Discussed in
https://lists.gnu.org/archive/html/emacs-devel/2025-12/msg00903.html.
* lisp/progmodes/project.el (project-files) <vc>: Look up the
value of 'project-vc-ignores' inside DIR rather than project root.
This allows this variable to be applied in external dirs as well.
(project-ignores) <vc>: Do likewise.
(project--value-in-dir): Ensure that DIR has a trailing slash.
The caller might pass the value without slash if produced
differently.
* test/lisp/progmodes/project-tests.el
(project-vc-ignores-in-external-directory): New test.
(project-vc-supports-files-in-subdirectory): Update the test,
considering the subtle change in behavior: the directory DIR
directly includes a .dir-locals.el which sets project-vc-ignores,
which wasn't previously applied because it wasn't set in the root.
* test/lisp/progmodes/project-tests.el
(project-vc-supports-project-in-different-dir):
Account for difference in behavior when failing over to 'find'
(comments in bug#79809).
* lisp/progmodes/project.el (project-files):
Use 'file-in-directory-p' to dispatch to 'project--vc-list-files'
when listing subdirectory files too (bug#79809).
* test/lisp/progmodes/project-tests.el
(project-vc-extra-root-markers-supports-wildcards): End with a
check that we didn't cache a wrong value for parent (bug#73801).
* lisp/progmodes/project.el (project-find-regexp): Ensure the
DEFAULT-DIRECTORY is set correctly for the 'C-u' case (bug#70888).
* lisp/progmodes/project.el (project--files-in-directory):
Ensure that the DIR argument ends with a slash --
'dired-do-find-regexp' passes it differently, for example.
* lisp/progmodes/xref.el (xref--group-name-for-display): Ensure
the project-relative and absolute display modes work well for
groups with "relative" file names.
(xref--analyze, xref--add-log-current-defun): Change accordingly.
* test/lisp/progmodes/project-tests.el
(project-find-regexp-with-prefix): New test.
* test/lisp/progmodes/project-tests.el (project-find-regexp):
Add binding for project-list-file, to fix the test when running
in the terminal (reported on the mailing list).
* lisp/progmodes/project.el (project-files-relative-names):
New variable (bug#69233).
(project--files-in-directory): Honor it.
(project--vc-list-files): Here too.
(project-find-regexp): Use it to improve performance.
(project-or-external-find-regexp): Add a TODO.
(project-find-file): Use it here too.
(project--read-file-cpd-relative, project--read-file-absolute):
Try to handle file lists with absolute and relative files names.
(project-find-file-in): Set default-directory, so relative names
are interpreted correctly.
* lisp/progmodes/xref.el (xref-matches-in-files):
Consider that the first in FILES can be a relative file name.
* test/lisp/progmodes/project-tests.el (project-find-regexp):
New test.
* etc/NEWS: Mention it.
* lisp/progmodes/project.el (project-try-vc): When finding a
non-VC project root, still try to search for the containing
responsible VC backend, if any (bug#65704).
* lisp/progmodes/project.el (project-try-vc):
Use condition-case to catch 'file-missing' (bug#61107).
* test/lisp/progmodes/project-tests.el
(project-vc-nonexistent-directory-no-error): New test.
Essentialy revert commit 2389158a31, restoring the changes
and fixing the conflicts. Motivated by the problem brought up in
bug#59722 (behavior of project-find-files/regexp when switching
projects). We should find other ways to improve performance.
* lisp/progmodes/project.el
(project--value-in-dir, project--vc-merge-submodules-p): Restore.
(project-try-vc, project-files, project--vc-list-files)
(project-ignores, project-buffers): Use.
* test/lisp/progmodes/project-tests.el
(project-vc-supports-project-in-different-dir): New test.
* test/lisp/progmodes/project-resources/.dir-locals.el:
* test/lisp/progmodes/project-resources/foo:
* test/lisp/progmodes/project-resources/etc: New files.
* lisp/progmodes/project.el: Commentary update.
(project-vc, project-vc-include-untracked, project-vc-name):
Update docstrings. Rename 'VC project' to 'VC-aware project'.
(project-vc-extra-root-markers): New option (bug#41572).
(project-try-vc): Use it. Construct a single regexp from all and
validate it using the MATCH argument of 'directory-files'. Call
'locate-dominating-file' directly.
(project-ignores): Support VC-aware project instances with nil
value of VC backend.
* test/lisp/progmodes/project-tests.el (project-vc-recognizes-git)
(project-vc-extra-root-markers-supports-wildcards)
New tests.
(project-tests--this-file): New variable.
* lisp/progmodes/project.el (project--files-in-directory):
Pass "." as the DIR argument to 'find' because otherwise the ignore
expression can match the project root directory name, which we don't
want to happen (bug#50240). Fixup the resulting file names at the end
with concatenation.
Originally I thought it could lead to worse performance, but the
results show equal or slightly better timings.
* lisp/progmodes/xref.el (xref-matches-in-directory):
Apply a similar fix.
(xref--find-ignores-arguments): Use file-name-as-directory, so
that when passed "." replace-match still had the expected effect.
* test/lisp/progmodes/project-tests.el (project-ignores-bug-50240):
New test.
* test/lisp/progmodes/xref-tests.el
(xref-matches-in-directory-filters-with-ignores): New test.
* test/lisp/progmodes/project-tests.el (project-tests--trivial)
(project-root, project-ignores): New test project type.
(project-ignores): New unit test.
This is a useful abstraction, and saves a few levels of indentation in
the test body.
* test/lisp/progmodes/project-tests.el
(project-tests--with-temporary-directory): New helper macro.
(project/quoted-directory): Use it.
This is only a band-aid; it would be better to fix xref.el to work
with quoted filenames as well.
* lisp/progmodes/project.el (project--find-regexp-in-files): Unquote
filenames before passing them to 'xref-matches-in-files'.
* test/lisp/progmodes/project-tests.el (project/quoted-directory):
Also test 'project-find-regexp'.
* test/lisp/progmodes/project-tests.el (project/quoted-directory):
Skip if the 'find' program isn't available. The 'project-files'
function uses 'find' to obtain the list of project files.
* lisp/progmodes/project.el (project--files-in-directory): Unquote
directory name before passing it to 'find'.
(project--remote-file-names): Requote local filenames if the original
directory is quoted.
* test/lisp/progmodes/project-tests.el (project/quoted-directory): New
unit test.
