[1/3] var: do not print usage() with a correct invocation

Commit Message

Sean Allred Nov. 24, 2022, 8:22 p.m. UTC

From: Sean Allred <[e-mail]>

Before, git-var could print usage() even if the command was invoked
correctly with a variable defined in git_vars -- provided that its
read() function returned NULL.

Now, we only print usage() only if it was called with a logical
variable that wasn't defined -- regardless of read().

Since we now know the variable is valid when we call read_var(), we
can avoid printing usage() here (and exiting with code 129) and
instead exit quietly with code 1. While exiting with a different code
can be a breaking change, it's far better than changing the exit
status more generally from 'failure' to 'success'.

Signed-off-by: Sean Allred <[e-mail]>
---
 Documentation/git-var.txt |  3 ++-
 builtin/var.c             | 19 ++++++++++++++++++-
 2 files changed, 20 insertions(+), 2 deletions(-)

Patch

diff --git a/Documentation/git-var.txt b/Documentation/git-var.txt
index 6aa521fab23..0ab5bfa7d72 100644
--- a/Documentation/git-var.txt
+++ b/Documentation/git-var.txt
@@ -13,7 +13,8 @@  SYNOPSIS
 
 DESCRIPTION
 -----------
-Prints a Git logical variable.
+Prints a Git logical variable. Exits with code 1 if the variable has
+no value.
 
 OPTIONS
 -------
diff --git a/builtin/var.c b/builtin/var.c
index 491db274292..776f1778ae1 100644
--- a/builtin/var.c
+++ b/builtin/var.c
@@ -56,6 +56,17 @@  static void list_vars(void)
 			printf("%s=%s\n", ptr->name, val);
 }
 
+static const struct git_var *get_git_var(const char *var)
+{
+	struct git_var *ptr;
+	for (ptr = git_vars; ptr->read; ptr++) {
+		if (strcmp(var, ptr->name) == 0) {
+			return ptr;
+		}
+	}
+	return NULL;
+}
+
 static const char *read_var(const char *var)
 {
 	struct git_var *ptr;
@@ -81,6 +92,7 @@  static int show_config(const char *var, const char *value, void *cb)
 
 int cmd_var(int argc, const char **argv, const char *prefix)
 {
+	const struct git_var *git_var = NULL;
 	const char *val = NULL;
 	if (argc != 2)
 		usage(var_usage);
@@ -91,9 +103,14 @@  int cmd_var(int argc, const char **argv, const char *prefix)
 		return 0;
 	}
 	git_config(git_default_config, NULL);
+
+	git_var = get_git_var(argv[1]);
+	if (!git_var)
+		usage(var_usage);
+
 	val = read_var(argv[1]);
 	if (!val)
-		usage(var_usage);
+		return 1;
 
 	printf("%s\n", val);