Merge branch 'bc/more-git-var'

Add more "git var" for toolsmiths to learn various locations Git is
configured with either via the configuration or hardcoded defaults.

* bc/more-git-var:
  var: add config file locations
  var: add attributes files locations
  attr: expose and rename accessor functions
  var: adjust memory allocation for strings
  var: format variable structure with C99 initializers
  var: add support for listing the shell
  t: add a function to check executable bit
  var: mark unused parameters in git_var callbacks

7 files changed, 303 insertions, 27 deletions

diff --git a/Documentation/git-var.txt b/Documentation/git-var.txt
index f40202b8e3..c38fb3968b 100644
--- a/Documentation/git-var.txt
+++ b/Documentation/git-var.txt
@@ -71,6 +71,29 @@ endif::git-default-pager[]
 GIT_DEFAULT_BRANCH::
     The name of the first branch created in newly initialized repositories.
 
+GIT_SHELL_PATH::
+    The path of the binary providing the POSIX shell for commands which use the shell.
+
+GIT_ATTR_SYSTEM::
+    The path to the system linkgit:gitattributes[5] file, if one is enabled.
+
+GIT_ATTR_GLOBAL::
+    The path to the global (per-user) linkgit:gitattributes[5] file.
+
+GIT_CONFIG_SYSTEM::
+    The path to the system configuration file, if one is enabled.
+
+GIT_CONFIG_GLOBAL::
+    The path to the global (per-user) configuration files, if any.
+
+Most path values contain only one value. However, some can contain multiple
+values, which are separated by newlines, and are listed in order from highest to
+lowest priority.  Callers should be prepared for any such path value to contain
+multiple items.
+
+Note that paths are printed even if they do not exist, but not if they are
+disabled by other environment variables.
+
 SEE ALSO
 --------
 linkgit:git-commit-tree[1]
diff --git a/attr.c b/attr.c
index 7d39ac4a29..e5785c55db 100644
--- a/attr.c
+++ b/attr.c
@@ -872,7 +872,7 @@ static struct attr_stack *read_attr(struct index_state *istate,
 	return res;
 }
 
-static const char *git_etc_gitattributes(void)
+const char *git_attr_system_file(void)
 {
 	static const char *system_wide;
 	if (!system_wide)
@@ -880,7 +880,7 @@ static const char *git_etc_gitattributes(void)
 	return system_wide;
 }
 
-static const char *get_home_gitattributes(void)
+const char *git_attr_global_file(void)
 {
 	if (!git_attributes_file)
 		git_attributes_file = xdg_config_home("attributes");
@@ -888,7 +888,7 @@ static const char *get_home_gitattributes(void)
 	return git_attributes_file;
 }
 
-static int git_attr_system(void)
+int git_attr_system_is_enabled(void)
 {
 	return !git_env_bool("GIT_ATTR_NOSYSTEM", 0);
 }
@@ -922,14 +922,14 @@ static void bootstrap_attr_stack(struct index_state *istate,
 	push_stack(stack, e, NULL, 0);
 
 	/* system-wide frame */
-	if (git_attr_system()) {
-		e = read_attr_from_file(git_etc_gitattributes(), flags);
+	if (git_attr_system_is_enabled()) {
+		e = read_attr_from_file(git_attr_system_file(), flags);
 		push_stack(stack, e, NULL, 0);
 	}
 
 	/* home directory */
-	if (get_home_gitattributes()) {
-		e = read_attr_from_file(get_home_gitattributes(), flags);
+	if (git_attr_global_file()) {
+		e = read_attr_from_file(git_attr_global_file(), flags);
 		push_stack(stack, e, NULL, 0);
 	}
 
diff --git a/attr.h b/attr.h
index 676bd17ce2..2b745df405 100644
--- a/attr.h
+++ b/attr.h
@@ -227,4 +227,13 @@ void git_attr_set_direction(enum git_attr_direction new_direction);
 
 void attr_start(void);
 
+/* Return the system gitattributes file. */
+const char *git_attr_system_file(void);
+
+/* Return the global gitattributes file, if any. */
+const char *git_attr_global_file(void);
+
+/* Return whether the system gitattributes file is enabled and should be used. */
+int git_attr_system_is_enabled(void);
+
 #endif /* ATTR_H */
diff --git a/builtin/var.c b/builtin/var.c
index 2149998980..3e3d4a6ebf 100644
--- a/builtin/var.c
+++ b/builtin/var.c
@@ -4,60 +4,188 @@
  * Copyright (C) Eric Biederman, 2005
  */
 #include "builtin.h"
+#include "attr.h"
 #include "config.h"
 #include "editor.h"
 #include "ident.h"
 #include "pager.h"
 #include "refs.h"
+#include "path.h"
+#include "strbuf.h"
 
 static const char var_usage[] = "git var (-l | <variable>)";
 
