crlf: pass-through mixed EOL buffers from LF->CRLFcmn/mixed-eol-passthrough

When checking out files, we're performing conversion into the user's
native line endings, but we only want to do it for files which have
consistent line endings. Refuse to perform the conversion for mixed-EOL
files.

The CRLF->LF filter is left as-is, as that conversion is considered to be
normalization by git and should force a conversion of the line endings.

1 files changed, 9 insertions, 5 deletions

diff --git a/src/buf_text.c b/src/buf_text.c
index 631feb3f8..8d2b141b2 100644
--- a/src/buf_text.c
+++ b/src/buf_text.c
@@ -123,9 +123,13 @@ int git_buf_text_lf_to_crlf(git_buf *tgt, const git_buf *src)
 
 	for (; next; scan = next + 1, next = memchr(scan, '\n', end - scan)) {
 		size_t copylen = next - scan;
-		/* don't convert existing \r\n to \r\r\n */
-		size_t extralen = (next > start && next[-1] == '\r') ? 1 : 2;
-		size_t needsize = tgt->size + copylen + extralen + 1;
+		size_t needsize = tgt->size + copylen + 2 + 1;
+
+		/* if we find mixed line endings, bail */
+		if (next > start && next[-1] == '\r') {
+			git_buf_free(tgt);
+			return GIT_PASSTHROUGH;
+		}
 
 		if (tgt->asize < needsize && git_buf_grow(tgt, needsize) < 0)
 			return -1;
@@ -134,8 +138,8 @@ int git_buf_text_lf_to_crlf(git_buf *tgt, const git_buf *src)
 			memcpy(tgt->ptr + tgt->size, scan, copylen);
 			tgt->size += copylen;
 		}
-		if (extralen == 2)
-			tgt->ptr[tgt->size++] = '\r';
+
+		tgt->ptr[tgt->size++] = '\r';
 		tgt->ptr[tgt->size++] = '\n';
 	}