coverity: fix unchecked returns#2179
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get_active_slot() duplicates the default curl handle via curl_easy_duphandle() to create a per-slot session handle. The return value is stored directly in slot->curl without checking for NULL. curl_easy_duphandle() can return NULL when memory allocation fails internally, and the libcurl documentation explicitly states this possibility. When this happens, slot->curl is NULL and the very next operation (curl_easy_setopt on line 1632 for CURLOPT_COOKIEFILE) passes NULL as the curl handle, which is undefined behavior in libcurl and typically crashes. Every HTTP operation in git goes through get_active_slot(), so this affects all remote-https, remote-http, and HTTP-based operations (clone, fetch, push over HTTP, bundle-uri downloads). Add a NULL check and die() with a clear message. There is no reasonable recovery from a failed handle duplication: the process is out of memory and cannot perform any HTTP operation. Pointed out by Coverity. Assisted-by: Claude Opus 4.6 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
show_editor() calls launch_editor() to open the user's editor on the configuration file, but discards the return value and unconditionally returns 0 (success). When the editor fails to launch (e.g., $EDITOR is not found, or the editor exits with a nonzero status), the caller receives no indication that anything went wrong. This affects "git config edit" and "git config --edit": the command silently succeeds even when the editor could not be started. In contrast, other editor-launching paths in git (such as "git commit" and "git rebase --edit-todo") properly propagate editor failures and exit with an error. Check the return value and propagate the failure by returning -1. The two callers (cmd_config_edit at line 1315 and the legacy cmd_config at line 1478) both propagate this return to handle_builtin, which translates negative returns into an error exit. Pointed out by Coverity. Assisted-by: Claude Opus 4.6 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
block_writer_init() allocates a z_stream and calls deflateInit() to prepare it for compressing log records. The return value of deflateInit() is silently discarded. If zlib initialization fails (e.g., Z_MEM_ERROR when the system is under memory pressure), the z_stream is left in an undefined state. Subsequent deflate() calls in block_writer_finish() then operate on this uninitialized stream. Depending on the zlib implementation, this can produce silently corrupted compressed data (which would be written to the reftable file and discovered only when a later reader fails to inflate) or crash outright. The function already uses REFTABLE_ZLIB_ERROR for deflate() failures later in the code path (lines 171, 199), so returning the same error code for deflateInit() failure is consistent. Pointed out by Coverity. Assisted-by: Claude Opus 4.6 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
test_reftable_table__seek_once() and test_reftable_table__reseek() both call reftable_table_init_ref_iterator() without checking its return value. This function returns an int error code (0 on success, negative on failure). Every other reftable function call in these same tests checks the return via cl_assert_equal_i() or cl_assert(), making this omission inconsistent. If the iterator initialization ever fails (e.g., due to a memory allocation failure in the reftable internals), the test would proceed to seek and read with an uninitialized iterator, producing misleading test results or crashes rather than a clear assertion failure. Check the return value via cl_assert_equal_i(ret, 0), consistent with the surrounding code. Pointed out by Coverity. Assisted-by: Claude Opus 4.6 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
last_modified_run() and process_parent() call repo_parse_commit() without checking the return value at three sites. When a commit object is corrupt or unavailable (e.g., a shallow clone boundary or a missing object in a partial clone), the parse fails and the commit's internal fields (parents, tree, date) are not populated. The consequences depend on which call site fails: At line 417 (the main walk loop), c->parents stays NULL after a failed parse. The parent-walking loop at line 440 simply does not execute, silently treating the unparsable commit as a root commit. This produces incorrect "last modified" results: paths changed in ancestors beyond the corrupt commit are attributed to the wrong commit or not reported at all. At line 423 (the --not exclusion walk), n->parents stays NULL, causing the exclusion walk to stop prematurely. Commits that should be excluded from the output may be incorrectly included. At line 293 (process_parent), the parent's tree and parents are unavailable, so diff operations against it produce wrong results and the parent's own ancestors are never enqueued for walking. Skip unparsable commits by checking the return value and continuing to the next iteration (or returning early in process_parent). This matches the defensive pattern used in other revision walkers such as limit_list() and get_revision_internal(). Pointed out by Coverity. Assisted-by: Claude Opus 4.6 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
git_pread() saves the current file offset via lseek(fd, 0, SEEK_CUR) and later restores it. If the initial lseek fails (e.g., the fd is a pipe or otherwise non-seekable), current_offset is -1. This negative value is later passed to lseek(fd, -1, SEEK_SET) at line 16, which sets the file position to an unintended location (or fails with EINVAL on some platforms). Check the initial lseek return value and return -1 immediately if it fails, consistent with the error handling for the other lseek calls in the same function. Pointed out by Coverity. Assisted-by: Claude Opus 4.6 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
get_exporter() duplicates helper->in via dup() and stores the result in fastexport->out. If dup() fails (fd exhaustion), it returns -1. The child_process machinery interprets out = -1 as "create a pipe for stdout", which would silently change the fast-export process's output wiring: instead of sending data back through the helper's input fd, it would write to a new pipe that nobody reads from. Check the return value and report the error before proceeding. Pointed out by Coverity. Assisted-by: Claude Opus 4.6 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
When push_refs_with_export() finalizes a successful push, it writes
the fast-export marks file to a .tmp sibling and rename()s it into
place. The return value of rename() is currently ignored. If the
rename fails (permission denied, full disk, or an antivirus product
locking the destination on Windows), the .tmp file is left behind
and the existing export_marks file remains stale; the next
fast-export operation that resumes from it then silently operates on
inconsistent bookkeeping.
The push itself succeeded by that point, so promoting this to a
fatal error would be inappropriate. Emit warning_errno() naming both
paths so the user can recover manually, and keep returning 0.
Flagged by Coverity as CID 1427723 ("Unchecked return value").
Assisted-by: Opus 4.7
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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>
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>
To capture the output of each verdict command, bisect_run() temporarily redirects stdout to a temporary file via the classic dup(1) / dup2() pair, restoring it afterwards. The return value of dup(1) is not checked, however. When it fails, the saved descriptor is -1, which is then passed to close() (the issue Coverity flags), and the matching dup2() that is meant to restore stdout also fails, leaving the process with stdout still pointing at the temporary file for the remainder of the run. Treat a failed dup(1) as a fatal error for this bisect step: close the temporary file descriptor, report the error via error_errno(), and break out of the loop so the existing cleanup path handles the rest, just as on other failure paths in this function. Reported by Coverity as CID 1508242 ("Improper use of negative value"). Assisted-by: Opus 4.7 Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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This is the next batch of fixes in response to issues reported by Coverity.