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[PATCH v3 08/27] line-log: fix leak when rewriting commit parents

From
Patrick Steinhardt <ps@pks.im>
Date
Nov 20, 2024, 13:39 UTC
Message-ID
<20241120-b4-pks-leak-fixes-pt10-v3-8-d67f08f45c74@pks.im>
In-Reply-To
<20241120-b4-pks-leak-fixes-pt10-v3-0-d67f08f45c74@pks.im>

In `process_ranges_merge_commit()` we try to figure out which of the parents can be blamed for the given line changes. When we figure out that none of the files in the line-log have changed we assign the complete blame to that commit and rewrite the parents of the current commit to only use that single parent.

This is done via `commit_list_append()`, which is misleadingly _not_ appending to the list of parents. Instead, we overwrite the parents with the blamed parent. This makes us lose track of the old pointers, creating a memory leak.

Fix this issue by freeing the parents before we overwrite them.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 line-log.c          | 1 +
 t/t4211-line-log.sh | 1 +
 2 files changed, 2 insertions(+)
diff --git a/line-log.c b/line-log.c
index bca9bd804073df9b77b2859063ac5ad4d3b24e0f..bc67b75d10d34edc726c00c887d57016e40f3a00 100644
--- a/line-log.c
+++ b/line-log.c
@@ -1237,6 +1237,7 @@ static int process_ranges_merge_commit(struct rev_info *rev, struct commit *comm
 			 * don't follow any other path in history
 			 */
 			add_line_range(rev, parents[i], cand[i]);
+			free_commit_list(commit->parents);
 			commit_list_append(parents[i], &commit->parents);
 
 			ret = 0;
diff --git a/t/t4211-line-log.sh b/t/t4211-line-log.sh
index 950451cf6a66e6c099aa5303ce19230c34cd1fc4..1d6dd982a2a858e9ca03635eb83b1463c9c9caed 100755
--- a/t/t4211-line-log.sh
+++ b/t/t4211-line-log.sh
@@ -4,6 +4,7 @@ test_description='test log -L'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup (import history)' '
-- 
2.47.0.274.g962d0b743d.dirty
Previous: Patrick SteinhardtNext: Patrick Steinhardt
Message 13 of 33 in “Memory leak fixes (pt.10, final)”
  1. 00/27 Memory leak fixes (pt.10, final)Patrick Steinhardt, Nov 20, 2024
  2. 01/27 builtin/blame: fix leaking blame entries with `--incremental`Patrick Steinhardt, Nov 20, 2024
  3. 02/27 bisect: fix leaking good/bad terms when reading multipe timesPatrick Steinhardt, Nov 20, 2024
  4. 04/27 bisect: fix leaking `current_bad_oid`Patrick Steinhardt, Nov 20, 2024
  5. 03/27 bisect: fix leaking string in `handle_bad_merge_base()`Patrick Steinhardt, Nov 20, 2024
  6. 05/27 bisect: fix multiple leaks in `bisect_next_all()`Patrick Steinhardt, Nov 20, 2024
  7. 06/27 bisect: fix leaking commit list items in `check_merge_base()`Patrick Steinhardt, Nov 20, 2024
  8. 07/27 bisect: fix various cases where we leak commit list itemsPatrick Steinhardt, Nov 20, 2024
  9. Jeff KingNov 25, 2024
  10. Patrick SteinhardtNov 25, 2024
  11. Jeff KingNov 25, 2024
  12. Patrick SteinhardtNov 25, 2024
  13. 08/27 line-log: fix leak when rewriting commit parentsPatrick Steinhardt, Nov 20, 2024
  14. 09/27 strvec: introduce new `strvec_splice()` functionPatrick Steinhardt, Nov 20, 2024
  15. 10/27 git: refactor alias handling to use a `struct strvec`Patrick Steinhardt, Nov 20, 2024
  16. 11/27 git: refactor builtin handling to use a `struct strvec`Patrick Steinhardt, Nov 20, 2024
  17. 12/27 split-index: fix memory leak in `move_cache_to_base_index()`Patrick Steinhardt, Nov 20, 2024
  18. 13/27 builtin/sparse-checkout: fix leaking sanitized patternsPatrick Steinhardt, Nov 20, 2024
  19. 14/27 help: refactor to not use globals for reading configPatrick Steinhardt, Nov 20, 2024
  20. 15/27 help: fix leaking `struct cmdnames`Patrick Steinhardt, Nov 20, 2024
  21. 16/27 help: fix leaking return value from `help_unknown_cmd()`Patrick Steinhardt, Nov 20, 2024
  22. 17/27 builtin/help: fix leaks in `check_git_cmd()`Patrick Steinhardt, Nov 20, 2024
  23. 18/27 builtin/init-db: fix leaking directory pathsPatrick Steinhardt, Nov 20, 2024
  24. 20/27 t/helper: fix leaking commit graph in "read-graph" subcommandPatrick Steinhardt, Nov 20, 2024
  25. 19/27 builtin/branch: fix leaking sorting optionsPatrick Steinhardt, Nov 20, 2024
  26. 21/27 global: drop `UNLEAK()` annotationPatrick Steinhardt, Nov 20, 2024
  27. 22/27 git-compat-util: drop now-unused `UNLEAK()` macroPatrick Steinhardt, Nov 20, 2024
  28. 23/27 t5601: work around leak sanitizer issuePatrick Steinhardt, Nov 20, 2024
  29. 24/27 t: mark some tests as leak freePatrick Steinhardt, Nov 20, 2024
  30. 25/27 t: remove unneeded !SANITIZE_LEAK prerequisitesPatrick Steinhardt, Nov 20, 2024
  31. 26/27 test-lib: unconditionally enable leak checkingPatrick Steinhardt, Nov 20, 2024
  32. 27/27 t: remove TEST_PASSES_SANITIZE_LEAK annotationsPatrick Steinhardt, Nov 20, 2024
  33. Toon ClaesNov 21, 2024

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