Hi, On Tue, 24 Mar 2020, Danh Doan wrote: > On 2020-03-23 13:50:48-0700, Junio C Hamano <gitster@xxxxxxxxx> wrote: > > Danh Doan <congdanhqx@xxxxxxxxx> writes: > > > > > A comment in test-lib-functions::test_cmp mentions that > > > there _is_ a diff out there that doesn't understand "-u". > > > > That came from 82ebb0b6 (add test_cmp function for test scripts, > > 2008-03-12). > > > > The change history at the end of the page: > > > > https://pubs.opengroup.org/onlinepubs/9699919799/utilities/diff.html > > > > suggests that POSIX did not require "diff -u" until Issue 7, so it > > is not surprising that the lack of "diff -u" to cause test_cmp to > > fail was of real concern back in March 2008, as the application of > > the errata have been only an year and half old, according to: > > > > https://www.opengroup.org/austin/docs/austin_325.txt > > > > I vaguely recall that some open source projects only took the copied > > context diffs and not unified ones the last time I checked, but > > admittedly (1) that "last time" was a long time ago and (2) our > > popularity and the fact that we do not understand copied context > > [*1*] may have forced people to move away from "-c" and adopt "-u" > > at the same time. > > > > So it might be OK to write off any system that does not understand > > "diff -u" as an unusable trash these days ;-) > > From the setting in "config.mak.uname", it's likely those systems > don't understand "diff -u": > > - Solaris 5.6, 5.7, 5.8, 5.9: both of them are un-supported version > by their vendor > - AIX, only AIX 5.3 doesn't understand "-u", > the end-of-support AIX 6.1's diff(1) understand "-u" (1) > - HP-UX: From what I can collect, HP-UX still conforms to UNIX-03, and > its diff(1) doesn't understand "-u" > > Hence, if we're going to drop support for system that doesn't > understand "diff -u", we're going to: > - remove support for those variables: > + GIT_TEST_CMP_USE_COPIED_CONTEXT > + GIT_TEST_CMP > - drop support for: > + Solaris 5.{6,7,8,} and AIX 5.3, which will be fine > + HP-UX: which needs to be discussed > > [1]: https://public.dhe.ibm.com/systems/power/docs/aix/61/aixcmds2_pdf.pdf page 133(143) With this explanation, I totally agree that your patch is better than mine. Thanks, Dscho
