bisect: check strbuf_getline_lf return when reading terms

get_terms() in builtin/bisect.c and read_bisect_terms() in
bisect.c both read the BISECT_TERMS file but do not check the
strbuf_getline_lf() return values. If the file is truncated
(e.g., a partial write from a crash or disk-full condition),
strbuf_getline_lf returns EOF and the strbuf remains empty.
strbuf_detach then returns an empty string, and the term names
silently become "" instead of the expected "bad"/"good" or
custom terms.

In get_terms(), check for EOF and return -1 on truncation,
matching the existing -1 return for a missing file.

In read_bisect_terms(), die with a descriptive message when a
line cannot be read, consistent with the die_errno for a
non-ENOENT open failure in the same function. Unlike get_terms(),
read_bisect_terms() returns void and uses die() for all error
paths, so the die is the appropriate error handling here.

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/bisect.c b/bisect.c
index 94c7028d2a746a97196ede94ae1db7bcba1afa17..c2ef5da462f161cfcf86e63fa8864f66bde26c3d 100644 (file)
--- a/bisect.c
+++ b/bisect.c
@@ -1019,10 +1019,12 @@ void read_bisect_terms(char **read_bad, char **read_good)
                        die_errno(_("could not read file '%s'"), filename);
                }
        } else {
-               strbuf_getline_lf(&str, fp);
+               if (strbuf_getline_lf(&str, fp) == EOF)
+                       die(_("could not read bad term from file '%s'"), filename);
                free(*read_bad);
                *read_bad = strbuf_detach(&str, NULL);
-               strbuf_getline_lf(&str, fp);
+               if (strbuf_getline_lf(&str, fp) == EOF)
+                       die(_("could not read good term from file '%s'"), filename);
                free(*read_good);
                *read_good = strbuf_detach(&str, NULL);
        }

diff --git a/builtin/bisect.c b/builtin/bisect.c
index 798e28f5012d31bf76cd85be3737b450439fd092..fe66d843824713ab7d8890a4c50e512b11a2bf1a 100644 (file)
--- a/builtin/bisect.c
+++ b/builtin/bisect.c
@@ -498,9 +498,15 @@ static int get_terms(struct bisect_terms *terms)
        }
 
        free_terms(terms);
-       strbuf_getline_lf(&str, fp);
+       if (strbuf_getline_lf(&str, fp) == EOF) {
+               res = -1;
+               goto finish;
+       }
        terms->term_bad = strbuf_detach(&str, NULL);
-       strbuf_getline_lf(&str, fp);
+       if (strbuf_getline_lf(&str, fp) == EOF) {
+               res = -1;
+               goto finish;
+       }
        terms->term_good = strbuf_detach(&str, NULL);
 
 finish: