Detect concatenated git-style patches by tracking what's in the output queue

* src/patch.c (main): Instead of looking at the SHA hashes to detect
concatenated git-style patches, detect when a file to write to is already in
the output queue.
* tests/concat-git-diff: Add create/delete tests.

2 files changed, 46 insertions, 26 deletions

diff --git a/src/patch.c b/src/patch.c
index 9dc71f2..febfd42 100644
--- a/src/patch.c
+++ b/src/patch.c
@@ -237,37 +237,47 @@ main (int argc, char **argv)
 	    outname = pch_name (! strcmp (inname, pch_name (OLD)));
 	  else
 	    outname = inname;
-
-	  if (! get_input_file (inname, outname, file_type))
-	    {
-	      skip_rest_of_patch = true;
-	      somefailed = true;
-	    }
 	}
 
-      if (pch_git_diff () && ! skip_rest_of_patch && ! inerrno)
+      if (pch_git_diff () && ! skip_rest_of_patch)
 	{
+	  struct stat outstat;
+	  int outerrno = 0;
+
 	  /* Try to recognize concatenated git diffs based on the SHA1 hashes
 	     in the headers.  Will not always succeed for patches that rename
 	     or copy files.  */
 
-	  char const *previous_sha1 = lookup_sha1 (&instat);
-
-	  if (previous_sha1)
+	  if (! strcmp (inname, outname))
 	    {
-	      char const *sha1 = pch_sha1 (reverse);
+	      if (inerrno == -1)
+		inerrno = lstat (inname, &instat) ? errno : 0;
+	      outstat = instat;
+	      outerrno = inerrno;
+	    }
+	  else
+	    outerrno = lstat (outname, &outstat) ? errno : 0;
 
-	      for (; *previous_sha1 && *sha1; previous_sha1++, sha1++)
-		if (*previous_sha1 != *sha1)
-		  break;
-	      if (*previous_sha1 && *sha1)
+	  if (! outerrno)
+	    {
+	      if (has_queued_output (&outstat))
 		{
-		  output_files (&instat);
-		  update_sha1 (&instat, pch_sha1 (reverse));
+		  output_files (&outstat);
+		  outerrno = lstat (outname, &outstat) ? errno : 0;
+		  inerrno = -1;
 		}
+	      if (! outerrno)
+		set_queued_output (&outstat, true);
+	    }
+	}
+
+      if (! skip_rest_of_patch)
+	{
+	  if (! get_input_file (inname, outname, file_type))
+	    {
+	      skip_rest_of_patch = true;
+	      somefailed = true;
 	    }
-	  else
-	    update_sha1 (&instat, pch_sha1 (reverse));
 	}
 
       if (read_only_behavior != RO_IGNORE
diff --git a/tests/concat-git-diff b/tests/concat-git-diff
index 52d3004..927eb5a 100644
--- a/tests/concat-git-diff
+++ b/tests/concat-git-diff
@@ -12,20 +12,29 @@ use_tmpdir
 
 # ==============================================================
 
+echo zero > f
+
 cat > concatenated.diff <<EOF
 diff --git a/f b/f
-new file mode 100644
-index 0000000..5626abf
---- /dev/null
+index 26af6a8..5626abf 100644
+--- a/f
 +++ b/f
-@@ -0,0 +1 @@
+@@ -1 +1 @@
+-zero
 +one
 diff --git a/f b/f
-index 5626abf..f719efd 100644
+deleted file mode 100644
+index 5626abf..0000000
 --- a/f
-+++ b/f
-@@ -1 +1 @@
++++ /dev/null
+@@ -1 +0,0 @@
 -one
+diff --git a/f b/f
+new file mode 100644
+index 0000000..f719efd
+--- /dev/null
++++ b/f
+@@ -0,0 +1 @@
 +two
 diff --git a/f b/f
 index f719efd..2bdf67a 100644
@@ -40,6 +49,7 @@ check 'patch -p1 < concatenated.diff || echo "Status: $?"' <<EOF
 patching file f
 patching file f
 patching file f
+patching file f
 EOF
 
 check 'cat f' <<EOF