fully resolve symlinks when creating lockfiles
[gitweb.git] / merge-recursive.c
index 31e66e5ca3811d6356a635ef7580e86ce9c83863..c8539ec0bafce5e238d97d6397a9d08c2c92a09c 100644 (file)
@@ -15,6 +15,8 @@
 #include "unpack-trees.h"
 #include "path-list.h"
 #include "xdiff-interface.h"
+#include "interpolate.h"
+#include "attr.h"
 
 static int subtree_merge;
 
@@ -125,7 +127,7 @@ static void output(int v, const char *fmt, ...)
        va_end(args);
 }
 
-static void flush_output()
+static void flush_output(void)
 {
        struct output_buffer *b, *n;
        for (b = output_list; b; b = n) {
@@ -645,6 +647,390 @@ static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
        mm->size = size;
 }
 
+/*
+ * Customizable low-level merge drivers support.
+ */
+
+struct ll_merge_driver;
+typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
+                          const char *path,
+                          mmfile_t *orig,
+                          mmfile_t *src1, const char *name1,
+                          mmfile_t *src2, const char *name2,
+                          mmbuffer_t *result);
+
+struct ll_merge_driver {
+       const char *name;
+       const char *description;
+       ll_merge_fn fn;
+       const char *recursive;
+       struct ll_merge_driver *next;
+       char *cmdline;
+};
+
+/*
+ * Built-in low-levels
+ */
+static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
+                       const char *path_unused,
+                       mmfile_t *orig,
+                       mmfile_t *src1, const char *name1,
+                       mmfile_t *src2, const char *name2,
+                       mmbuffer_t *result)
+{
+       xpparam_t xpp;
+
+       if (buffer_is_binary(orig->ptr, orig->size) ||
+                       buffer_is_binary(src1->ptr, src1->size) ||
+                       buffer_is_binary(src2->ptr, src2->size))
+               return error("Cannot merge binary files: %s vs. %s\n",
+                       name1, name2);
+
+       memset(&xpp, 0, sizeof(xpp));
+       return xdl_merge(orig,
+                        src1, name1,
+                        src2, name2,
+                        &xpp, XDL_MERGE_ZEALOUS,
+                        result);
+}
+
+static int ll_union_merge(const struct ll_merge_driver *drv_unused,
+                         const char *path_unused,
+                         mmfile_t *orig,
+                         mmfile_t *src1, const char *name1,
+                         mmfile_t *src2, const char *name2,
+                         mmbuffer_t *result)
+{
+       char *src, *dst;
+       long size;
+       const int marker_size = 7;
+
+       int status = ll_xdl_merge(drv_unused, path_unused,
+                                 orig, src1, NULL, src2, NULL, result);
+       if (status <= 0)
+               return status;
+       size = result->size;
+       src = dst = result->ptr;
+       while (size) {
+               char ch;
+               if ((marker_size < size) &&
+                   (*src == '<' || *src == '=' || *src == '>')) {
+                       int i;
+                       ch = *src;
+                       for (i = 0; i < marker_size; i++)
+                               if (src[i] != ch)
+                                       goto not_a_marker;
+                       if (src[marker_size] != '\n')
+                               goto not_a_marker;
+                       src += marker_size + 1;
+                       size -= marker_size + 1;
+                       continue;
+               }
+       not_a_marker:
+               do {
+                       ch = *src++;
+                       *dst++ = ch;
+                       size--;
+               } while (ch != '\n' && size);
+       }
+       result->size = dst - result->ptr;
+       return 0;
+}
+
+static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
+                          const char *path_unused,
+                          mmfile_t *orig,
+                          mmfile_t *src1, const char *name1,
+                          mmfile_t *src2, const char *name2,
+                          mmbuffer_t *result)
+{
+       /*
+        * The tentative merge result is "ours" for the final round,
+        * or common ancestor for an internal merge.  Still return
+        * "conflicted merge" status.
+        */
+       mmfile_t *stolen = index_only ? orig : src1;
+
+       result->ptr = stolen->ptr;
+       result->size = stolen->size;
+       stolen->ptr = NULL;
+       return 1;
+}
+
+#define LL_BINARY_MERGE 0
+#define LL_TEXT_MERGE 1
+#define LL_UNION_MERGE 2
