revert(3p/git): Revert merge of git upstream at v2.26.2 r/852

This causes cgit to serve error pages, which is undesirable.

This reverts commit 5229c9b232de5bfa959ad6ebbb4c8192ac513352, reversing
changes made to f2b211131f2347342dde63975b09cf603149f1a3.

2 files changed, 44 insertions, 72 deletions

diff --git a/third_party/git/xdiff/xdiffi.c b/third_party/git/xdiff/xdiffi.c
index bd035139f954..1f1f4a3c7808 100644
--- a/third_party/git/xdiff/xdiffi.c
+++ b/third_party/git/xdiff/xdiffi.c
@@ -38,9 +38,9 @@ typedef struct s_xdpsplit {
  * Basically considers a "box" (off1, off2, lim1, lim2) and scan from both
  * the forward diagonal starting from (off1, off2) and the backward diagonal
  * starting from (lim1, lim2). If the K values on the same diagonal crosses
- * returns the furthest point of reach. We might encounter expensive edge cases
- * using this algorithm, so a little bit of heuristic is needed to cut the
- * search and to return a suboptimal point.
+ * returns the furthest point of reach. We might end up having to expensive
+ * cases using this algorithm is full, so a little bit of heuristic is needed
+ * to cut the search and to return a suboptimal point.
  */
 static long xdl_split(unsigned long const *ha1, long off1, long lim1,
 		      unsigned long const *ha2, long off2, long lim2,
@@ -63,13 +63,11 @@ static long xdl_split(unsigned long const *ha1, long off1, long lim1,
 		int got_snake = 0;
 
 		/*
-		 * We need to extend the diagonal "domain" by one. If the next
+		 * We need to extent the diagonal "domain" by one. If the next
 		 * values exits the box boundaries we need to change it in the
-		 * opposite direction because (max - min) must be a power of
-		 * two.
-		 *
+		 * opposite direction because (max - min) must be a power of two.
 		 * Also we initialize the external K value to -1 so that we can
-		 * avoid extra conditions in the check inside the core loop.
+		 * avoid extra conditions check inside the core loop.
 		 */
 		if (fmin > dmin)
 			kvdf[--fmin - 1] = -1;
@@ -100,13 +98,11 @@ static long xdl_split(unsigned long const *ha1, long off1, long lim1,
 		}
 
 		/*
-		 * We need to extend the diagonal "domain" by one. If the next
+		 * We need to extent the diagonal "domain" by one. If the next
 		 * values exits the box boundaries we need to change it in the
-		 * opposite direction because (max - min) must be a power of
-		 * two.
-		 *
+		 * opposite direction because (max - min) must be a power of two.
 		 * Also we initialize the external K value to -1 so that we can
-		 * avoid extra conditions in the check inside the core loop.
+		 * avoid extra conditions check inside the core loop.
 		 */
 		if (bmin > dmin)
 			kvdb[--bmin - 1] = XDL_LINE_MAX;
@@ -142,7 +138,7 @@ static long xdl_split(unsigned long const *ha1, long off1, long lim1,
 		/*
 		 * If the edit cost is above the heuristic trigger and if
 		 * we got a good snake, we sample current diagonals to see
-		 * if some of them have reached an "interesting" path. Our
+		 * if some of the, have reached an "interesting" path. Our
 		 * measure is a function of the distance from the diagonal
 		 * corner (i1 + i2) penalized with the distance from the
 		 * mid diagonal itself. If this value is above the current
@@ -200,9 +196,8 @@ static long xdl_split(unsigned long const *ha1, long off1, long lim1,
 		}
 
 		/*
-		 * Enough is enough. We spent too much time here and now we
-		 * collect the furthest reaching path using the (i1 + i2)
-		 * measure.
+		 * Enough is enough. We spent too much time here and now we collect
+		 * the furthest reaching path using the (i1 + i2) measure.
 		 */
 		if (ec >= xenv->mxcost) {
 			long fbest, fbest1, bbest, bbest1;
@@ -249,9 +244,9 @@ static long xdl_split(unsigned long const *ha1, long off1, long lim1,
 
 
 /*
- * Rule: "Divide et Impera" (divide & conquer). Recursively split the box in
- * sub-boxes by calling the box splitting function. Note that the real job
- * (marking changed lines) is done in the two boundary reaching checks.
+ * Rule: "Divide et Impera". Recursively split the box in sub-boxes by calling
+ * the box splitting function. Note that the real job (marking changed lines)
+ * is done in the two boundary reaching checks.
  */
 int xdl_recs_cmp(diffdata_t *dd1, long off1, long lim1,
 		 diffdata_t *dd2, long off2, long lim2,
@@ -328,9 +323,7 @@ int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 	}
 
 	/*
-	 * Allocate and setup K vectors to be used by the differential
-	 * algorithm.
-	 *
+	 * Allocate and setup K vectors to be used by the differential algorithm.
 	 * One is to store the forward path and one to store the backward path.
 	 */
 	ndiags = xe->xdf1.nreff + xe->xdf2.nreff + 3;
@@ -401,8 +394,8 @@ static int recs_match(xrecord_t *rec1, xrecord_t *rec2, long flags)
 /*
  * If a line is indented more than this, get_indent() just returns this value.
  * This avoids having to do absurd amounts of work for data that are not
- * human-readable text, and also ensures that the output of get_indent fits
- * within an int.
+ * human-readable text, and also ensures that the output of get_indent fits within
+ * an int.
  */
 #define MAX_INDENT 200
 
