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Merged
twaugh merged 4 commits into from
Aug 20, 2025
Merged

Automatic -p option #76

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493dde8
When no -p option is given, determine a sensible one
twaugh Aug 20, 2025
486d726
Whitespace changes
twaugh Aug 20, 2025
5217b1b
Additional tests
twaugh Aug 20, 2025
e18a5dc
Update documentation
twaugh Aug 20, 2025
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7 changes: 7 additions & 0 deletions Makefile.am
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Original file line number Diff line number Diff line change
Expand Up @@ -116,6 +116,13 @@ TESTS = tests/newline1/run-test \
tests/combine2/run-test \
tests/combine3/run-test \
tests/combine4/run-test \
tests/combine5/run-test \
tests/combine6/run-test \
tests/combine-devnull/run-test \
tests/combine-devnull-p/run-test \
tests/combine-no-match/run-test \
tests/interdiff-devnull/run-test \
tests/flipdiff-devnull/run-test \
tests/gendiff1/run-test \
tests/gendiff2/run-test \
tests/comma/run-test \
Expand Down
18 changes: 15 additions & 3 deletions doc/patchutils.xml
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Expand Up @@ -162,7 +162,11 @@
<option>-p</option> option to GNU <citerefentry>
<refentrytitle>patch</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry>.)</para>
</citerefentry>.) If this option is not specified,
<command>interdiff</command> will automatically
determine the optimal number of path components to
strip by finding the smallest value where at least
one file matches between the two patches.</para>
</listitem>
</varlistentry>

Expand Down Expand Up @@ -464,7 +468,11 @@
<option>-p</option> option to GNU <citerefentry>
<refentrytitle>patch</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry>.)</para>
</citerefentry>.) If this option is not specified,
<command>combinediff</command> will automatically
determine the optimal number of path components to
strip by finding the smallest value where at least
one file matches between the two patches.</para>
</listitem>
</varlistentry>

Expand Down Expand Up @@ -2922,7 +2930,11 @@ will pipe patch of file #2 to vim - -R
<option>-p</option> option to GNU <citerefentry>
<refentrytitle>patch</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry>.)</para>
</citerefentry>.) If this option is not specified,
<command>flipdiff</command> will automatically
determine the optimal number of path components to
strip by finding the smallest value where at least
one file matches between the two patches.</para>
</listitem>
</varlistentry>

Expand Down
168 changes: 124 additions & 44 deletions src/interdiff.c
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Original file line number Diff line number Diff line change
Expand Up @@ -95,6 +95,7 @@ static int num_diff_opts = 0;
static unsigned int max_context_real = 3, max_context = 3;
static int context_specified = 0;
static int ignore_components = 0;
static int ignore_components_specified = 0;
static int unzip = 0;
static int no_revert_omitted = 0;
static int debug = 0;
Expand All @@ -103,6 +104,7 @@ static struct patlist *pat_drop_context = NULL;

static struct file_list *files_done = NULL;
static struct file_list *files_in_patch2 = NULL;
static struct file_list *files_in_patch1 = NULL;

/* checks whether file needs processing and sets context */
static int
Expand Down Expand Up @@ -147,6 +149,49 @@ file_in_list (struct file_list *list, const char *file)
return -1;
}

/* Determine the best ignore_components value when none was specified.
* Try different values from 0 up to a reasonable maximum, and find the
* smallest value where at least one file from patch1 matches a file from patch2.
*/
static int
determine_ignore_components (struct file_list *list1, struct file_list *list2)
{
int max_components = 0;
int p;

/* Find the maximum number of path components in any file */
for (struct file_list *l = list1; l; l = l->next) {
if (strcmp(l->file, "/dev/null") != 0) {
int components = num_pathname_components(l->file);
if (components > max_components)
max_components = components;
}
}
for (struct file_list *l = list2; l; l = l->next) {
if (strcmp(l->file, "/dev/null") != 0) {
int components = num_pathname_components(l->file);
if (components > max_components)
max_components = components;
}
}

