@matheusbsbs / matheus-bagliano / commits / a77554ea09

diff-tree: fix crash when used with --remerge-diff

When using "git-diff-tree" to get the tree diff for merge commits with the diff format set to `remerge`, a bug is triggered as shown below: $ git diff-tree -r --remerge-diff 363337e6eb 363337e6eb812d0c0d785ed4261544f35559ff8b BUG: log-tree.c:1006: did a remerge diff without remerge_objdir?!? This bug is reported by `log-tree.c:do_remerge_diff`, where a bug check added in commit 7b90ab467a (log: clean unneeded objects during log --remerge-diff, 2022-02-02) detects the absence of `remerge_objdir` when attempting to clean up temporary objects generated during the remerge process. After some further digging, I find that the remerge-related diff options were introduced in db757e8b8d (show, log: provide a --remerge-diff capability, 2022-02-02), which also affect the setup of `rev_info` for "git-diff-tree", but were not accounted for in the original implementation (inferred from the commit message). Elijah Newren, the author of the remerge diff feature, notes that other callers of `log-tree.c:log_tree_commit` (the only caller of `log-tree.c:do_remerge_diff`) also exist, but: `builtin/am.c`: manually sets all flags; remerge_diff is not among them `sequencer.c`: manually sets all flags; remerge_diff is not among them so `builtin/diff-tree.c` really is the only caller that was overlooked when remerge-diff functionality was added. This commit resolves the crash by adding `remerge_objdir` setup logic to `builtin/diff-tree.c`, mirroring `builtin/log.c:cmd_log_walk_no_free`. It also includes the necessary cleanup for `remerge_objdir`. Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Xing Xin <xingxin.xx@bytedance.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Xing Xin committed Aug 9, 2024 at 07:24 UTC a77554ea0972e4ec3518fb8fb0b2582c76cf3105
2 files changed +48
builtin/diff-tree.c
+13
@@ -9,6 +9,7 @@
9 #include "read-cache-ll.h"
10 #include "repository.h"
11 #include "revision.h"
12 +#include "tmp-objdir.h"
13 #include "tree.h"
14
15 static struct rev_info log_tree_opt;
@@ -167,6 +168,13 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
168
169 opt->diffopt.rotate_to_strict = 1;
170
171 + if (opt->remerge_diff) {
172 + opt->remerge_objdir = tmp_objdir_create("remerge-diff");
173 + if (!opt->remerge_objdir)
174 + die(_("unable to create temporary object directory"));
175 + tmp_objdir_replace_primary_odb(opt->remerge_objdir, 1);
176 + }
177 +
178 /*
179 * NOTE! We expect "a..b" to expand to "^a b" but it is
180 * perfectly valid for revision range parser to yield "b ^a",
@@ -231,5 +239,10 @@ int cmd_diff_tree(int argc, const char **argv, const char *prefix)
239 diff_free(&opt->diffopt);
240 }
241
242 + if (opt->remerge_diff) {
243 + tmp_objdir_destroy(opt->remerge_objdir);
244 + opt->remerge_objdir = NULL;
245 + }
246 +
247 return diff_result_code(&opt->diffopt);
248 }
t/t4069-remerge-diff.sh
+35
@@ -110,6 +110,41 @@ test_expect_success 'can filter out additional headers with pickaxe' '
110 test_must_be_empty actual
111 '
112
113 +test_expect_success 'remerge-diff also works for git-diff-tree' '
114 + # With a clean merge
115 + git diff-tree -r -p --remerge-diff --no-commit-id bc_resolution >actual &&
116 + test_must_be_empty actual &&
117 +
118 + # With both a resolved conflict and an unrelated change
119 + cat <<-EOF >tmp &&
120 + diff --git a/numbers b/numbers
121 + remerge CONFLICT (content): Merge conflict in numbers
122 + index a1fb731..6875544 100644
123 + --- a/numbers
124 + +++ b/numbers
125 + @@ -1,13 +1,9 @@
126 + 1
127 + 2
128 + -<<<<<<< b0ed5cb (change_a)
129 + -three
130 + -=======
131 + -tres
132 + ->>>>>>> 6cd3f82 (change_b)
133 + +drei
134 + 4
135 + 5
136 + 6
137 + 7
138 + -eight
139 + +acht
140 + 9
141 + EOF
142 + sed -e "s/[0-9a-f]\{7,\}/HASH/g" tmp >expect &&
143 + git diff-tree -r -p --remerge-diff --no-commit-id ab_resolution >tmp &&
144 + sed -e "s/[0-9a-f]\{7,\}/HASH/g" tmp >actual &&
145 + test_cmp expect actual
146 +'
147 +
148 test_expect_success 'setup non-content conflicts' '
149 git switch --orphan base &&
150