add --overwrite option to ignore file conflicts

Allows for safer, more fine-grained control for overwriting files than
--force's all-or-nothing approach.

Implements FS#31549.

Signed-off-by: Andrew Gregory <andrew.gregory.8@gmail.com>
Signed-off-by: Allan McRae <allan@archlinux.org>

doc/pacman.8.txt

@@ -270,6 +270,18 @@ Upgrade Options (apply to '-S' and '-U')[[UO]]
 *\--needed*::
 	Do not reinstall the targets that are already up-to-date.
 
+*\--overwrite* <glob>::
+	Bypass file conflict checks and overwrite conflicting files. If the
+	package that is about to be installed contains files that are already
+	installed and match 'glob', this option will cause all those files to be
+	overwritten.  Using '\--overwrite' will not allow overwriting a directory
+	with a file or installing packages with conflicting files and directories.
+	Multiple patterns can be specified by separating them with a comma. May be
+	specified multiple times.  Patterns can be negated, such that files
+	matching them will not be overwritten, by prefixing them with an
+	exclamation mark. Subsequent matches will override previous ones. A leading
+	literal exclamation mark or backslash needs to be escaped.
+
 
 Query Options (apply to '-Q')[[QO]]
 -----------------------------------

lib/libalpm/alpm.h

@@ -830,6 +830,11 @@ int alpm_option_add_hookdir(alpm_handle_t *handle, const char *hookdir);
 int alpm_option_remove_hookdir(alpm_handle_t *handle, const char *hookdir);
 /** @} */
 
+alpm_list_t *alpm_option_get_overwrite_files(alpm_handle_t *handle);
+int alpm_option_set_overwrite_files(alpm_handle_t *handle, alpm_list_t *globs);
+int alpm_option_add_overwrite_file(alpm_handle_t *handle, const char *glob);
+int alpm_option_remove_overwrite_file(alpm_handle_t *handle, const char *glob);
+
 /** Returns the logfile name. */
 const char *alpm_option_get_logfile(alpm_handle_t *handle);
 /** Sets the logfile name. */

lib/libalpm/conflict.c

@@ -385,6 +385,12 @@ static alpm_list_t *alpm_db_find_file_owners(alpm_db_t* db, const char *path)
 	return owners;
 }
 
+static int _alpm_can_overwrite_file(alpm_handle_t *handle, const char *path)
+{
+	return handle->trans->flags & ALPM_TRANS_FLAG_FORCE
+		|| _alpm_fnmatch_patterns(handle->overwrite_files, path) == 0;
+}
+
 /**
  * @brief Find file conflicts that may occur during the transaction.
  *
@@ -448,8 +454,8 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 					/* can skip file-file conflicts when forced *
 					 * checking presence in p2_files detects dir-file or file-dir
 					 * conflicts as the path from p1 is returned */
-					if((handle->trans->flags & ALPM_TRANS_FLAG_FORCE) &&
-							alpm_filelist_contains(p2_files, filename)) {
+					if(_alpm_can_overwrite_file(handle, filename)
+							&& alpm_filelist_contains(p2_files, filename)) {
 						_alpm_log(handle, ALPM_LOG_DEBUG,
 							"%s exists in both '%s' and '%s'\n", filename,
 							p1->name, p2->name);
@@ -654,8 +660,8 @@ alpm_list_t *_alpm_db_find_fileconflicts(alpm_handle_t *handle,
 			}
 
 			/* skip file-file conflicts when being forced */
-			if((handle->trans->flags & ALPM_TRANS_FLAG_FORCE) &&
-					!S_ISDIR(lsbuf.st_mode)) {
+			if(!S_ISDIR(lsbuf.st_mode)
+					&& _alpm_can_overwrite_file(handle, filestr)) {
 				_alpm_log(handle, ALPM_LOG_DEBUG,
 							"conflict with file on filesystem being forced\n");
 				resolved_conflict = 1;

lib/libalpm/handle.c

@@ -283,6 +283,12 @@ alpm_list_t SYMEXPORT *alpm_option_get_ignoregroups(alpm_handle_t *handle)
 	return handle->ignoregroup;
 }
 
+alpm_list_t SYMEXPORT *alpm_option_get_overwrite_files(alpm_handle_t *handle)
+{
+	CHECK_HANDLE(handle, return NULL);
+	return handle->overwrite_files;
+}
+
 alpm_list_t SYMEXPORT *alpm_option_get_assumeinstalled(alpm_handle_t *handle)
 {
 	CHECK_HANDLE(handle, return NULL);
@@ -657,6 +663,21 @@ int SYMEXPORT alpm_option_remove_ignoregroup(alpm_handle_t *handle, const char *
 	return _alpm_option_strlist_rem(handle, &(handle->ignoregroup), grp);
 }
 
+int SYMEXPORT alpm_option_add_overwrite_file(alpm_handle_t *handle, const char *glob)
+{
+	return _alpm_option_strlist_add(handle, &(handle->overwrite_files), glob);
+}
+
+int SYMEXPORT alpm_option_set_overwrite_files(alpm_handle_t *handle, alpm_list_t *globs)
+{
+	return _alpm_option_strlist_set(handle, &(handle->overwrite_files), globs);
+}
+
+int SYMEXPORT alpm_option_remove_overwrite_file(alpm_handle_t *handle, const char *glob)
+{
+	return _alpm_option_strlist_rem(handle, &(handle->overwrite_files), glob);
+}
+
 int SYMEXPORT alpm_option_add_assumeinstalled(alpm_handle_t *handle, const alpm_depend_t *dep)
 {
 	alpm_depend_t *depcpy;

lib/libalpm/handle.h

@@ -84,6 +84,7 @@ struct __alpm_handle_t {
 	char *gpgdir;            /* Directory where GnuPG files are stored */
 	alpm_list_t *cachedirs;  /* Paths to pacman cache directories */
 	alpm_list_t *hookdirs;   /* Paths to hook directories */
+	alpm_list_t *overwrite_files; /* Paths that may be overwritten */
 