@@ -436,9 +429,9 @@ static int get_indent(xrecord_t *rec)
 }
 
 /*
- * If more than this number of consecutive blank rows are found, just return
- * this value. This avoids requiring O(N^2) work for pathological cases, and
- * also ensures that the output of score_split fits in an int.
+ * If more than this number of consecutive blank rows are found, just return this
+ * value. This avoids requiring O(N^2) work for pathological cases, and also
+ * ensures that the output of score_split fits in an int.
  */
 #define MAX_BLANKS 20
 
@@ -450,8 +443,8 @@ struct split_measurement {
 	int end_of_file;
 
 	/*
-	 * How much is the line immediately following the split indented (or -1
-	 * if the line is blank):
+	 * How much is the line immediately following the split indented (or -1 if
+	 * the line is blank):
 	 */
 	int indent;
 
@@ -461,8 +454,8 @@ struct split_measurement {
 	int pre_blank;
 
 	/*
-	 * How much is the nearest non-blank line above the split indented (or
-	 * -1 if there is no such line)?
+	 * How much is the nearest non-blank line above the split indented (or -1
+	 * if there is no such line)?
 	 */
 	int pre_indent;
 
@@ -588,13 +581,13 @@ static void measure_split(const xdfile_t *xdf, long split,
 
 /*
  * Compute a badness score for the hypothetical split whose measurements are
- * stored in m. The weight factors were determined empirically using the tools
- * and corpus described in
+ * stored in m. The weight factors were determined empirically using the tools and
+ * corpus described in
  *
  *     https://github.com/mhagger/diff-slider-tools
  *
- * Also see that project if you want to improve the weights based on, for
- * example, a larger or more diverse corpus.
+ * Also see that project if you want to improve the weights based on, for example,
+ * a larger or more diverse corpus.
  */
 static void score_add_split(const struct split_measurement *m, struct split_score *s)
 {
@@ -816,16 +809,13 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
 	group_init(xdfo, &go);
 
 	while (1) {
-		/*
-		 * If the group is empty in the to-be-compacted file, skip it:
-		 */
+		/* If the group is empty in the to-be-compacted file, skip it: */
 		if (g.end == g.start)
 			goto next;
 
 		/*
 		 * Now shift the change up and then down as far as possible in
-		 * each direction. If it bumps into any other changes, merge
-		 * them.
+		 * each direction. If it bumps into any other changes, merge them.
 		 */
 		do {
 			groupsize = g.end - g.start;
@@ -868,17 +858,17 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
 		 * If the group can be shifted, then we can possibly use this
 		 * freedom to produce a more intuitive diff.
 		 *
-		 * The group is currently shifted as far down as possible, so
-		 * the heuristics below only have to handle upwards shifts.
+		 * The group is currently shifted as far down as possible, so the
+		 * heuristics below only have to handle upwards shifts.
 		 */
 
 		if (g.end == earliest_end) {
 			/* no shifting was possible */
 		} else if (end_matching_other != -1) {
 			/*
-			 * Move the possibly merged group of changes back to
-			 * line up with the last group of changes from the
-			 * other file that it can align with.
+			 * Move the possibly merged group of changes back to line
+			 * up with the last group of changes from the other file
+			 * that it can align with.
 			 */
 			while (go.end == go.start) {
 				if (group_slide_up(xdf, &g, flags))
@@ -889,15 +879,14 @@ int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
 		} else if (flags & XDF_INDENT_HEURISTIC) {
 			/*
 			 * Indent heuristic: a group of pure add/delete lines
-			 * implies two splits, one between the end of the
-			 * "before" context and the start of the group, and
-			 * another between the end of the group and the
-			 * beginning of the "after" context. Some splits are
-			 * aesthetically better and some are worse. We compute
-			 * a badness "score" for each split, and add the scores
-			 * for the two splits to define a "score" for each
-			 * position that the group can be shifted to. Then we
-			 * pick the shift with the lowest score.
+			 * implies two splits, one between the end of the "before"
+			 * context and the start of the group, and another between
+			 * the end of the group and the beginning of the "after"
+			 * context. Some splits are aesthetically better and some
+			 * are worse. We compute a badness "score" for each split,
+			 * and add the scores for the two splits to define a
+			 * "score" for each position that the group can be shifted
+			 * to. Then we pick the shift with the lowest score.
 			 */
 			long shift, best_shift = -1;
 			struct split_score best_score;
diff --git a/third_party/git/xdiff/xemit.c b/third_party/git/xdiff/xemit.c
index 9d7d6c508749..30713ae9a98e 100644
--- a/third_party/git/xdiff/xemit.c
+++ b/third_party/git/xdiff/xemit.c
@@ -172,12 +172,10 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 	struct func_line func_line = { 0 };
 
 	for (xch = xscr; xch; xch = xche->next) {
-		xdchange_t *xchp = xch;
 		xche = xdl_get_hunk(&xch, xecfg);
 		if (!xch)
 			break;
 
-pre_context_calculation:
 		s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
 		s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
 
@@ -214,21 +212,6 @@ pre_context_calculation:
 			if (fs1 < s1) {
 				s2 = XDL_MAX(s2 - (s1 - fs1), 0);
 				s1 = fs1;
-
-				/*
-				 * Did we extend context upwards into an
-				 * ignored change?
-				 */
-				while (xchp != xch &&
-				       xchp->i1 + xchp->chg1 <= s1 &&
-				       xchp->i2 + xchp->chg2 <= s2)
-					xchp = xchp->next;
-
-				/* If so, show it after all. */
-				if (xchp != xch) {
-					xch = xchp;
-					goto pre_context_calculation;
-				}
 			}
 		}