Configuration

In the typical style of Emacs, Projectile is extremely configurable. Pretty much every aspect of its behaviour can be tweaked or extended.

In this section we’ll go over some of the most common things you might want to fine-tune to make Projectile fit your workflow better.

Project indexing method

Projectile has three modes of operation - one is portable and is implemented in Emacs Lisp (therefore it’s native to Emacs and is known as the native indexing method) and the other two (hybrid and alien) rely on external commands like find, git, etc to obtain the list of files in a project.

The alien indexing method optimizes to the limit the speed of the hybrid indexing method. This means that Projectile will not do any processing or sorting of the files returned by the external commands and you’re going to get the maximum performance possible. This behaviour makes a lot of sense for most people, as they’d typically be putting ignores in their VCS config (e.g. .gitignore) and won’t care about any additional ignores/unignores/sorting that Projectile might also provide.

By default the alien method is used on all operating systems except Windows. Prior to Projectile 2.0 hybrid used to be the default (but to make things confusing hybrid used to be known as alien back then).

To force the use of native indexing in all operating systems:

(setq projectile-indexing-method 'native)

To force the use of hybrid indexing in all operating systems:

(setq projectile-indexing-method 'hybrid)

To force the use of alien indexing in all operating systems:

(setq projectile-indexing-method 'alien)

This can speed up Projectile in Windows significantly (especially on big projects). The disadvantage of this method is that it’s not well supported on Windows systems, as it requires setting up some Unix utilities there. If there’s problem, you can always use native indexing mode.

Alien indexing

The alien indexing works in a pretty simple manner - it simply shells out to a command that returns the list of files within a project. For version-controlled projects by default Projectile will use the VCS itself to obtain the list of files. As an example, here is the command that Projectile uses for Git projects:

git ls-files -zco --exclude-standard

For every supported VCS there’s a matching Projectile defcustom holding the command to invoke for it (e.g. projectile-git-command, projectile-hg-command, etc).

If you ever decide to tweak those keep in mind that the command should always be returning the list of files relative to the project root and the resulting file list should be 0-delimited (as opposed to newline delimited).

For non-VCS projects Projectile will invoke whatever is in projectile-generic-command. By default that’s:

find . -type f -print0
It’s a great idea to install fd which is much faster than find. If fd is found, projectile will use as a replacement for find.

Sorting

You can choose how Projectile sorts files by customizing projectile-sort-order.

Note that if Alien indexing is set, files are not sorted by Projectile at all.

The default is to not sort files:

(setq projectile-sort-order 'default)

To sort files by recently opened:

(setq projectile-sort-order 'recentf)

To sort files by recently active buffers and then recently opened files:

(setq projectile-sort-order 'recently-active)

To sort files by modification time (mtime):

(setq projectile-sort-order 'modification-time)

To sort files by access time (atime):

(setq projectile-sort-order 'access-time)

Caching

Project files

Since indexing a big project is not exactly quick (especially in Emacs Lisp), Projectile supports caching of the project’s files. The caching is enabled by default whenever native indexing is enabled.

To enable caching unconditionally use this snippet of code:

(setq projectile-enable-caching t)

At this point you can try out a Projectile command such as s-p f (M-x projectile-find-file RET).

Running C-u s-p f will invalidate the cache prior to prompting you for a file to jump to.

Pressing s-p z will add the currently visited file to the cache for current project. Generally files created outside Emacs will be added to the cache automatically the first time you open them.

The project cache is persistent and will be preserved during Emacs restarts.

You can purge an individual file from the cache with M-x projectile-purge-file-from-cache or an entire directory with M-x projectile-purge-dir-from-cache.

File exists cache

Projectile does many file existence checks since that is how it identifies a project root. Normally this is fine, however in some situations the file system speed is much slower than usual and can make emacs "freeze" for extended periods of time when opening files and browsing directories.

