Merge branch 'ab/fsck-skiplist'

Update fsck.skipList implementation and documentation.

* ab/fsck-skiplist:
  fsck: support comments & empty lines in skipList
  fsck: use oidset instead of oid_array for skipList
  fsck: use strbuf_getline() to read skiplist file
  fsck: add a performance test for skipList
  fsck: add a performance test
  fsck: document that skipList input must be unabbreviated
  fsck: document and test commented & empty line skipList input
  fsck: document and test sorted skipList input
  fsck tests: add a test for no skipList input
  fsck tests: setup of bogus commit object

1 files changed, 18 insertions, 5 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index fa52b19dff..1546833213 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1567,12 +1567,16 @@ doing the same for `receive.fsck.<msg-id>` and `fetch.fsck.<msg-id>`
 will only cause git to warn.
 
 fsck.skipList::
-	The path to a sorted list of object names (i.e. one SHA-1 per
+	The path to a list of object names (i.e. one unabbreviated SHA-1 per
 	line) that are known to be broken in a non-fatal way and should
-	be ignored. This feature is useful when an established project
-	should be accepted despite early commits containing errors that
-	can be safely ignored such as invalid committer email addresses.
-	Note: corrupt objects cannot be skipped with this setting.
+	be ignored. On versions of Git 2.20 and later comments ('#'), empty
+	lines, and any leading and trailing whitespace is ignored. Everything
+	but a SHA-1 per line will error out on older versions.
++
+This feature is useful when an established project should be accepted
+despite early commits containing errors that can be safely ignored
+such as invalid committer email addresses.  Note: corrupt objects
+cannot be skipped with this setting.
 +
 Like `fsck.<msg-id>` this variable has corresponding
 `receive.fsck.skipList` and `fetch.fsck.skipList` variants.
@@ -1582,6 +1586,15 @@ Unlike variables like `color.ui` and `core.editor` the
 fall back on the `fsck.skipList` configuration if they aren't set. To
 uniformly configure the same fsck settings in different circumstances
 all three of them they must all set to the same values.
++
+Older versions of Git (before 2.20) documented that the object names
+list should be sorted. This was never a requirement, the object names
+could appear in any order, but when reading the list we tracked whether
+the list was sorted for the purposes of an internal binary search
+implementation, which could save itself some work with an already sorted
+list. Unless you had a humongous list there was no reason to go out of
+your way to pre-sort the list. After Git version 2.20 a hash implementation
+is used instead, so there's now no reason to pre-sort the list.
 
 gc.aggressiveDepth::
 	The depth parameter used in the delta compression