/* Try different -p values, starting from 0 */
for (p = 0; p <= max_components; p++) {
for (struct file_list *l1 = list1; l1; l1 = l1->next) {
const char *stripped1 = stripped(l1->file, p);
for (struct file_list *l2 = list2; l2; l2 = l2->next) {
const char *stripped2 = stripped(l2->file, p);
if (!strcmp(stripped1, stripped2)) {
return p;
}
}
}
}

/* If no match found, return 0 as default */
return 0;
}

static void
free_list (struct file_list *list)
{
Expand Down Expand Up @@ -178,7 +223,7 @@ add_line (struct lines_info *lines, const char *line, size_t length,
{
struct lines *make;
struct lines *at;

make = xmalloc (sizeof *make);
make->n = n;
make->line = xmalloc (length + 1);
Expand Down Expand Up @@ -243,7 +288,7 @@ merge_lines (struct lines_info *lines1, struct lines_info *lines2)
struct lines *at, *at_prev, *make;


/*
/*
* Note: we don't care about the tail member here - not needed
* anymore.
*/
Expand Down Expand Up @@ -619,7 +664,7 @@ do_output_patch1_only (FILE *p1, FILE *out, int not_reverted)
orig_lines = orig_num_lines (d1);
new_lines = new_num_lines (d2);
}


free (d1);
free (d2);
Expand Down Expand Up @@ -1138,7 +1183,7 @@ output_delta (FILE *p1, FILE *p2, FILE *out)
memcpy (argv + 2, diff_opts, num_diff_opts * sizeof (char *));
memcpy (argv + 2 + num_diff_opts, (char *[]) { tmpp1, tmpp2, NULL }, (2 + 1) * sizeof (char *));
in = xpipe (DIFF, &child, "r", argv);

/* Eat the first line */
for (;;) {
int ch = fgetc (in);
Expand Down Expand Up @@ -1270,22 +1315,23 @@ copy_residue (FILE *p2, FILE *out)
return 0;
}

/* Generic patch indexing function that can handle both patch1 and patch2 */
static int
index_patch2 (FILE *p2)
index_patch_generic (FILE *patch_file, struct file_list **file_list, int need_skip_content)
{
char *line = NULL;
size_t linelen = 0;
int is_context = 0;
int file_is_empty = 1;

/* Index patch2 */
while (!feof (p2)) {
/* Index patch */
while (!feof (patch_file)) {
unsigned long skip;
char *names[2];
char *p, *end;
long pos = ftell (p2);
long pos = ftell (patch_file);

if (getline (&line, &linelen, p2) == -1)
if (getline (&line, &linelen, patch_file) == -1)
break;

file_is_empty = 0;
Expand All @@ -1301,7 +1347,7 @@ index_patch2 (FILE *p2)

names[0] = filename_from_header (line + 4);

if (getline (&line, &linelen, p2) == -1) {
if (getline (&line, &linelen, patch_file) == -1) {
free (names[0]);
break;
}
Expand All @@ -1313,38 +1359,44 @@ index_patch2 (FILE *p2)

names[1] = filename_from_header (line + 4);

if (getline (&line, &linelen, p2) == -1) {
free (names[0]);
free (names[1]);
break;
}

if (strncmp (line, "@@ ", 3))
goto try_next;
/* For patch2, we need to handle the @@ line and skip content */
if (need_skip_content) {
if (getline (&line, &linelen, patch_file) == -1) {
free (names[0]);
free (names[1]);
break;
}

p = strchr (line + 3, '+');
if (!p)
goto try_next;
p = strchr (p, ',');
if (p) {
/* Like '@@ -1,3 +1,3 @@' */
p++;
skip = strtoul (p, &end, 10);
if (p == end)
if (strncmp (line, "@@ ", 3))
goto try_next;
} else
/* Like '@@ -1 +1 @@' */
skip = 1;

add_to_list (&files_in_patch2, best_name (2, names), pos);

while (skip--) {
if (getline (&line, &linelen, p2) == -1)
break;