+static struct ll_merge_driver ll_merge_drv[] = {
+       { "binary", "built-in binary merge", ll_binary_merge },
+       { "text", "built-in 3-way text merge", ll_xdl_merge },
+       { "union", "built-in union merge", ll_union_merge },
+};
+
+static void create_temp(mmfile_t *src, char *path)
+{
+       int fd;
+
+       strcpy(path, ".merge_file_XXXXXX");
+       fd = mkstemp(path);
+       if (fd < 0)
+               die("unable to create temp-file");
+       if (write_in_full(fd, src->ptr, src->size) != src->size)
+               die("unable to write temp-file");
+       close(fd);
+}
+
+/*
+ * User defined low-level merge driver support.
+ */
+static int ll_ext_merge(const struct ll_merge_driver *fn,
+                       const char *path,
+                       mmfile_t *orig,
+                       mmfile_t *src1, const char *name1,
+                       mmfile_t *src2, const char *name2,
+                       mmbuffer_t *result)
+{
+       char temp[3][50];
+       char cmdbuf[2048];
+       struct interp table[] = {
+               { "%O" },
+               { "%A" },
+               { "%B" },
+       };
+       struct child_process child;
+       const char *args[20];
+       int status, fd, i;
+       struct stat st;
+
+       if (fn->cmdline == NULL)
+               die("custom merge driver %s lacks command line.", fn->name);
+
+       result->ptr = NULL;
+       result->size = 0;
+       create_temp(orig, temp[0]);
+       create_temp(src1, temp[1]);
+       create_temp(src2, temp[2]);
+
+       interp_set_entry(table, 0, temp[0]);
+       interp_set_entry(table, 1, temp[1]);
+       interp_set_entry(table, 2, temp[2]);
+
+       output(1, "merging %s using %s", path,
+              fn->description ? fn->description : fn->name);
+
+       interpolate(cmdbuf, sizeof(cmdbuf), fn->cmdline, table, 3);
+
+       memset(&child, 0, sizeof(child));
+       child.argv = args;
+       args[0] = "sh";
+       args[1] = "-c";
+       args[2] = cmdbuf;
+       args[3] = NULL;
+
+       status = run_command(&child);
+       if (status < -ERR_RUN_COMMAND_FORK)
+               ; /* failure in run-command */
+       else
+               status = -status;
+       fd = open(temp[1], O_RDONLY);
+       if (fd < 0)
+               goto bad;
+       if (fstat(fd, &st))
+               goto close_bad;
+       result->size = st.st_size;
+       result->ptr = xmalloc(result->size + 1);
+       if (read_in_full(fd, result->ptr, result->size) != result->size) {
+               free(result->ptr);
+               result->ptr = NULL;
+               result->size = 0;
+       }
+ close_bad:
+       close(fd);
+ bad:
+       for (i = 0; i < 3; i++)
+               unlink(temp[i]);
+       return status;
+}
+
+/*
+ * merge.default and merge.driver configuration items
+ */
+static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
+static const char *default_ll_merge;
+
+static int read_merge_config(const char *var, const char *value)
+{
+       struct ll_merge_driver *fn;
+       const char *ep, *name;
+       int namelen;
+
+       if (!strcmp(var, "merge.default")) {
+               if (value)
+                       default_ll_merge = strdup(value);
+               return 0;
+       }
+
+       /*
+        * We are not interested in anything but "merge.<name>.variable";
+        * especially, we do not want to look at variables such as
+        * "merge.summary", "merge.tool", and "merge.verbosity".
+        */
+       if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
+               return 0;
+
+       /*
+        * Find existing one as we might be processing merge.<name>.var2
+        * after seeing merge.<name>.var1.
+        */
+       name = var + 6;
+       namelen = ep - name;
+       for (fn = ll_user_merge; fn; fn = fn->next)
+               if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
+                       break;
+       if (!fn) {
+               char *namebuf;
+               fn = xcalloc(1, sizeof(struct ll_merge_driver));
+               namebuf = xmalloc(namelen + 1);
+               memcpy(namebuf, name, namelen);
+               namebuf[namelen] = 0;
+               fn->name = namebuf;
+               fn->fn = ll_ext_merge;
+               fn->next = NULL;
+               *ll_user_merge_tail = fn;
+               ll_user_merge_tail = &(fn->next);
+       }
+
+       ep++;
+
+       if (!strcmp("name", ep)) {
+               if (!value)
+                       return error("%s: lacks value", var);
+               fn->description = strdup(value);
+               return 0;
+       }
+
+       if (!strcmp("driver", ep)) {
