Merge branch 'rs/xdiff-ignore-ws-w-func-context'

gitster · gitster · commit f0070a7df985 · 2019-12-16T13:08:32.000-08:00
The "diff" machinery learned not to lose added/removed blank lines
in the context when --ignore-blank-lines and --function-context are
used at the same time.

* rs/xdiff-ignore-ws-w-func-context:
  xdiff: unignore changes in function context
diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
@@ -2050,11 +2050,6 @@ test_expect_success 'compare mixed whitespace delta across moved blocks' '
 	test_cmp expected actual
 '
 
-# Note that the "6" in the expected hunk header below is funny, since we only
-# show 5 lines (the missing one was blank and thus ignored). This is how
-# --ignore-blank-lines behaves even without --function-context, and this test
-# is just checking the interaction of the two features. Don't take it as an
-# endorsement of that output.
 test_expect_success 'combine --ignore-blank-lines with --function-context' '
 	test_write_lines 1 "" 2 3 4 5 >a &&
 	test_write_lines 1    2 3 4   >b &&
@@ -2064,6 +2059,7 @@ test_expect_success 'combine --ignore-blank-lines with --function-context' '
 	cat <<-\EOF >expect &&
 	@@ -1,6 +1,4 @@
 	 1
+	-
 	 2
 	 3
 	 4
diff --git a/xdiff/xemit.c b/xdiff/xemit.c
@@ -172,10 +172,12 @@ 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);
 
@@ -212,6 +214,21 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 			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;
+				}
 			}
 		}
 

Original file line number	Diff line number	Diff line change
`@@ -2050,11 +2050,6 @@ test_expect_success 'compare mixed whitespace delta across moved blocks' '`
`2050`	`2050`	`test_cmp expected actual`
`2051`	`2051`	`'`
`2052`	`2052`
`2053`		`-# Note that the "6" in the expected hunk header below is funny, since we only`
`2054`		`-# show 5 lines (the missing one was blank and thus ignored). This is how`
`2055`		`-# --ignore-blank-lines behaves even without --function-context, and this test`
`2056`		`-# is just checking the interaction of the two features. Don't take it as an`
`2057`		`-# endorsement of that output.`
`2058`	`2053`	`test_expect_success 'combine --ignore-blank-lines with --function-context' '`
`2059`	`2054`	`test_write_lines 1 "" 2 3 4 5 >a &&`
`2060`	`2055`	`test_write_lines 1 2 3 4 >b &&`
`@@ -2064,6 +2059,7 @@ test_expect_success 'combine --ignore-blank-lines with --function-context' '`
`2064`	`2059`	`cat <<-\EOF >expect &&`
`2065`	`2060`	`@@ -1,6 +1,4 @@`
`2066`	`2061`	`1`
	`2062`	`+ -`
`2067`	`2063`	`2`
`2068`	`2064`	`3`
`2069`	`2065`	`4`