From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 24 Sep 2018 17:30:46 +0000 (-0700)
Subject: Merge branch 'jk/reopen-tempfile-truncate'
X-Git-Tag: v2.20.0-rc0~220
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/48a81ed29795da3e4cc40d4e5ea535878e4f2d9f?ds=inline;hp=-c

Merge branch 'jk/reopen-tempfile-truncate'

Fix for a long-standing bug that leaves the index file corrupt when
it shrinks during a partial commit.

* jk/reopen-tempfile-truncate:
reopen_tempfile(): truncate opened file
---

48a81ed29795da3e4cc40d4e5ea535878e4f2d9f
diff --combined t/t0090-cache-tree.sh
index 7de40141ca,596e269394..94fcb4a78e
--- a/t/t0090-cache-tree.sh
+++ b/t/t0090-cache-tree.sh
@@@ -156,11 -156,29 +156,29 @@@ test_expect_success PERL 'commit --inte
  		return 44;
  	}
  	EOT
 -	(echo p; echo 1; echo; echo s; echo n; echo y; echo q) |
 +	test_write_lines p 1 "" s n y q |
  	git commit --interactive -m foo &&
  	test_cache_tree
  '
  
+ test_expect_success PERL 'commit -p with shrinking cache-tree' '
+ 	mkdir -p deep/subdir &&
+ 	echo content >deep/subdir/file &&
+ 	git add deep &&
+ 	git commit -m add &&
+ 	git rm -r deep &&
+ 
+ 	before=$(wc -c <.git/index) &&
+ 	git commit -m delete -p &&
+ 	after=$(wc -c <.git/index) &&
+ 
+ 	# double check that the index shrank
+ 	test $before -gt $after &&
+ 
+ 	# and that our index was not corrupted
+ 	git fsck
+ '
+ 
  test_expect_success 'commit in child dir has cache-tree' '
  	mkdir dir &&
  	>dir/child.t &&
@@@ -239,7 -257,7 +257,7 @@@ test_expect_success 'no phantom error w
  	>newdir/one &&
  	git add newdir/one &&
  	git checkout 2>errors &&
 -	! test -s errors
 +	test_must_be_empty errors
  '
  
  test_expect_success 'switching trees does not invalidate shared index' '
diff --combined tempfile.h
index 36434eb6fa,b1b085540b..61d8dc4d1b
--- a/tempfile.h
+++ b/tempfile.h
@@@ -2,7 -2,6 +2,7 @@@
  #define TEMPFILE_H
  
  #include "list.h"
 +#include "strbuf.h"
  
  /*
   * Handle temporary files.
@@@ -236,8 -235,8 +236,8 @@@ extern int close_tempfile_gently(struc
   *   it (and nobody else) to inspect or even modify the file's
   *   contents.
   *
-  * * `reopen_tempfile()` to reopen the temporary file. Make further
-  *   updates to the contents.
+  * * `reopen_tempfile()` to reopen the temporary file, truncating the existing
+  *   contents. Write out the new contents.
   *
   * * `rename_tempfile()` to move the file to its permanent location.
   */