.c

@@ -84,7 +84,7 @@ static int get_path_commondir_absolute(struct repository *repo, struct strbuf *b
 	if (!common_dir)
 		return error(_("unable to get common directory"));
 
-	format_path(buf, common_dir, startup_info->prefix, PATH_FORMAT_CANONICAL);
+	format_path(buf, common_dir, repo->prefix, PATH_FORMAT_CANONICAL);
 	return 0;
 }
 
@@ -95,7 +95,7 @@ static int get_path_commondir_relative(struct repository *repo, struct strbuf *b
 	if (!common_dir)
 		return error(_("unable to get common directory"));
 
-	format_path(buf, common_dir, startup_info->prefix, PATH_FORMAT_RELATIVE);
+	format_path(buf, common_dir, repo->prefix, PATH_FORMAT_RELATIVE);
 	return 0;
 }
 
@@ -106,7 +106,7 @@ static int get_path_gitdir_absolute(struct repository *repo, struct strbuf *buf)
 	if (!git_dir)
 		return error(_("unable to get git directory"));
 
-	format_path(buf, git_dir, startup_info->prefix, PATH_FORMAT_CANONICAL);
+	format_path(buf, git_dir, repo->prefix, PATH_FORMAT_CANONICAL);
 	return 0;
 }
 
@@ -117,7 +117,7 @@ static int get_path_gitdir_relative(struct repository *repo, struct strbuf *buf)
 	if (!git_dir)
 		return error(_("unable to get git directory"));
 
-	format_path(buf, git_dir, startup_info->prefix, PATH_FORMAT_RELATIVE);
+	format_path(buf, git_dir, repo->prefix, PATH_FORMAT_RELATIVE);
 	return 0;
 }
 

builtin/rev-parse.c

@@ -255,7 +255,7 @@ static int show_file(const char *arg, int output_prefix)
 	show_default();
 	if ((filter & (DO_NONFLAGS|DO_NOREV)) == (DO_NONFLAGS|DO_NOREV)) {
 		if (output_prefix) {
-			const char *prefix = startup_info->prefix;
+			const char *prefix = the_repository->prefix;
 			char *fname = prefix_filename(prefix, arg);
 			show(fname);
 			free(fname);
@@ -832,7 +832,8 @@ int cmd_rev_parse(int argc,
 				prefix = argv[++i];
 				if (!prefix)
 					die(_("--prefix requires an argument"));
-				startup_info->prefix = prefix;
+				FREE_AND_NULL(the_repository->prefix);
+				the_repository->prefix = xstrdup(prefix);
 				output_prefix = 1;
 				continue;
 			}

builtin/update-index.c

@@ -875,7 +875,7 @@ static enum parse_opt_result unresolve_callback(
 	const char *arg, int unset)
 {
 	int *has_errors = opt->value;
-	const char *prefix = startup_info->prefix;
+	const char *prefix = the_repository->prefix;
 
 	BUG_ON_OPT_NEG(unset);
 	BUG_ON_OPT_ARG(arg);
@@ -896,7 +896,7 @@ static enum parse_opt_result reupdate_callback(
 	const char *arg, int unset)
 {
 	int *has_errors = opt->value;
-	const char *prefix = startup_info->prefix;
+	const char *prefix = the_repository->prefix;
 
 	BUG_ON_OPT_NEG(unset);
 	BUG_ON_OPT_ARG(arg);

common-init.c

@@ -5,7 +5,10 @@
 #include "exec-cmd.h"
 #include "gettext.h"
 #include "attr.h"
+#include "odb.h"
+#include "parse.h"
 #include "repository.h"
+#include "replace-object.h"
 #include "setup.h"
 #include "strbuf.h"
 #include "trace2.h"
@@ -31,6 +34,22 @@ static void restore_sigpipe_to_default(void)
 	signal(SIGPIPE, SIG_DFL);
 }
 
+static void setup_environment(void)
+{
+	char *git_replace_ref_base;
+	const char *replace_ref_base;
+
+	if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
+		disable_replace_refs();
+	replace_ref_base = getenv(GIT_REPLACE_REF_BASE_ENVIRONMENT);
+	git_replace_ref_base = xstrdup(replace_ref_base ? replace_ref_base
+							  : "refs/replace/");
+	update_ref_namespace(NAMESPACE_REPLACE, git_replace_ref_base);
+
+	if (git_env_bool(NO_LAZY_FETCH_ENVIRONMENT, 0))
+		fetch_if_missing = 0;
+}
+
 void init_git(const char **argv)
 {
 	struct strbuf tmp = STRBUF_INIT;
@@ -51,6 +70,7 @@ void init_git(const char **argv)
 	git_setup_gettext();
 
 	initialize_repository(the_repository);
+	setup_environment();
 
 	attr_start();
 

git.c

@@ -306,7 +306,7 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 		} else if (!strcmp(cmd, "--shallow-file")) {
 			(*argv)++;
 			(*argc)--;
-			set_alternate_shallow_file(the_repository, (*argv)[0], 1);
+			setenv(GIT_SHALLOW_FILE_ENVIRONMENT, (*argv)[0], 1);
 			if (envchanged)
 				*envchanged = 1;
 		} else if (!strcmp(cmd, "-C")) {

object-name.c

@@ -1708,8 +1708,8 @@ static char *resolve_relative_path(struct repository *r, const char *rel)
 		die(_("relative path syntax can't be used outside working tree"));
 
 	/* die() inside prefix_path() if resolved path is outside worktree */
-	return prefix_path(the_repository, startup_info->prefix,
-			   startup_info->prefix ? strlen(startup_info->prefix) : 0,
+	return prefix_path(the_repository, the_repository->prefix,
+			   the_repository->prefix ? strlen(the_repository->prefix) : 0,
 			   rel);
 }
 

repository.c

@@ -376,6 +376,7 @@ void repo_clear(struct repository *repo)
 
 	FREE_AND_NULL(repo->gitdir);
 	FREE_AND_NULL(repo->commondir);
+	FREE_AND_NULL(repo->prefix);
 	FREE_AND_NULL(repo->graft_file);
 	FREE_AND_NULL(repo->index_file);
 	FREE_AND_NULL(repo->worktree);

repository.h

@@ -52,6 +52,14 @@ struct repository {
 	 */
 	char *commondir;
 
+	/*
+	 * The "prefix", a path to the current working directory relative to
+	 * the work tree root, or NULL, if the current working directory is not
+	 * a strict subdirectory of the work tree root. The prefix always ends
+	 * with a '/' character.
+	 */
+	char *prefix;
+
 	/*
 	 * Holds any information related to accessing the raw object content.
 	 */