Remove extra field information when using zip_replace().

The extra field information is usually dependent on the file data.
nih-at · Mar 18, 2024 · 802fef0 · 802fef0
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diff --git a/NEWS.md b/NEWS.md
@@ -3,7 +3,8 @@
 * Only write Zip64 EOCD if fields don't fit in normal EOCD. Previously libzip also wrote it when any directory entry required Zip64.
 * Allow bytes from 0x00-0x1F as UTF-8.
 * Add new error code `ZIP_ER_TRUNCATED_ZIP` for files that start with a valid local header signature.
-* `zipcmp`: add `-T` option for comparing timestamps
+* `zipcmp`: add `-T` option for comparing timestamps.
+* `zip_file_replace` now removes the target's extra field information.
 
 # 1.10.1 [2023-08-23]
 

diff --git a/TODO.md b/TODO.md
@@ -49,7 +49,6 @@ const zip_uint8_t *zip_get_archive_prefix(struct zip *za, zip_uint64_t *lengthp)
   * allow invalid data flag, used when computing extra field size before writing data
   * new command `ZIP_SOURCE_EXTRA_FIELDS`
   * no support for multiple copies of same extra field
-* delete all extra fields during `zip_replace()`
 * function to copy file from one archive to another
 * set `O_CLOEXEC` flag after fopen and mkstemp
 * support streaming output (creating new archive to e.g. stdout)

diff --git a/lib/zip_file_replace.c b/lib/zip_file_replace.c
@@ -83,6 +83,12 @@ _zip_file_replace(zip_t *za, zip_uint64_t idx, const char *name, zip_source_t *s
         return -1;
     }
 
+    /* delete all extra fields - these are usually data that are
+     * strongly coupled with the original data */
+    if (zip_file_extra_field_delete(za, idx, ZIP_EXTRA_FIELD_ALL, ZIP_FL_CENTRAL | ZIP_FL_LOCAL) < 0) {
+        return -1;
+    }
+
     /* does not change any name related data, so we can do it here;
      * needed for a double add of the same file name */
     _zip_unchange_data(za->entry + idx);

diff --git a/man/zip_file_add.mdoc b/man/zip_file_add.mdoc
@@ -29,7 +29,7 @@
 .\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 .\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd September 22, 2020
+.Dd March 18, 2024
 .Dt ZIP_FILE_ADD 3
 .Os
 .Sh NAME
@@ -100,6 +100,17 @@ after it was used successfully in a
 or
 .Nm zip_file_replace
 call.
+.Pp
+Please also note that when using
+.Nm zip_replace ,
+the target file's extra field information will be deleted since this
+usually is dependent on the file contents.
+If you want to keep them, query them beforehand with
+.Xr zip_file_extra_field_get 3
+and restore them after
+.Nm zip_replace
+with
+.Xr zip_file_extra_field_set 3 .
 .Sh RETURN VALUES
 Upon successful completion,
 .Fn zip_file_add

diff --git a/regress/utf-8-standardization-output.zip b/regress/utf-8-standardization-output.zip