trace2: prevent segfault on config collection with valueless true

When TRACE2 analytics is enabled, a configuration variable set to
"valueless true" causes a segfault.

Steps to Reproduce

    GIT_TRACE2=true GIT_TRACE2_CONFIG_PARAMS=status.*
    git -c status.relativePaths version
    Expected Result
    git version 2.46.0
    Actual Result
    zsh: segmentation fault GIT_TRACE2=true

Add checks to prevent the segfault and instead show that the
variable without value.

Signed-off-by: Adam Murray <ad@canva.com>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/trace2.c b/trace2.c
index f894532d05..e67edf4b1b 100644
--- a/trace2.c
+++ b/trace2.c
@@ -762,7 +762,7 @@ void trace2_def_param_fl(const char *file, int line, const char *param,
 	if (!trace2_enabled)
 		return;
 
-	redacted = redact_arg(value);
+	redacted = value ? redact_arg(value) : NULL;
 
 	for_each_wanted_builtin (j, tgt_j)
 		if (tgt_j->pfn_param_fl)