-static const char *editor(int flag)
+static char *committer(int ident_flag)
 {
-	return git_editor();
+	return xstrdup_or_null(git_committer_info(ident_flag));
 }
 
-static const char *sequence_editor(int flag)
+static char *author(int ident_flag)
 {
-	return git_sequence_editor();
+	return xstrdup_or_null(git_author_info(ident_flag));
 }
 
-static const char *pager(int flag)
+static char *editor(int ident_flag UNUSED)
+{
+	return xstrdup_or_null(git_editor());
+}
+
+static char *sequence_editor(int ident_flag UNUSED)
+{
+	return xstrdup_or_null(git_sequence_editor());
+}
+
+static char *pager(int ident_flag UNUSED)
 {
 	const char *pgm = git_pager(1);
 
 	if (!pgm)
 		pgm = "cat";
-	return pgm;
+	return xstrdup(pgm);
+}
+
+static char *default_branch(int ident_flag UNUSED)
+{
+	return xstrdup_or_null(git_default_branch_name(1));
+}
+
+static char *shell_path(int ident_flag UNUSED)
+{
+	return xstrdup(SHELL_PATH);
 }
 
-static const char *default_branch(int flag)
+static char *git_attr_val_system(int ident_flag UNUSED)
 {
-	return git_default_branch_name(1);
+	if (git_attr_system_is_enabled()) {
+		char *file = xstrdup(git_attr_system_file());
+		normalize_path_copy(file, file);
+		return file;
+	}
+	return NULL;
+}
+
+static char *git_attr_val_global(int ident_flag UNUSED)
+{
+	char *file = xstrdup(git_attr_global_file());
+	if (file) {
+		normalize_path_copy(file, file);
+		return file;
+	}
+	return NULL;
+}
+
+static char *git_config_val_system(int ident_flag UNUSED)
+{
+	if (git_config_system()) {
+		char *file = git_system_config();
+		normalize_path_copy(file, file);
+		return file;
+	}
+	return NULL;
+}
+
+static char *git_config_val_global(int ident_flag UNUSED)
+{
+	struct strbuf buf = STRBUF_INIT;
+	char *user, *xdg;
+	size_t unused;
+
+	git_global_config(&user, &xdg);
+	if (xdg && *xdg) {
+		normalize_path_copy(xdg, xdg);
+		strbuf_addf(&buf, "%s\n", xdg);
+	}
+	if (user && *user) {
+		normalize_path_copy(user, user);
+		strbuf_addf(&buf, "%s\n", user);
+	}
+	free(xdg);
+	free(user);
+	strbuf_trim_trailing_newline(&buf);
+	if (buf.len == 0) {
+		strbuf_release(&buf);
+		return NULL;
+	}
+	return strbuf_detach(&buf, &unused);
 }
 
 struct git_var {
 	const char *name;
-	const char *(*read)(int);
+	char *(*read)(int);
+	int multivalued;
 };
 static struct git_var git_vars[] = {
-	{ "GIT_COMMITTER_IDENT", git_committer_info },
-	{ "GIT_AUTHOR_IDENT",   git_author_info },
-	{ "GIT_EDITOR", editor },
-	{ "GIT_SEQUENCE_EDITOR", sequence_editor },
-	{ "GIT_PAGER", pager },
-	{ "GIT_DEFAULT_BRANCH", default_branch },
-	{ "", NULL },
+	{
+		.name = "GIT_COMMITTER_IDENT",
+		.read = committer,
+	},
+	{
+		.name = "GIT_AUTHOR_IDENT",
+		.read = author,
+	},
+	{
+		.name = "GIT_EDITOR",
+		.read = editor,
+	},
+	{
+		.name = "GIT_SEQUENCE_EDITOR",
+		.read = sequence_editor,
+	},
+	{
+		.name = "GIT_PAGER",
+		.read = pager,
+	},
+	{
+		.name = "GIT_DEFAULT_BRANCH",
+		.read = default_branch,
+	},
+	{
+		.name = "GIT_SHELL_PATH",
+		.read = shell_path,
+	},
+	{
+		.name = "GIT_ATTR_SYSTEM",
+		.read = git_attr_val_system,
+	},
+	{
+		.name = "GIT_ATTR_GLOBAL",
+		.read = git_attr_val_global,
+	},
+	{
+		.name = "GIT_CONFIG_SYSTEM",
+		.read = git_config_val_system,
+	},
+	{
+		.name = "GIT_CONFIG_GLOBAL",
+		.read = git_config_val_global,
+		.multivalued = 1,
+	},
+	{
+		.name = "",
+		.read = NULL,
+	},
 };
 
