bug#44616: 26.3; vc-diff and dired-diff prevent refine diff while ignoring whitespace

bug#44616: 26.3; vc-diff and dired-diff prevent refine diff while ignoring whitespace

[Francesco Potortì]

[-- Attachment #1: Type: text/plain, Size: 495 bytes --]

In GNU Emacs 26.3 (build 1, x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2020-05-17, modified by Debian built on x86-csail-01

To see the problem, launch dired-diff on the attached files (to do that,
open dired, and hit = on one of the file entries)

You see that the diff chunk differs for whitespace and case.  Try first
C-b (refine diff) and then C-w (ignore whitespace).  It is not possible
to have them both active at the same time, while it should.

The same happens for vc-diff

[-- Attachment #2: ~/bib/a.bib --]
[-- Type: application/octet-stream, Size: 1980 bytes --]

author	       = "Francesco Potortì and Sangjoon Park and Antonino Crivello and Filippo Palumbo
                  and Michele Girolami and Paolo Barsocchi and Soyeon Lee and Joaquín
                  Torres-Sospedra and Antonio Ramón Jimenez and Antoni Pérez-Navarro and Germán
                  M. Mendoza-Silva and Fernando Seco and Miguel Ortiz and Johan Perul and
                  Valerie Renaudin and Hyunwoong Kang and Soyoung Park and Jae Hong Lee and Chan
                  Gook Park and Jisu Ha and Jaeseung Han and Changjun Park and Keunhye Kim and
                  Yonghyun Lee and Seunghun Gye and Keumryeol Lee and Eunjee Kim and Jeongsik
                  Choi and Yang-Seok Choi and Shilpa Talwar and Seong Yun Cho and Boaz Ben-Moshe
                  and Alex Scherbakov and Leonid Antsfeld and Emilio Sansano-Sansano and Boris
                  Chidlovskii and Nikolai Kronenwett and Silvia Prophet and Yael Landau and
                  Revital Marbel and Lingxiang Zheng and Ao Peng and Zhichao Lin and Bang Wu and
                  Chengqi Ma and Stefan Poslad and David R. Selviah and Wei Wu and Zixiang Ma
                  and Wenchao Zhang and Dongyan Wei and Hong Yuan and Jun-Bang Jiang and
                  Shao-Yung Huang and Jing-Wen Liu and Kuan-Wu Su and Jenq-Shiou Leu and Kazuki
                  Nishiguchi and Walid Bousselham and Hideaki Uchiyama and Diego Thomas and
                  Atsushi Shimada and Rin-ichiro Taniguchi and Vicente Cortés and Tomás
                  Lungenstrass and Imran Ashraf and Chanseok Lee and Muhammad Usman Ali and
                  yeongjun im and Gunzung kim and jeongsook eom and Soojung Hur and Yongwan Park
                  and Miroslav Opiela and Adriano Moreira and Maria João Nicolau and Cristiano
                  Pendão and Ivo Silva and Filipe Meneses and António Costa and Jens Trogh and
                  David Plets and Ying-Ren Chien and Tzu-Yu Chang and Shih-Hau Fang and Yu Tsao",

[-- Attachment #3: ~/bib/a.bib~ --]
[-- Type: application/octet-stream, Size: 1981 bytes --]

AUTHOR         = "Francesco Potortì and Sangjoon Park and Antonino Crivello and Filippo Palumbo and Michele
                  Girolami and Paolo Barsocchi and Soyeon Lee and Joaquín Torres-Sospedra and
                  Antonio Ramón Jimenez and Antoni Pérez-Navarro and Germán M. Mendoza-Silva and
                  Fernando Seco and Miguel Ortiz and Johan Perul and Valerie Renaudin and
                  Hyunwoong Kang and Soyoung Park and Jae Hong Lee and Chan Gook Park and Jisu
                  Ha and JAESEUNG HAN and CHANGJUN PARK and KEUNHYE KIM and YONGHYUN LEE and
                  SEUNGHUN GYE and KEUMRYEOL LEE and EUNJEE KIM and Jeongsik Choi and Yang-Seok
                  Choi and Shilpa Talwar and Seong Yun Cho and Boaz Ben-Moshe and Alex
                  Scherbakov and Leonid Antsfeld and Emilio Sansano-Sansano and Boris
                  Chidlovskii and Nikolai Kronenwett and Silvia Prophet and Yael Landau and
                  Revital Marbel and Lingxiang Zheng and Ao Peng and Zhichao Lin and Bang Wu and
                  Chengqi Ma and Stefan Poslad and David R. Selviah and Wei Wu and Zixiang Ma
                  and Wenchao Zhang and Dongyan Wei and Hong Yuan and Jun-Bang Jiang and
                  Shao-Yung Huang and Jing-Wen Liu and Kuan-Wu Su and Jenq-Shiou Leu and Kazuki
                  Nishiguchi and Walid Bousselham and Hideaki Uchiyama and Diego Thomas and
                  Atsushi Shimada and Rin-ichiro Taniguchi and Vicente Cortés and Tomás
                  Lungenstrass and Imran Ashraf and Chanseok Lee and Muhammad Usman Ali and
                  yeongjun im and Gunzung kim and jeongsook eom and Soojung Hur and Yongwan Park
                  and Miroslav Opiela and Adriano Moreira and Maria João Nicolau and Cristiano
                  Pendão and Ivo Silva and Filipe Meneses and António Costa and Jens Trogh and
                  David Plets and Ying-Ren Chien and Tzu-Yu Chang and Shih-Hau Fang and Yu Tsao",