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Bug 331472

Summary:	type change and rename wrong patch order
Product:	[Technology] JGit	Reporter:	Shawn Pearce <sop>
Component:	JGit	Assignee:	Project Inbox <jgit.core-inbox>
Status:	RESOLVED WONTFIX	QA Contact:
Severity:	major
Priority:	P3
Version:	unspecified
Target Milestone:	---
Hardware:	All
OS:	All
Whiteboard:

Description Shawn Pearce

2010-11-30 15:30:49 EST

C Git and JGit differ about how a patch should appear when renaming a file and also creating a symlink at the old name location.

  $ git diff -M HEAD^ HEAD
  diff --git a/a b/a
  deleted file mode 100644
  index ce01362..0000000
  --- a/a
  +++ /dev/null
  @@ -1 +0,0 @@
  -hello
  diff --git a/a b/a
  new file mode 120000
  index 0000000..63d8dbd
  --- /dev/null
  +++ b/a
  @@ -0,0 +1 @@
  +b
  \ No newline at end of file
  diff --git a/b b/b
  new file mode 100644
  index 0000000..ce01362
  --- /dev/null
  +++ b/b
  @@ -0,0 +1 @@
  +hello

JGit correctly identifies the rename, but fails because the rename occurs after the symlink creation.  The rename needs to come first to ensure the old name is available for the symlink to create under:

  $ ../jgit/jgit diff -M HEAD^ HEAD
  diff --git a/a b/a
  new file mode 120000
  index 0000000..63d8dbd
  --- /dev/null
  +++ b/a
  @@ -0,0 +1 @@
  +b
  \ No newline at end of file
  diff --git a/a b/b
  similarity index 100%
  rename from a
  rename to b

Comment 1 Shawn Pearce

2010-12-03 16:42:49 EST

Spoke to Junio C Hamano about this, turns out the patch order is fine.  git apply applies patches relative to the old tree, so actual order between files within a patch is irrelevant.  This permits concatenating two patches together, because that's what Linus Torvalds wanted to be able to do.