 static void list_vars(void)
 {
 	struct git_var *ptr;
-	const char *val;
+	char *val;
 
 	for (ptr = git_vars; ptr->read; ptr++)
-		if ((val = ptr->read(0)))
-			printf("%s=%s\n", ptr->name, val);
+		if ((val = ptr->read(0))) {
+			if (ptr->multivalued && *val) {
+				struct string_list list = STRING_LIST_INIT_DUP;
+				int i;
+
+				string_list_split(&list, val, '\n', -1);
+				for (i = 0; i < list.nr; i++)
+					printf("%s=%s\n", ptr->name, list.items[i].string);
+				string_list_clear(&list, 0);
+			} else {
+				printf("%s=%s\n", ptr->name, val);
+			}
+			free(val);
+		}
 }
 
 static const struct git_var *get_git_var(const char *var)
@@ -83,7 +211,7 @@ static int show_config(const char *var, const char *value, void *cb)
 int cmd_var(int argc, const char **argv, const char *prefix UNUSED)
 {
 	const struct git_var *git_var;
-	const char *val;
+	char *val;
 
 	if (argc != 2)
 		usage(var_usage);
@@ -104,6 +232,7 @@ int cmd_var(int argc, const char **argv, const char *prefix UNUSED)
 		return 1;
 
 	printf("%s\n", val);
+	free(val);
 
 	return 0;
 }
diff --git a/t/README b/t/README
index b71a065e4a..6108085989 100644
--- a/t/README
+++ b/t/README
@@ -1102,6 +1102,12 @@ see test-lib-functions.sh for the full list and their options.
    the symbolic link in the file system and a part that does; then only
    the latter part need be protected by a SYMLINKS prerequisite (see below).
 
+ - test_path_is_executable
+
+   This tests whether a file is executable and prints an error message
+   if not. This must be used only under the POSIXPERM prerequisite
+   (see below).
+
  - test_oid_init
 
    This function loads facts and useful object IDs related to the hash
diff --git a/t/t0007-git-var.sh b/t/t0007-git-var.sh
index eeb8539c1b..8cb597f99c 100755
--- a/t/t0007-git-var.sh
+++ b/t/t0007-git-var.sh
@@ -147,6 +147,84 @@ test_expect_success 'get GIT_SEQUENCE_EDITOR with configuration and environment
 	)
 '
 
