Consider two patches, each of which patches the same set of multiple source files, in the same order. The base revision number of ONE of the source files in those two patches is different between the two patches. When one attempts to view the differences between those two patches with buzilla's interdiff feature, one might expect the result to show the differences between all the files *except* the one source file whose version number was not the same in the two patches. However what actually happens is that the result shows only the diffs between the FIRST file in each of the two patches, and does NOT show the diffs for any of the other files, even the ones for which the version numbers were unchanged. This problem is seen in the URL https://bugzilla.mozilla.org/attachment.cgi?oldid=194281&action=interdiff&newid=195237&headers=1 The two patches being diffed, which may be seen at https://bugzilla.mozilla.org/attachment.cgi?id=194281&action=diff https://bugzilla.mozilla.org/attachment.cgi?id=195237&action=diff patch the same set of 11 files, in the same order. Both patches were produced with "cvs diff -u5" in the same directory. However, one of the files, the 7th one of the 11 files, changed version numbers between the two patches. A checkin was made to that file that did not affect the patch at all, except that it changed the base version number given in the diff output. This one change causes the Interdiff feature to show the diffs for only 1 of the 11 files (the first one). Expected result: see diffs for 10 of the 11 files, but not the one file whose version number changed. Actual result: see diffs for only one of the 11 files, the first one in the patch.

looks like a dupe of bug 210407.

Agreed. *** This bug has been marked as a duplicate of 210407 ***