Re: [PATCHv4] git apply: option to ignore whitespace differences

diff --git a/builtin-apply.c b/builtin-apply.c
index 39dc96a..7ec5b8b 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c

@@ -1773,12 +1866,57 @@ static int match_fragment(struct image *img,
 	    !memcmp(img->buf + try, preimage->buf, preimage->len))
 		return 1;
 
+	/*
+	 * No exact match. If we are ignoring whitespace, run a line-by-line
+	 * fuzzy matching. We collect all the line length information because
+	 * we need it to adjust whitespace if we match.
+	 */
+	if (ws_ignore_action == ignore_ws_change) {
+		size_t imgoff = 0;
+		size_t preoff = 0;
+		size_t postlen = postimage->len;
+		size_t imglen[preimage->nr];
+		for (i = 0; i < preimage->nr; i++) {
+			imglen[i] = img->line[try_lno+i].len;
+			size_t prelen = preimage->line[i].len;
+			if (!fuzzy_matchlines(
+				img->buf + try + imgoff, imglen[i],
+				preimage->buf + preoff, prelen))
+				return 0;
+			if (preimage->line[i].flag & LINE_COMMON)
+				postlen += imglen[i] - prelen;
+			imgoff += imglen[i];
+			preoff += prelen;
+		}
+
+		/*
+		 * Ok, the preimage matches with whitespace fuzz. Update it and
+		 * the common postimage lines to use the same whitespace as the
+		 * target. imgoff now holds the true length of the target that
+		 * matches the preimage, and we need to update the line lengths
+		 * of the preimage to match the target ones.
+		 */
+		fixed_buf = xmalloc(imgoff);
+		memcpy(fixed_buf, img->buf + try, imgoff);
+		for (i = 0; i < preimage->nr; i++)
+			preimage->line[i].len = imglen[i];
+
+		/*
+		 * Update the preimage buffer and the postimage context lines.
+		 */
+		update_pre_post_images(preimage, postimage,
+				fixed_buf, imgoff, postlen);
+		return 1;
+	}
+

Why do you need imglen[] vla here?  IOW, can't the above be simply like
this?

diff --git a/builtin-apply.c b/builtin-apply.c
index ae11b41..c8372a0 100644
--- a/builtin-apply.c
+++ b/builtin-apply.c

@@ -1874,20 +1874,18 @@ static int match_fragment(struct image *img,

       if (ws_ignore_action == ignore_ws_change) {
               size_t imgoff = 0;
               size_t preoff = 0;
               size_t postlen = postimage->len;
-               size_t imglen[preimage->nr];
               for (i = 0; i < preimage->nr; i++) {
                       size_t prelen = preimage->line[i].len;
+                       size_t imglen = img->line[try_lno+i].len;

-                       imglen[i] = img->line[try_lno+i].len;
-                       if (!fuzzy_matchlines(
-                               img->buf + try + imgoff, imglen[i],
-                               preimage->buf + preoff, prelen))
+                       if (!fuzzy_matchlines(img->buf + try + imgoff, imglen,
+                                             preimage->buf + preoff, prelen))
                               return 0;
                       if (preimage->line[i].flag & LINE_COMMON)
-                               postlen += imglen[i] - prelen;
-                       imgoff += imglen[i];
+                               postlen += imglen - prelen;
+                       imgoff += imglen;
                       preoff += prelen;
               }

               /*

@@ -1899,9 +1897,9 @@ static int match_fragment(struct image *img,

                */
               fixed_buf = xmalloc(imgoff);
               memcpy(fixed_buf, img->buf + try, imgoff);
               for (i = 0; i < preimage->nr; i++)
-                       preimage->line[i].len = imglen[i];
+                       preimage->line[i].len = img->line[try_lno+i].len;