+test_expect_success POSIXPERM 'GIT_SHELL_PATH points to a valid executable' '
+	shellpath=$(git var GIT_SHELL_PATH) &&
+	test_path_is_executable "$shellpath"
+'
+
+# We know in this environment that our shell will be one of a few fixed values
+# that all end in "sh".
+test_expect_success MINGW 'GIT_SHELL_PATH points to a suitable shell' '
+	shellpath=$(git var GIT_SHELL_PATH) &&
+	case "$shellpath" in
+	*sh) ;;
+	*) return 1;;
+	esac
+'
+
+test_expect_success 'GIT_ATTR_SYSTEM produces expected output' '
+	test_must_fail env GIT_ATTR_NOSYSTEM=1 git var GIT_ATTR_SYSTEM &&
+	(
+		sane_unset GIT_ATTR_NOSYSTEM &&
+		systempath=$(git var GIT_ATTR_SYSTEM) &&
+		test "$systempath" != ""
+	)
+'
+
+test_expect_success 'GIT_ATTR_GLOBAL points to the correct location' '
+	TRASHDIR="$(test-tool path-utils normalize_path_copy "$(pwd)")" &&
+	globalpath=$(XDG_CONFIG_HOME="$TRASHDIR/.config" git var GIT_ATTR_GLOBAL) &&
+	test "$globalpath" = "$TRASHDIR/.config/git/attributes" &&
+	(
+		sane_unset XDG_CONFIG_HOME &&
+		globalpath=$(HOME="$TRASHDIR" git var GIT_ATTR_GLOBAL) &&
+		test "$globalpath" = "$TRASHDIR/.config/git/attributes"
+	)
+'
+
+test_expect_success 'GIT_CONFIG_SYSTEM points to the correct location' '
+	TRASHDIR="$(test-tool path-utils normalize_path_copy "$(pwd)")" &&
+	test_must_fail env GIT_CONFIG_NOSYSTEM=1 git var GIT_CONFIG_SYSTEM &&
+	(
+		sane_unset GIT_CONFIG_NOSYSTEM &&
+		systempath=$(git var GIT_CONFIG_SYSTEM) &&
+		test "$systempath" != "" &&
+		systempath=$(GIT_CONFIG_SYSTEM=/dev/null git var GIT_CONFIG_SYSTEM) &&
+		if test_have_prereq MINGW
+		then
+			test "$systempath" = "nul"
+		else
+			test "$systempath" = "/dev/null"
+		fi &&
+		systempath=$(GIT_CONFIG_SYSTEM="$TRASHDIR/gitconfig" git var GIT_CONFIG_SYSTEM) &&
+		test "$systempath" = "$TRASHDIR/gitconfig"
+	)
+'
+
+test_expect_success 'GIT_CONFIG_GLOBAL points to the correct location' '
+	TRASHDIR="$(test-tool path-utils normalize_path_copy "$(pwd)")" &&
+	HOME="$TRASHDIR" XDG_CONFIG_HOME="$TRASHDIR/foo" git var GIT_CONFIG_GLOBAL >actual &&
+	echo "$TRASHDIR/foo/git/config" >expected &&
+	echo "$TRASHDIR/.gitconfig" >>expected &&
+	test_cmp expected actual &&
+	(
+		sane_unset XDG_CONFIG_HOME &&
+		HOME="$TRASHDIR" git var GIT_CONFIG_GLOBAL >actual &&
+		echo "$TRASHDIR/.config/git/config" >expected &&
+		echo "$TRASHDIR/.gitconfig" >>expected &&
+		test_cmp expected actual &&
+		globalpath=$(GIT_CONFIG_GLOBAL=/dev/null git var GIT_CONFIG_GLOBAL) &&
+		if test_have_prereq MINGW
+		then
+			test "$globalpath" = "nul"
+		else
+			test "$globalpath" = "/dev/null"
+		fi &&
+		globalpath=$(GIT_CONFIG_GLOBAL="$TRASHDIR/gitconfig" git var GIT_CONFIG_GLOBAL) &&
+		test "$globalpath" = "$TRASHDIR/gitconfig"
+	)
+'
+
 # For git var -l, we check only a representative variable;
 # testing the whole output would make our test too brittle with
 # respect to unrelated changes in the test suite's environment.
@@ -164,6 +242,28 @@ test_expect_success 'git var -l lists config' '
 	test_cmp expect actual.bare
 '
 
+test_expect_success 'git var -l lists multiple global configs' '
+	TRASHDIR="$(test-tool path-utils normalize_path_copy "$(pwd)")" &&
+	HOME="$TRASHDIR" XDG_CONFIG_HOME="$TRASHDIR/foo" git var -l >actual &&
+	grep "^GIT_CONFIG_GLOBAL=" actual >filtered &&
+	echo "GIT_CONFIG_GLOBAL=$TRASHDIR/foo/git/config" >expected &&
+	echo "GIT_CONFIG_GLOBAL=$TRASHDIR/.gitconfig" >>expected &&
+	test_cmp expected filtered
+'
+
+test_expect_success 'git var -l does not split multiline editors' '
+	(
+		GIT_EDITOR="!f() {
+			echo Hello!
+		}; f" &&
+		export GIT_EDITOR &&
+		echo "GIT_EDITOR=$GIT_EDITOR" >expected &&
+		git var -l >var &&
+		sed -n -e "/^GIT_EDITOR/,\$p" var | head -n 3 >actual &&
+		test_cmp expected actual
+	)
+'
+
 test_expect_success 'listing and asking for variables are exclusive' '
 	test_must_fail git var -l GIT_COMMITTER_IDENT
 '
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index b3864e22e9..2fa716c567 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -910,6 +910,15 @@ test_path_is_symlink () {
 	fi
 }
 
+test_path_is_executable () {
+	test "$#" -ne 1 && BUG "1 param"
+	if ! test -x "$1"
+	then
+		echo "$1 is not executable"
+		false
+	fi
+}
+
 # Check if the directory exists and is empty as expected, barf otherwise.
 test_dir_is_empty () {
 	test "$#" -ne 1 && BUG "1 param"