xdiff: ignore empty lines before added functions with -W

If a new function and a preceding empty line is appended, diff -W shows the previous function in full in order to provide context for that empty line. In most languages empty lines between sections are not interesting in and off themselves and showing a whole extra function for them is not what we want. Skip empty lines when checking of the appended chunk starts with a function line, thereby avoiding to extend the context just for them. Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

René Scharfe committed May 28, 2016 at 17:02 UTC 392f6d316623e8ecd6210248ba9ae2cabf07352b
2 files changed +21 -3
t/t4051-diff-function-context.sh
+1 -1
@@ -117,7 +117,7 @@ test_expect_success ' context includes end' '
117 grep "^[+].*End of first part" appended.diff
118 '
119
120 -test_expect_failure ' context does not include other functions' '
120 +test_expect_success ' context does not include other functions' '
121 test $(grep -c "^[ +-].*Begin" appended.diff) -le 1
122 '
123
xdiff/xemit.c
+20 -2
@@ -155,6 +155,18 @@ static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
155 return -1;
156 }
157
158 +static int is_empty_rec(xdfile_t *xdf, long ri)
159 +{
160 + const char *rec;
161 + long len = xdl_get_rec(xdf, ri, &rec);
162 +
163 + while (len > 0 && XDL_ISSPACE(*rec)) {
164 + rec++;
165 + len--;
166 + }
167 + return !len;
168 +}
169 +
170 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
171 xdemitconf_t const *xecfg) {
172 long s1, s2, e1, e2, lctx;
@@ -176,12 +188,18 @@ int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
188 /* Appended chunk? */
189 if (i1 >= xe->xdf1.nrec) {
190 char dummy[1];
191 + long i2 = xch->i2;
192
193 /*
194 * We don't need additional context if
182 - * a whole function was added.
195 + * a whole function was added, possibly
196 + * starting with empty lines.
197 */
184 - if (match_func_rec(&xe->xdf2, xecfg, xch->i2,
198 + while (i2 < xe->xdf2.nrec &&
199 + is_empty_rec(&xe->xdf2, i2))
200 + i2++;
201 + if (i2 < xe->xdf2.nrec &&
202 + match_func_rec(&xe->xdf2, xecfg, i2,
203 dummy, sizeof(dummy)) >= 0)
204 goto post_context_calculation;
205