[PATCH v2 0/4] reftable: fix realloc error handling

Changes since v1:
- added unit tests
- explicitly set pointer to NULL on REFTABLE_ALLOC_GROW_OR_NULL failure
  in patch 2; omission found by unit test

  reftable: avoid leaks on realloc error
  reftable: fix allocation count on realloc error
  reftable: handle realloc error in parse_names()
  t-reftable-merged: handle realloc errors

 reftable/basics.c                | 14 +++-----
 reftable/basics.h                | 41 ++++++++++++++++++-----
 reftable/block.c                 | 10 +++---
 reftable/pq.c                    |  2 +-
 reftable/record.c                | 12 +++----
 reftable/stack.c                 |  8 +++--
 reftable/writer.c                |  5 +--
 t/unit-tests/t-reftable-basics.c | 56 ++++++++++++++++++++++++++++++++
 t/unit-tests/t-reftable-merged.c |  4 +--
 9 files changed, 116 insertions(+), 36 deletions(-)

Range-diff against v1:
1:  b41547720d ! 1:  b3cad92038 reftable: avoid leaks on realloc error
    @@ reftable/writer.c: static int writer_flush_nonempty_block(struct reftable_writer
      	if (!w->index)
      		return REFTABLE_OUT_OF_MEMORY_ERROR;

    +
    + ## t/unit-tests/t-reftable-basics.c ##
    +@@ t/unit-tests/t-reftable-basics.c: static int integer_needle_lesseq(size_t i, void *_args)
    + 	return args->needle <= args->haystack[i];
    + }
    +
    ++static void *realloc_stub(void *p UNUSED, size_t size UNUSED)
    ++{
    ++	return NULL;
    ++}
    ++
    + int cmd_main(int argc UNUSED, const char *argv[] UNUSED)
    + {
    + 	if_test ("binary search with binsearch works") {
    +@@ t/unit-tests/t-reftable-basics.c: int cmd_main(int argc UNUSED, const char *argv[] UNUSED)
    + 		check_int(in, ==, out);
    + 	}
    +
    ++	if_test ("REFTABLE_ALLOC_GROW_OR_NULL works") {
    ++		int *arr = NULL;
    ++		size_t alloc = 0, old_alloc;
    ++
    ++		REFTABLE_ALLOC_GROW_OR_NULL(arr, 1, alloc);
    ++		check(arr != NULL);
    ++		check_uint(alloc, >=, 1);
    ++		arr[0] = 42;
    ++
    ++		old_alloc = alloc;
    ++		REFTABLE_ALLOC_GROW_OR_NULL(arr, old_alloc + 1, alloc);
    ++		check(arr != NULL);
    ++		check_uint(alloc, >, old_alloc);
    ++		arr[alloc - 1] = 42;
    ++
    ++		old_alloc = alloc;
    ++		reftable_set_alloc(malloc, realloc_stub, free);
    ++		REFTABLE_ALLOC_GROW_OR_NULL(arr, old_alloc + 1, alloc);
    ++		check(arr == NULL);
    ++		check_uint(alloc, ==, 0);
    ++		reftable_set_alloc(malloc, realloc, free);
    ++
    ++		reftable_free(arr);
    ++	}
    ++
    + 	return test_done();
    + }
2:  bde2f0e4a5 ! 2:  62a1042825 reftable: fix allocation count on realloc error
    @@ reftable/basics.h: char *reftable_strdup(const char *str);
     -		reftable_free(reftable_alloc_grow_or_null_orig_ptr); \
     +	size_t reftable_alloc_grow_or_null_alloc = alloc; \
     +	if (REFTABLE_ALLOC_GROW((x), (nr), reftable_alloc_grow_or_null_alloc)) { \
    -+		reftable_free(x); \
    ++		REFTABLE_FREE_AND_NULL(x); \
      		alloc = 0; \
     +	} else { \
     +		alloc = reftable_alloc_grow_or_null_alloc; \
      	} \
      } while (0)

    +
    + ## t/unit-tests/t-reftable-basics.c ##
    +@@ t/unit-tests/t-reftable-basics.c: int cmd_main(int argc UNUSED, const char *argv[] UNUSED)
    + 		check_int(in, ==, out);
    + 	}
    +
    ++	if_test ("REFTABLE_ALLOC_GROW works") {
    ++		int *arr = NULL, *old_arr;
    ++		size_t alloc = 0, old_alloc;
    ++
    ++		check(!REFTABLE_ALLOC_GROW(arr, 1, alloc));
    ++		check(arr != NULL);
    ++		check_uint(alloc, >=, 1);
    ++		arr[0] = 42;
    ++
    ++		old_alloc = alloc;
    ++		old_arr = arr;
    ++		reftable_set_alloc(malloc, realloc_stub, free);
    ++		check(REFTABLE_ALLOC_GROW(arr, old_alloc + 1, alloc));
    ++		check(arr == old_arr);
    ++		check_uint(alloc, ==, old_alloc);
    ++
    ++		old_alloc = alloc;
    ++		reftable_set_alloc(malloc, realloc, free);
    ++		check(!REFTABLE_ALLOC_GROW(arr, old_alloc + 1, alloc));
    ++		check(arr != NULL);
    ++		check_uint(alloc, >, old_alloc);
    ++		arr[alloc - 1] = 42;
    ++
    ++		reftable_free(arr);
    ++	}
    ++
    + 	if_test ("REFTABLE_ALLOC_GROW_OR_NULL works") {
    + 		int *arr = NULL;
    + 		size_t alloc = 0, old_alloc;
3:  7c9f044813 = 3:  ed1a292622 reftable: handle realloc error in parse_names()
4:  3d9493f48a = 4:  916032657e t-reftable-merged: handle realloc errors
--
2.47.1