bisect: check get_terms return at all call sites

Six callers of get_terms() silently discard its return value. When
get_terms fails (missing or truncated BISECT_TERMS file), the term
strings remain NULL or empty, causing confusing downstream
behavior: commands like "bisect next" or "bisect run" proceed with
empty term strings, producing nonsensical ref names (refs/bisect/
with no suffix) and misleading error messages.

Add checks at each call site so that a failed get_terms produces a
clear "no terms defined" error, matching the pattern already used
in bisect_terms() at line 512. The check tests the term pointers
rather than the return value because some callers (bisect skip,
legacy bad/good) call set_terms before get_terms, and the
set_terms values should survive a get_terms failure.

Pointed out by Coverity.

Assisted-by: Claude Opus 4.6
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/bisect.c b/builtin/bisect.c
index fe66d843824713ab7d8890a4c50e512b11a2bf1a..15a2a30f897b07f0b5d520158fad326624e5b712 100644 (file)
--- a/builtin/bisect.c
+++ b/builtin/bisect.c
@@ -1057,6 +1057,8 @@ static int process_replay_line(struct bisect_terms *terms, struct strbuf *line)
        *word_end = '\0'; /* NUL-terminate the word */
 
        get_terms(terms);
+       if (!terms->term_bad || !terms->term_good)
+               return error(_("no terms defined"));
        if (check_and_set_terms(terms, p))
                return -1;
 
@@ -1383,6 +1385,8 @@ static int cmd_bisect__next(int argc, const char **argv UNUSED, const char *pref
                return error(_("'%s' requires 0 arguments"),
                             "git bisect next");
        get_terms(&terms);
+       if (!terms.term_bad || !terms.term_good)
+               return error(_("no terms defined"));
        res = bisect_next(&terms, prefix);
        free_terms(&terms);
        return res;
@@ -1417,6 +1421,8 @@ static int cmd_bisect__skip(int argc, const char **argv, const char *prefix UNUS
 
        set_terms(&terms, "bad", "good");
        get_terms(&terms);
+       if (!terms.term_bad || !terms.term_good)
+               return error(_("no terms defined"));
        res = bisect_skip(&terms, argc, argv);
        free_terms(&terms);
        return res;
@@ -1429,6 +1435,8 @@ static int cmd_bisect__visualize(int argc, const char **argv, const char *prefix
        struct bisect_terms terms = { 0 };
 
        get_terms(&terms);
+       if (!terms.term_bad || !terms.term_good)
+               return error(_("no terms defined"));
        res = bisect_visualize(&terms, argc, argv);
        free_terms(&terms);
        return res;
@@ -1443,6 +1451,8 @@ static int cmd_bisect__run(int argc, const char **argv, const char *prefix UNUSE
        if (!argc)
                return error(_("'%s' failed: no command provided."), "git bisect run");
        get_terms(&terms);
+       if (!terms.term_bad || !terms.term_good)
+               return error(_("no terms defined"));
        res = bisect_run(&terms, argc, argv);
        free_terms(&terms);
        return res;
@@ -1482,6 +1492,8 @@ int cmd_bisect(int argc,
 
                set_terms(&terms, "bad", "good");
                get_terms(&terms);
+               if (!terms.term_bad || !terms.term_good)
+                       return error(_("no terms defined"));
                if (check_and_set_terms(&terms, argv[0]) ||
                    !one_of(argv[0], terms.term_good, terms.term_bad, NULL))
                        usage_msg_optf(_("unknown command: '%s'"), git_bisect_usage,