+               if (!value)
+                       return error("%s: lacks value", var);
+               /*
+                * merge.<name>.driver specifies the command line:
+                *
+                *      command-line
+                *
+                * The command-line will be interpolated with the following
+                * tokens and is given to the shell:
+                *
+                *    %O - temporary file name for the merge base.
+                *    %A - temporary file name for our version.
+                *    %B - temporary file name for the other branches' version.
+                *
+                * The external merge driver should write the results in the
+                * file named by %A, and signal that it has done with zero exit
+                * status.
+                */
+               fn->cmdline = strdup(value);
+               return 0;
+       }
+
+       if (!strcmp("recursive", ep)) {
+               if (!value)
+                       return error("%s: lacks value", var);
+               fn->recursive = strdup(value);
+               return 0;
+       }
+
+       return 0;
+}
+
+static void initialize_ll_merge(void)
+{
+       if (ll_user_merge_tail)
+               return;
+       ll_user_merge_tail = &ll_user_merge;
+       git_config(read_merge_config);
+}
+
+static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
+{
+       struct ll_merge_driver *fn;
+       const char *name;
+       int i;
+
+       initialize_ll_merge();
+
+       if (ATTR_TRUE(merge_attr))
+               return &ll_merge_drv[LL_TEXT_MERGE];
+       else if (ATTR_FALSE(merge_attr))
+               return &ll_merge_drv[LL_BINARY_MERGE];
+       else if (ATTR_UNSET(merge_attr)) {
+               if (!default_ll_merge)
+                       return &ll_merge_drv[LL_TEXT_MERGE];
+               else
+                       name = default_ll_merge;
+       }
+       else
+               name = merge_attr;
+
+       for (fn = ll_user_merge; fn; fn = fn->next)
+               if (!strcmp(fn->name, name))
+                       return fn;
+
+       for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
+               if (!strcmp(ll_merge_drv[i].name, name))
+                       return &ll_merge_drv[i];
+
+       /* default to the 3-way */
+       return &ll_merge_drv[LL_TEXT_MERGE];
+}
+
+static const char *git_path_check_merge(const char *path)
+{
+       static struct git_attr_check attr_merge_check;
+
+       if (!attr_merge_check.attr)
+               attr_merge_check.attr = git_attr("merge", 5);
+
+       if (git_checkattr(path, 1, &attr_merge_check))
+               return NULL;
+       return attr_merge_check.value;
+}
+
+static int ll_merge(mmbuffer_t *result_buf,
+                   struct diff_filespec *o,
+                   struct diff_filespec *a,
+                   struct diff_filespec *b,
+                   const char *branch1,
+                   const char *branch2)
+{
+       mmfile_t orig, src1, src2;
+       char *name1, *name2;
+       int merge_status;
+       const char *ll_driver_name;
+       const struct ll_merge_driver *driver;
+
+       name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
+       name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
+
+       fill_mm(o->sha1, &orig);
+       fill_mm(a->sha1, &src1);
+       fill_mm(b->sha1, &src2);
+
+       ll_driver_name = git_path_check_merge(a->path);
+       driver = find_ll_merge_driver(ll_driver_name);
+
+       if (index_only && driver->recursive)
+               driver = find_ll_merge_driver(driver->recursive);
+       merge_status = driver->fn(driver, a->path,
+                                 &orig, &src1, name1, &src2, name2,
+                                 result_buf);
+
+       free(name1);
+       free(name2);
+       free(orig.ptr);
+       free(src1.ptr);
+       free(src2.ptr);
+       return merge_status;
+}
+
 static struct merge_file_info merge_file(struct diff_filespec *o,
                struct diff_filespec *a, struct diff_filespec *b,
                const char *branch1, const char *branch2)
@@ -673,30 +1059,11 @@ static struct merge_file_info merge_file(struct diff_filespec *o,
                else if (sha_eq(b->sha1, o->sha1))
                        hashcpy(result.sha, a->sha1);
                else if (S_ISREG(a->mode)) {
-                       mmfile_t orig, src1, src2;
                        mmbuffer_t result_buf;
-                       xpparam_t xpp;
-                       char *name1, *name2;
                        int merge_status;
 