 	/* package lists */
 	alpm_list_t *noupgrade;   /* List of packages NOT to be upgraded */

src/pacman/conf.c

@@ -783,6 +783,8 @@ static int setup_libalpm(void)
 		alpm_option_set_cachedirs(handle, config->cachedirs);
 	}
 
+	alpm_option_set_overwrite_files(handle, config->overwrite_files);
+
 	alpm_option_set_default_siglevel(handle, config->siglevel);
 
 	config->localfilesiglevel = merge_siglevel(config->siglevel,

src/pacman/conf.h

@@ -123,6 +123,7 @@ typedef struct __config_t {
 	alpm_list_t *assumeinstalled;
 	alpm_list_t *noupgrade;
 	alpm_list_t *noextract;
+	alpm_list_t *overwrite_files;
 	char *xfercommand;
 
 	/* our connection to libalpm */
@@ -172,6 +173,7 @@ enum {
 	OP_GPGDIR,
 	OP_DBONLY,
 	OP_FORCE,
+	OP_OVERWRITE_FILES,
 	OP_COLOR,
 	OP_DBPATH,
 	OP_CASCADE,

src/pacman/pacman.c

@@ -190,6 +190,8 @@ static void usage(int op, const char * const myname)
 			case PM_OP_SYNC:
 			case PM_OP_UPGRADE:
 				addlist(_("      --force          force install, overwrite conflicting files\n"));
+				addlist(_("      --overwrite <path>\n"
+				          "                       overwrite conflicting files (can be used more than once)\n"));
 				addlist(_("      --asdeps         install packages as non-explicitly installed\n"));
 				addlist(_("      --asexplicit     install packages as explicitly installed\n"));
 				addlist(_("      --ignore <pkg>   ignore a package upgrade (can be used more than once)\n"));
@@ -708,6 +710,9 @@ static int parsearg_upgrade(int opt)
 		case OP_FORCE:
 			config->flags |= ALPM_TRANS_FLAG_FORCE;
 			break;
+		case OP_OVERWRITE_FILES:
+			parsearg_util_addlist(&(config->overwrite_files));
+			break;
 		case OP_ASDEPS:
 			config->flags |= ALPM_TRANS_FLAG_ALLDEPS;
 			break;
@@ -929,6 +934,7 @@ static int parseargs(int argc, char *argv[])
 		{"assume-installed",     required_argument, 0, OP_ASSUMEINSTALLED},
 		{"debug",      optional_argument, 0, OP_DEBUG},
 		{"force",      no_argument,       0, OP_FORCE},
+		{"overwrite",  required_argument, 0, OP_OVERWRITE_FILES},
 		{"noprogressbar", no_argument,    0, OP_NOPROGRESSBAR},
 		{"noscriptlet", no_argument,      0, OP_NOSCRIPTLET},
 		{"ask",        required_argument, 0, OP_ASK},

test/pacman/tests/TESTS

@@ -80,6 +80,9 @@ TESTS += test/pacman/tests/mode001.py
 TESTS += test/pacman/tests/mode002.py
 TESTS += test/pacman/tests/mode003.py
 TESTS += test/pacman/tests/noupgrade-inverted.py
+TESTS += test/pacman/tests/overwrite-files-match-negated.py
+TESTS += test/pacman/tests/overwrite-files-match.py
+TESTS += test/pacman/tests/overwrite-files-nonmatch.py
 TESTS += test/pacman/tests/pacman001.py
 TESTS += test/pacman/tests/pacman002.py
 TESTS += test/pacman/tests/pacman003.py

test/pacman/tests/overwrite-files-match-negated.py

@@ -0,0 +1,13 @@
+self.description = "Install a package with an existing file matching a negated --overwrite pattern"
+
+p = pmpkg("dummy")
+p.files = ["foobar"]
+self.addpkg(p)
+
+self.filesystem = ["foobar*"]
+
+self.args = "-U --overwrite=foobar --overwrite=!foo* %s" % p.filename()
+
+self.addrule("!PACMAN_RETCODE=0")
+self.addrule("!PKG_EXIST=dummy")
+self.addrule("!FILE_MODIFIED=foobar")

test/pacman/tests/overwrite-files-match.py

@@ -0,0 +1,13 @@
+self.description = "Install a package with an existing file matching an --overwrite pattern"
+
+p = pmpkg("dummy")
+p.files = ["foobar"]
+self.addpkg(p)
+
+self.filesystem = ["foobar*"]
+
+self.args = "-U --overwrite=foobar %s" % p.filename()
+
+self.addrule("PACMAN_RETCODE=0")
+self.addrule("PKG_EXIST=dummy")
+self.addrule("FILE_MODIFIED=foobar")

test/pacman/tests/overwrite-files-nonmatch.py

@@ -0,0 +1,13 @@
+self.description = "Install a package with an existing file not matching --overwrite patterns"
+
+p = pmpkg("dummy")
+p.files = ["foobar"]
+self.addpkg(p)
+
+self.filesystem = ["foobar*"]
+
+self.args = "-U --overwrite=foo %s" % p.filename()
+
+self.addrule("!PACMAN_RETCODE=0")
+self.addrule("!PKG_EXIST=dummy")
+self.addrule("!FILE_MODIFIED=foobar")