Add new custom variable 'projectile-cmd-hist-ignoredups'

Add new custom variable 'projectile-cmd-hist-ignoredups', which can be
used to tweak how duplicates are dealt with in projectile's command
history.  The custom variable is identical in behaviour to
'eshell-hist-ignoredups'.

Specifically, the existing default behavior is maintained with the
value of t, which means consecutive duplicates are ignored.  A value
of 'erase means only the last duplicate is kept, whilst a value of nil
means all duplicates are kept.

CHANGELOG.md

@@ -8,6 +8,7 @@
 * [#1870](https://github.com/bbatsov/projectile/pull/1870): Add package command for CMake projects.
 * [#1875](https://github.com/bbatsov/projectile/pull/1875): Add support for Sapling VCS.
 * [#1876](https://github.com/bbatsov/projectile/pull/1876): Add support for Jujutsu VCS.
+* [#1877](https://github.com/bbatsov/projectile/pull/1877): Add custom variable `projectile-cmd-hist-ignoredups`.
 
 ## 2.8.0 (2023-10-13)
 

doc/modules/ROOT/pages/projects.adoc

@@ -838,3 +838,9 @@ external command or an Emacs Lisp function:
 In addition caching of commands can be disabled by setting the variable
 `projectile-project-enable-cmd-caching` is to `nil`. This is useful for
 preset-based CMake projects.
+
+By default, Projectile will not add consecutive duplicate commands to its
+command history.  To alter this behaviour you can use `projectile-cmd-hist-ignoredups`.
+  The default value of `t` means consecutive duplicates are ignore, a value
+of `nil` means nothing is ignored, and a value of `'erase'` means only
+the last duplicate is kept in the command history.

projectile.el

@@ -874,6 +874,17 @@ If the value is nil, there is no limit to the opend buffers count."
   :type 'integer
   :package-version '(projectile . "2.2.0"))
 
+(defcustom projectile-cmd-hist-ignoredups t
+  "Controls when inputs are added to projectile's command history.
+
+A value of t means consecutive duplicates are ignored.
+A value of `erase' means only the last duplicate is kept.
+A value of nil means nothing is ignored."
+  :type '(choice (const :tag "Don't ignore anything" nil)
+                 (const :tag "Ignore consecutive duplicates" t)
+                 (const :tag "Only keep last duplicate" erase))
+  :package-version '(projectile . "2.9.0"))
+
 (defvar projectile-project-test-suffix nil
   "Use this variable to override the current project's test-suffix property.
 It takes precedence over the test-suffix for the project type when set.
@@ -5227,8 +5238,17 @@ The command actually run is returned."
     (when command-map
       (puthash default-directory command command-map)
       (let ((hist (projectile--get-command-history project-root)))
-        (unless (string= (car-safe (ring-elements hist)) command)
-          (ring-insert hist command))))
+        (cond
+         ((eq projectile-cmd-hist-ignoredups t)
+          (unless (string= (car-safe (ring-elements hist)) command)
+            (ring-insert hist command)))
+         ((eq projectile-cmd-hist-ignoredups 'erase)
+          (let ((idx (ring-member hist command)))
+            (while idx
+              (ring-remove hist idx)
+              (setq idx (ring-member hist command))))
+          (ring-insert hist command))
+         (t (ring-insert hist command)))))
     (when save-buffers
       (save-some-buffers (not compilation-ask-about-save)
                          (lambda ()

test/projectile-test.el

@@ -2138,25 +2138,43 @@ projectile-process-current-project-buffers-current to have similar behaviour"
       (expect 'async-shell-command :to-have-been-called-with "cmd" nil nil))))
 
 (describe "projectile--run-project-cmd"
-  (it "command history is not duplicated"
+
+  (before-each
     (spy-on 'projectile-run-compilation)
     (spy-on 'projectile-maybe-read-command :and-call-fake
             (lambda (arg default-cmd prompt) default-cmd))
     ;; Stops projectile--run-project-cmd from creating a new directory for
     ;; the compilation dir
-    (spy-on 'file-directory-p :and-return-value t)
+    (spy-on 'file-directory-p :and-return-value t))
+
+  (it "projectile-cmd-hist-ignoredups set to t"
+
     (let ((command-map (make-hash-table :test 'equal))
+          (projectile-cmd-hist-ignoredups t)
           ;; history is based on the project root, so we set it to a random
           ;; path to ensure there are no existing commands in history
           (projectile-project-root "/a/random/path"))
       (projectile--run-project-cmd "foo" command-map)
       (projectile--run-project-cmd "foo" command-map)
+      (projectile--run-project-cmd "bar" command-map)
+      (projectile--run-project-cmd "foo" command-map)
+      (expect 'projectile-run-compilation :to-have-been-called-times 4)
+      (expect (ring-elements
+               (projectile--get-command-history projectile-project-root))
+              :to-equal '("foo" "bar" "foo"))))
+
+  (it "projectile-cmd-hist-ignoredups set to erase"
+    (let ((command-map (make-hash-table :test 'equal))
+          (projectile-cmd-hist-ignoredups 'erase)
+          (projectile-project-root "/a/random/path"))
       (projectile--run-project-cmd "foo" command-map)
       (projectile--run-project-cmd "bar" command-map)
+      (projectile--run-project-cmd "foo" command-map)
+      (projectile--run-project-cmd "foo" command-map)
       (expect 'projectile-run-compilation :to-have-been-called-times 4)
       (expect (ring-elements
                (projectile--get-command-history projectile-project-root))
-              :to-equal '("bar" "foo")))))
+              :to-equal '("foo" "bar")))))
 
 (describe "projectile-test-prefix"
   :var ((mock-projectile-project-types