-                       name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
-                       name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
-
-                       fill_mm(o->sha1, &orig);
-                       fill_mm(a->sha1, &src1);
-                       fill_mm(b->sha1, &src2);
-
-                       memset(&xpp, 0, sizeof(xpp));
-                       merge_status = xdl_merge(&orig,
-                                                &src1, name1,
-                                                &src2, name2,
-                                                &xpp, XDL_MERGE_ZEALOUS,
-                                                &result_buf);
-                       free(name1);
-                       free(name2);
-                       free(orig.ptr);
-                       free(src1.ptr);
-                       free(src2.ptr);
+                       merge_status = ll_merge(&result_buf, o, a, b,
+                                               branch1, branch2);
 
                        if ((merge_status < 0) || !result_buf.ptr)
                                die("Failed to execute internal merge");
@@ -981,20 +1348,31 @@ static int process_renames(struct path_list *a_renames,
                                mfi = merge_file(o, a, b,
                                                a_branch, b_branch);
 
-                               if (mfi.merge || !mfi.clean)
-                                       output(1, "Renamed %s => %s", ren1_src, ren1_dst);
-                               if (mfi.merge)
-                                       output(2, "Auto-merged %s", ren1_dst);
-                               if (!mfi.clean) {
-                                       output(1, "CONFLICT (rename/modify): Merge conflict in %s",
-                                              ren1_dst);
-                                       clean_merge = 0;
-
-                                       if (!index_only)
-                                               update_stages(ren1_dst,
-                                                               o, a, b, 1);
+                               if (mfi.clean &&
+                                   sha_eq(mfi.sha, ren1->pair->two->sha1) &&
+                                   mfi.mode == ren1->pair->two->mode)
+                                       /*
+                                        * This messaged is part of
+                                        * t6022 test. If you change
+                                        * it update the test too.
+                                        */
+                                       output(3, "Skipped %s (merged same as existing)", ren1_dst);
+                               else {
+                                       if (mfi.merge || !mfi.clean)
+                                               output(1, "Renamed %s => %s", ren1_src, ren1_dst);
+                                       if (mfi.merge)
+                                               output(2, "Auto-merged %s", ren1_dst);
+                                       if (!mfi.clean) {
+                                               output(1, "CONFLICT (rename/modify): Merge conflict in %s",
+                                                      ren1_dst);
+                                               clean_merge = 0;
+
+                                               if (!index_only)
+                                                       update_stages(ren1_dst,
+                                                                     o, a, b, 1);
+                                       }
+                                       update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
                                }
-                               update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
                        }
                }
        }