The most common example would be interfacing with remote systems using TRAMP/ssh. By default all remote file existence checks are cached

To disable remote file exists cache that use this snippet of code:

(setq projectile-file-exists-remote-cache-expire nil)

To change the remote file exists cache expire to 10 minutes use this snippet of code:

(setq projectile-file-exists-remote-cache-expire (* 10 60))

You can also enable the cache for local file systems, that is normally not needed but possible:

(setq projectile-file-exists-local-cache-expire (* 5 60))

Using Projectile Commands Outside of Projects Directories

Normally, you’d be using Projectile’s commands from within some project directory. If, however, you invoke a command outside of a project, by default you’ll be prompted for a project to switch to. That behavior is controlled by projectile-require-project-root. You can make Projectile simply raise an error outside of Project folders like this:

(setq projectile-require-project-root t)

If you want Projectile to be usable in every directory (even without the presence of project file):

(setq projectile-require-project-root nil)

With this setting if you invoke Projectile outside of a project, the current directory will be considered by Projectile the project root.

This might not be a great idea if you start Projectile in your home folder for instance. :-)

Switching projects

By default, projectile does not include the current project in the list when switching projects. If you want to include the current project, customize variable projectile-current-project-on-switch.

When running projectile-switch-project (s-p p) and projectile-switch-open-project (s-p q) Projectile invokes the command specified in projectile-switch-project-action (by default it is projectile-find-file).

Invoking the command with a prefix argument (C-u s-p p or C-u s-p q) will trigger the Projectile Commander, which gives you quick access to most common commands you might want to invoke on a project.

Depending on your personal workflow and habits, you may prefer to alter the value of projectile-switch-project-action:

projectile-find-file

This is the default.

With this setting, once you have selected your project via Projectile’s completion system (see below), you will remain in the completion system to select a file to visit. projectile-find-file is capable of retrieving files in all sub-projects under the project root, such as Git submodules. Currently, only Git is supported. Support for other VCS will be added in the future.

projectile-commander

This is the recommended option for people who find themselves often needing to invoke a different action on project switch.

With this setting, after selecting a project to switch to, you’ll be prompted to specify the action to take with a 1-character mnemonic.

Keybinding

Description

?

Commander help buffer.

D

Open project root in dired.

R

Regenerate the project’s etags/gtags.

T

Find test file in project.

V

Browse dirty projects

a

Run ag on project.

b

Switch to project buffer.

d

Find directory in project.

e

Find recently visited file in project.

f

Find file in project.

g

Run grep on project.

j

Find tag in project.

k

Kill all project buffers.

o

Run multi-occur on project buffers.

r

Replace a string in the project.

s

Switch project.

v

Open project root in vc-dir or magit.

projectile-find-file-in-known-projects

Similar to projectile-find-file but lists all files in all known projects. Since the total number of files could be huge, it is beneficial to enable caching for subsequent usages.

projectile-find-file-dwim

If point is on a filepath, Projectile first tries to search for that file in project:

  • If it finds just a file, it switches to that file instantly. This works even if the filename is incomplete, but there’s only a single file in the current project that matches the filename at point. For example, if there’s only a single file named "projectile/projectile.el" but the current filename is "projectile/proj" (incomplete), projectile-find-file still switches to "projectile/projectile.el" immediately because this is the only filename that matches.

  • If it finds a list of files, the list is displayed for selecting. A list of files is displayed when a filename appears more than one in the project or the filename at point is a prefix of more than two files in a project. For example, if `projectile-find-file' is executed on a filepath like "projectile/", it lists the content of that directory. If it is executed on a partial filename like "projectile/a", a list of files with character 'a' in that directory is presented.

  • If it finds nothing, display a list of all files in project for selecting.

projectile-dired

(setq projectile-switch-project-action #'projectile-dired)

With this setting, once you have selected your project, the top-level directory of the project is immediately opened for you in a dired buffer.

projectile-find-dir

(setq projectile-switch-project-action #'projectile-find-dir)

With this setting, once you have selected your project, you will remain in Projectile’s completion system to select a sub-directory of your project, and then that sub-directory is opened for you in a dired buffer. If you use this setting, then you will probably also want to set

(setq projectile-find-dir-includes-top-level t)

in order to allow for the occasions where you want to select the top-level directory.

