[PATCH 04/11] config: use git_config_string_dup() for open-coded equivalents

[Jeff King <peff@peff.net>]

These are cases where the calling code does the exact same thing
git_config_string_dup() would do. We can shorten the code a bit by using
it.

Note in the final case that we rely on leaving the if-else chain to
return "0" for success, and now we'll return more directly. The two are
equivalent.

Signed-off-by: Jeff King <peff@peff.net>
---
 archive-tar.c  | 10 +++-------
 compat/mingw.c |  7 ++-----
 setup.c        |  5 +----
 3 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/archive-tar.c b/archive-tar.c
index 8ae30125f8..6da7101553 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -393,13 +393,9 @@ static int tar_filter_config(const char *var, const char *value,
 		tar_filters[nr_tar_filters++] = ar;
 	}
 
-	if (!strcmp(type, "command")) {
-		if (!value)
-			return config_error_nonbool(var);
-		free(ar->filter_command);
-		ar->filter_command = xstrdup(value);
-		return 0;
-	}
+	if (!strcmp(type, "command"))
+		return git_config_string_dup(&ar->filter_command, var, value);
+
 	if (!strcmp(type, "remote")) {
 		if (git_config_bool(var, value))
 			ar->flags |= ARCHIVER_REMOTE;
diff --git a/compat/mingw.c b/compat/mingw.c
index 320fb99a90..aeccb3957f 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -255,11 +255,8 @@ int mingw_core_config(const char *var, const char *value,
 	}
 
 	if (!strcmp(var, "core.unsetenvvars")) {
-		if (!value)
-			return config_error_nonbool(var);
-		free(unset_environment_variables);
-		unset_environment_variables = xstrdup(value);
-		return 0;
+		return git_config_string_dup(&unset_environment_variables, var,
+					     value);
 	}
 
 	if (!strcmp(var, "core.restrictinheritedhandles")) {
diff --git a/setup.c b/setup.c
index 9f35a27978..7204fd2815 100644
--- a/setup.c
+++ b/setup.c
@@ -529,10 +529,7 @@ static int read_worktree_config(const char *var, const char *value,
 	if (strcmp(var, "core.bare") == 0) {
 		data->is_bare = git_config_bool(var, value);
 	} else if (strcmp(var, "core.worktree") == 0) {
-		if (!value)
-			return config_error_nonbool(var);
-		free(data->work_tree);
-		data->work_tree = xstrdup(value);
+		return git_config_string_dup(&data->work_tree, var, value);
 	}
 	return 0;
 }
-- 
2.44.0.872.g288abe5b5b