revisions API: have release_revisions() release "mailmap"

Extend the the release_revisions() function so that it frees the
"mailmap" in the "struct rev_info".

The log family of functions now calls the clear_mailmap() function
added in fa8afd18e5a (revisions API: provide and use a
release_revisions(), 2021-09-19), allowing us to whitelist some tests
with "TEST_PASSES_SANITIZE_LEAK=true".

Unfortunately having a pointer to a mailmap in "struct rev_info"
instead of an embedded member that we "own" get a bit messy, as can be
seen in the change to builtin/commit.c.

When we free() this data we won't be able to tell apart a pointer to a
"mailmap" on the heap from one on the stack. As seen in
ea57bc0d41b (log: add --use-mailmap option, 2013-01-05) the "log"
family allocates it on the heap, but in the find_author_by_nickname()
code added in ea16794e430 (commit: search author pattern against
mailmap, 2013-08-23) we allocated it on the stack instead.

Ideally we'd simply change that member to a "struct string_list
mailmap" and never free() the "mailmap" itself, but that would be a
much larger change to the revisions API.

We have code that needs to hand an existing "mailmap" to a "struct
rev_info", while we could change all of that, let's not go there
now.

The complexity isn't in the ownership of the "mailmap" per-se, but
that various things assume a "rev_info.mailmap == NULL" means "doesn't
want mailmap", if we changed that to an init'd "struct string_list
we'd need to carefully refactor things to change those assumptions.

Let's instead always free() it, and simply declare that if you add
such a "mailmap" it must be allocated on the heap. Any modern libc
will correctly panic if we free() a stack variable, so this should be
safe going forward.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

5 files changed, 5 insertions, 0 deletions

diff --git a/t/t0056-git-C.sh b/t/t0056-git-C.sh
index 2630e75..752aa8c 100755
--- a/t/t0056-git-C.sh
+++ b/t/t0056-git-C.sh
@@ -2,6 +2,7 @@
 
 test_description='"-C <path>" option and its effects on other path-related options'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success '"git -C <path>" runs git from the directory <path>' '
diff --git a/t/t3302-notes-index-expensive.sh b/t/t3302-notes-index-expensive.sh
index bb5fea0..d0c4d38 100755
--- a/t/t3302-notes-index-expensive.sh
+++ b/t/t3302-notes-index-expensive.sh
@@ -8,6 +8,7 @@ test_description='Test commit notes index (expensive!)'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 create_repo () {
diff --git a/t/t4055-diff-context.sh b/t/t4055-diff-context.sh
index 741e080..73048d0 100755
--- a/t/t4055-diff-context.sh
+++ b/t/t4055-diff-context.sh
@@ -5,6 +5,7 @@
 
 test_description='diff.context configuration'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t4066-diff-emit-delay.sh b/t/t4066-diff-emit-delay.sh
index a1de63b..0ecb391 100755
--- a/t/t4066-diff-emit-delay.sh
+++ b/t/t4066-diff-emit-delay.sh
@@ -4,6 +4,7 @@ test_description='test combined/stat/moved interaction'
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # This test covers a weird 3-way interaction between "--cc -p", which will run
diff --git a/t/t7008-filter-branch-null-sha1.sh b/t/t7008-filter-branch-null-sha1.sh
index 9ba9f24..93fbc92 100755
--- a/t/t7008-filter-branch-null-sha1.sh
+++ b/t/t7008-filter-branch-null-sha1.sh
@@ -1,6 +1,7 @@
 #!/bin/sh
 
 test_description='filter-branch removal of trees with null sha1'
+
 . ./test-lib.sh
 
 test_expect_success 'setup: base commits' '