if (line[0] == '-')
/* Doesn't count towards skip count */
skip++;
p = strchr (line + 3, '+');
if (!p)
goto try_next;
p = strchr (p, ',');
if (p) {
/* Like '@@ -1,3 +1,3 @@' */
p++;
skip = strtoul (p, &end, 10);
if (p == end)
goto try_next;
} else
/* Like '@@ -1 +1 @@' */
skip = 1;

add_to_list (file_list, best_name (2, names), pos);

while (skip--) {
if (getline (&line, &linelen, patch_file) == -1)
break;

if (line[0] == '-')
/* Doesn't count towards skip count */
skip++;
}
} else {
/* For patch1, just add to list */
add_to_list (file_list, best_name (2, names), pos);
}

try_next:
Expand All @@ -1355,12 +1407,18 @@ index_patch2 (FILE *p2)
if (line)
free (line);

if (file_is_empty || files_in_patch2)
if (file_is_empty || *file_list)
return 0;
else
return 1;
}

static int
index_patch2 (FILE *p2)
{
return index_patch_generic (p2, &files_in_patch2, 1);
}

/* With flipdiff we have two patches we want to reorder. The
* algorithm is:
*
Expand Down Expand Up @@ -1424,7 +1482,7 @@ patch2_removes_line (unsigned long line, /* line number after patch1 */
return 1;
}
}

return 0;
}

Expand Down Expand Up @@ -1908,6 +1966,12 @@ no_patch (const char *f)
return 0;
}

static int
index_patch1 (FILE *p1)
{
return index_patch_generic (p1, &files_in_patch1, 0);
}

static int
interdiff (FILE *p1, FILE *p2, const char *patch1, const char *patch2)
{
Expand All @@ -1926,6 +1990,20 @@ interdiff (FILE *p1, FILE *p2, const char *patch1, const char *patch2)
if (index_patch2 (p2))
no_patch (patch2);

/* Index patch1 and determine ignore_components if not specified */
if (index_patch1 (p1))
no_patch (patch1);

/* Determine ignore_components automatically if not explicitly specified */
if (!ignore_components_specified) {
ignore_components = determine_ignore_components (files_in_patch1, files_in_patch2);
if (debug)
fprintf (stderr, "Auto-determined -p%d\n", ignore_components);
}

/* Reset file pointer for patch1 */
rewind (p1);

/* Search for next file to patch */
while (!feof (p1)) {
char *names[2];
Expand Down Expand Up @@ -1966,7 +2044,7 @@ interdiff (FILE *p1, FILE *p2, const char *patch1, const char *patch2)
free (names[0]);
free (names[1]);
patch_found = 1;

/* check if we need to process it and init context */
if (!check_filename(p)) {
add_to_list (&files_done, p, 0);
Expand Down Expand Up @@ -2020,6 +2098,7 @@ interdiff (FILE *p1, FILE *p2, const char *patch1, const char *patch2)
fclose (flip1);
if (flip2)
fclose (flip2);
free_list (files_in_patch1);
free_list (files_in_patch2);
free_list (files_done);
if (line)
Expand Down Expand Up @@ -2163,6 +2242,7 @@ main (int argc, char *argv[])
ignore_components = strtoul (optarg, &end, 0);
if (optarg == end)
syntax (1);
ignore_components_specified = 1;
break;
case 'q':
human_readable = 0;
Expand Down Expand Up @@ -2221,7 +2301,7 @@ main (int argc, char *argv[])
if (unzip && flipdiff_inplace)
error (EXIT_FAILURE, 0,
"-z and --in-place are mutually exclusive.");

/* Add default color=always if no color option was specified and we're in a terminal */
int has_color_option = 0;
for (int i = 0; i < num_diff_opts; i++) {
Expand All @@ -2237,7 +2317,7 @@ main (int argc, char *argv[])

if (optind + 2 != argc)
syntax (1);

if (unzip) {
p1 = xopen_unzip (argv[optind], "rb");
p2 = xopen_unzip (argv[optind + 1], "rb");
Expand Down
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