From: Andreas Gruenbacher <agruen@suse.de>
Subject: diff3-style merges: merge rejects

With the --merge-all option, hunks which do not apply and which would
end up in a *.rej file will also get added to output files. They will
be bracketed like this:

	<<<<<<<
	old lines from patch
	|||||||
	new lines from patch
	>>>>>>>

With this change, all pieces of a patch can be applied, and all the
resulting merge conflicts can be fixed in the patched files instead
of looking at the reject files.

Signed-off-by: Andreas Gruenbacher <agruen@suse.de>

---
 patch.c |   40 +++++++++++++++++++++++++++++++---------
 1 file changed, 31 insertions(+), 9 deletions(-)

Index: b/patch.c
===================================================================
--- a/patch.c
+++ b/patch.c
@@ -79,7 +79,7 @@ static void reinitialize_almost_everythi
 static void remove_if_needed (char const *, int volatile *);
 static void usage (FILE *, int) __attribute__((noreturn));
 
-enum mergetype { SHOW_ALL = 1, SHOW_FUZZ = 2 };
+enum mergetype { SHOW_ALL = 1, SHOW_FUZZ = 2, MERGE_REJECTS = 4 };
 static enum mergetype mergetype;
 
 static bool make_backups;
@@ -299,7 +299,18 @@ main (int argc, char **argv)
 
 		goto skip_hunk;
 	    } else if (!where) {
-		goto skip_hunk;
+		if (mergetype & MERGE_REJECTS) {
+		    LINENUM guess = pch_first () + last_offset;
+
+		    if (merge_hunk(&outstate, guess, -1)) {
+			merged++;
+			mismatch = 1;
+		    } else {
+			/* FIXME: guess harder! */
+			goto skip_hunk;
+		    }
+		} else
+		    goto skip_hunk;
 	    } else {
 		if ((mergetype & SHOW_ALL) ||
 		    (fuzz && (mergetype & SHOW_FUZZ))) {
@@ -316,10 +327,16 @@ main (int argc, char **argv)
 	    
 	    if (verbosity == VERBOSE
 		|| (verbosity != SILENT && (fuzz || last_offset))) {
-		say ("Hunk #%d succeeded at %s", hunk,
-		     format_linenum (numbuf, newwhere));
-		if (fuzz)
-		  say (" with fuzz %s", format_linenum (numbuf, fuzz));
+		    if (fuzz > mymaxfuzz) {
+			say ("Hunk #%d merged at %s with errors", hunk,
+			     format_linenum (numbuf, newwhere));
+		        somefailed = true;
+		    } else {
+			say ("Hunk #%d succeeded at %s", hunk,
+			     format_linenum (numbuf, newwhere));
+			if (fuzz)
+			  say (" with fuzz %s", format_linenum (numbuf, fuzz));
+		    }
 		if (last_offset)
 		  say (" (offset %s line%s)",
 		       format_linenum (numbuf, last_offset),
@@ -521,7 +538,7 @@ reinitialize_almost_everything (void)
     skip_rest_of_patch = false;
 }
 
-static char const shortopts[] = "bB:cd:D:eEfF:g:i:lnNo:p:r:RstTuvV:x:Y:z:Z";
+static char const shortopts[] = "bB:cd:D:eEfF:g:i:lMnNo:p:r:RstTuvV:x:Y:z:Z";
 static struct option const longopts[] =
 {
   {"backup", no_argument, NULL, 'b'},
@@ -591,7 +608,7 @@ static char const *const option_help[] =
 "  -r FILE  --reject-file=FILE  Output rejects to FILE.",
 "",
 "  -D NAME  --ifdef=NAME  Make merged if-then-else output using NAME.",
-"  --merge={fuzz,all}  Produce a diff3-style merge.",
+"  --merge={rejects,fuzz,all}  Produce a diff3-style merge.",
 "  -E  --remove-empty-files  Remove output files that are empty after patching.",
 "",
 "  -Z  --set-utc  Set times of patched files, assuming diff uses UTC (GMT).",
@@ -730,6 +747,9 @@ get_some_switches (void)
 	    case 'l':
 		canonicalize = true;
 		break;
+	    case 'M':
+	    	mergetype |= MERGE_REJECTS;
+		break;
 	    case 'n':
 		diff_type = NORMAL_DIFF;
 		break;
@@ -835,7 +855,9 @@ get_some_switches (void)
 		    char *tok = strtok(optarg, ",");
 
 		    do {
-			if (!strcmp(tok, "fuzz"))
+			if (!strcmp(tok, "rejects"))
+			    mergetype |= MERGE_REJECTS;
+			else if (!strcmp(tok, "fuzz"))
 			    mergetype |= SHOW_FUZZ;
 			else if (!strcmp(tok, "all"))
 			    mergetype |= SHOW_ALL;