Merge branch 'jk/xdiff-clamp-funcname-context-index' into maint

The internal diff machinery can be made to read out of bounds while
looking for --funcion-context line in a corner case, which has been
corrected.

* jk/xdiff-clamp-funcname-context-index:
xdiff: clamp function context indices in post-image

diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index ab4670d23653eca46292b13ef1559584aae5c3a6..6b087df3dcbd01df9c7e533f9e039518beaa773a 100755 (executable)
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -2008,4 +2008,26 @@ 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 &&
+       test_must_fail git diff --no-index \
+               --ignore-blank-lines --function-context a b >actual.raw &&
+       sed -n "/@@/,\$p" <actual.raw >actual &&
+       cat <<-\EOF >expect &&
+       @@ -1,6 +1,4 @@
+        1
+        2
+        3
+        4
+       -5
+       EOF
+       test_cmp expect actual
+'
+
 test_done

diff --git a/xdiff/xemit.c b/xdiff/xemit.c
index 7778dc2b190f84fe2ab1e1539756a7e1f4254c3b..30713ae9a98ecfc9f764120d3a1d18b5a8ee11bf 100644 (file)
--- a/xdiff/xemit.c
+++ b/xdiff/xemit.c
@@ -210,7 +210,7 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
                        if (fs1 < 0)
                                fs1 = 0;
                        if (fs1 < s1) {
-                               s2 -= s1 - fs1;
+                               s2 = XDL_MAX(s2 - (s1 - fs1), 0);
                                s1 = fs1;
                        }
                }
@@ -232,7 +232,7 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
                        if (fe1 < 0)
                                fe1 = xe->xdf1.nrec;
                        if (fe1 > e1) {
-                               e2 += fe1 - e1;
+                               e2 = XDL_MIN(e2 + (fe1 - e1), xe->xdf2.nrec);
                                e1 = fe1;
                        }