[PATCH 0/4] fix a leak with excludes_file

Having ...
	[core]
        	excludesFile = /some/global/path/.gitignore

... this triggers a leak:

	$ GIT_EDITOR=: git rebase -i HEAD
	Successfully rebased and updated detached HEAD.

	=================================================================
	==...==ERROR: LeakSanitizer: detected memory leaks

	Direct leak of 60 byte(s) in 1 object(s) allocated from:
	    #0  ... in realloc 
	    #1  ... in xrealloc wrapper.c:137
	    #2  ... in strbuf_grow strbuf.c:112
	    #3  ... in strbuf_add strbuf.c:311
	    #4  ... in strbuf_addstr strbuf.h:310
	    #5  ... in interpolate_path path.c:771
	    #6  ... in git_config_pathname config.c:1352
	    #7  ... in git_default_core_config config.c:1588
	    #8  ... in git_default_config config.c:1791
	    #9  ... in rebase_config builtin/rebase.c:801
	    #10 ... in configset_iter config.c:2161
	    #11 ... in repo_config config.c:2540
	    #12 ... in git_config config.c:2663
	    #13 ... in cmd_rebase builtin/rebase.c:1187
	    #14 ... in run_builtin git.c:469
	    #15 ... in handle_builtin git.c:724
	    #16 ... in run_argv git.c:788
	    #17 ... in cmd_main git.c:923
	    #18 ... in main common-main.c:62

It happens because we parse twice the configuration: 

	$ GIT_EDITOR=: gdb --ex "break git_config" --ex "run" --args git rebase -i HEAD
	(gdb) bt
	#0  git_config () at config.c:2663
	#1  ... in cmd_rebase () at builtin/rebase.c:1187
	#2  ... in run_builtin () at git.c:469
	#3  ... in handle_builtin () at git.c:724
	#4  ... in run_argv () at git.c:788
	#5  ... in cmd_main () at git.c:923
	#6  ... in main () at common-main.c:62
	(gdb) c
	(gdb) bt
	#0  git_config () at config.c:2663
	#1  ... in sequencer_init_config () at sequencer.c:291
	#2  ... in get_replay_opts () at builtin/rebase.c:161
	#3  ... in do_interactive_rebase () at builtin/rebase.c:271
	#4  ... in run_sequencer_rebase () at builtin/rebase.c:339
	#5  ... in run_specific_rebase () at builtin/rebase.c:705
	#6  ... in cmd_rebase () at builtin/rebase.c:1830
	#7  ... in run_builtin () at git.c:469
	#8  ... in handle_builtin () at git.c:724
	#9  ... in run_argv () at git.c:788
	#10 ... in cmd_main () at git.c:923
	#11 ... in main () at common-main.c:62

We call twice to git_config(): first to get the main git-branch(1) options, and second to get the ones related to the sequencer.

Due to how git_config() works the global configuration is parsed twice, therefore if core.excludesFile is set, it will be allocated twice.

A free() before the git_config_pathname() can be a simpler fix, but I think this series offers a better approach, perhaps applicable to other potential similar leaks.

Rubén Justo (4):
  path.c: introduce strbuf_interpolate_path
  config.c: introduce git_config_strbuf_pathname
  environment.c: convert excludes_file to struct strbuf
  t7300: mark as leak-free

 config.c         | 12 +++++++++++-
 config.h         |  2 ++
 dir.c            | 13 +++++++++----
 environment.c    |  2 +-
 environment.h    |  2 +-
 path.c           | 20 ++++++++++++++------
 path.h           |  1 +
 t/t7300-clean.sh |  1 +
 8 files changed, 40 insertions(+), 13 deletions(-)