Completion Options

Auto (default)

By default Projectile detects the completion system in use, based on the mode variables ido-mode, ivy-mode and helm-mode. If none of those is activated, the default completion system is used.

Unless for some reason you want to use a different completion system for Projetile than for the rest of Emacs, you’ll probably don’t want to select a particular completion system manually.

Basic (Emacs’s default)

If you don’t like ido and ivy you can use regular completion (based on completing-read):

(setq projectile-completion-system 'default)
You might want to combine default completion with icomplete-mode for optimum results. Emacs 27 added fido-mode to icomplete.

If you are using fido-mode, Projectile will use the default completion system. The same holds for selectrum which also relies on the default completion system.

Ido

The ido completion system is extremely popular and it is built into Emacs.

(setq projectile-completion-system 'ido)

As noted above, Projectile will auto-detect ido-mode if enabled, so the above configuration is not needed most of the time.

As already noted above if you’re going to use the ido completion it’s extremely highly recommended that you install the optional flx-ido package, which provides a much more powerful alternative to ido's built-in flex matching.

Another completion option is ivy:

(setq projectile-completion-system 'ivy)

As noted above, Projectile will auto-detect ivy-mode if enabled, so the above configuration is not needed most of the time.

Custom Completion Function

You can also set projectile-completion-system to a function:

(setq projectile-completion-system #'my-custom-completion-fn)
(setq projectile-completion-system
      (lambda (prompt choices)
        ;; ...
        ))

An example of a custom completion function is this one, which only show the file name (not including path) and if the file selected is not unique, another completion with names relative to project root appears.

Project-specific Compilation Buffers

This affects all commands built on top of projectile—​run-project-cmd like:

  • projectile-configure-project

  • projectile-run-project

  • projectile-test-project

  • projectile-install-project

  • projectile-package-project

Normally, the buffers created by those commands would be shared (overwritten) between projects, but it’s also possible to make the compilation buffer names project-specific. Currently, this requires that the user explicitly set:

(setq compilation-buffer-name-function
      #'projectile-compilation-buffer-name)
(setq compilation-save-buffers-predicate
      #'projectile-current-project-buffer-p)

Both of these degrade properly when not inside a project.

Regenerate tags

To be able to regenerate a project’s tags via projectile-tags-command, you should install and add to the PATH Exuberant Ctags instead of a plain ctags, which ships with Emacs distribution.

Idle Timer

Projectile can be configured to run the hook projectile-idle-timer-hook every time Emacs is in a project and has been idle for projectile-idle-timer-seconds seconds (default is 30 seconds). To enable this feature, run:

M-x customize-group RET projectile RET

and set projectile-enable-idle-timer to non-nil. By default, projectile-idle-timer-hook runs projectile-regenerate-tags. Add additional functions to the hook using add-hook:

(add-hook 'projectile-idle-timer-hook #'my-projectile-idle-timer-function)

Mode line indicator

By default the minor mode indicator of Projectile appears in the form " Projectile[ProjectName:ProjectType]". This is configurable via several custom variables:

  • projectile-mode-line-prefix (by default " Projectile") controls the static part of the mode-line

  • projectile-dynamic-mode-line (by default t) controls whether to display the project name & type part of the mode-line

  • projectile-mode-line-function (by default projectile-default-mode-line) controls the actual function to be invoked to generate the mode-line. If you’d like to show different info you should supply a custom function to replace the default, for example (setq projectile-mode-line-function '(lambda () (format " Proj[%s]" (projectile-project-name))))

The project name & type will not appear when editing remote files (via TRAMP), as recalculating the project name is a fairly slow operation there and would slow down a bit opening the files. They will also not appear for non-file buffers, as they get updated via find-file-hook.

Project-type-specific Configuration

CMake

Projectile supports CMake presets. Preset support is disabled by default, but can be enabled by setting projectile-enable-cmake-presets to non-nil. With preset-support enabled Projectile will parse the preset files and present the command-specific presets when executing a lifecycle command. In addition a no preset option is included for entering the command manually.

Preset support requires a CMake version that supports preset and for json-parse-buffer to be available.