Merge pull request #716 from tmillr/fix-launchd-calendar-interval

fix(launchd): improve `StartCalendarInterval`

2 files changed, 127 insertions, 48 deletions

diff --git a/modules/launchd/launchd.nix b/modules/launchd/launchd.nix
index 9e13a3b..9eabf0a 100644
--- a/modules/launchd/launchd.nix
+++ b/modules/launchd/launchd.nix
@@ -2,6 +2,10 @@
 
 with lib;
 
+let
+  launchdTypes = import ./types.nix { inherit config lib; };
+in
+
 {
   options = {
     Label = mkOption {
@@ -344,55 +348,21 @@ with lib;
       default = null;
       example = [{ Hour = 2; Minute = 30; }];
       description = ''
-        This optional key causes the job to be started every calendar interval as specified. Missing arguments
-        are considered to be wildcard. The semantics are much like `crontab(5)`.  Unlike cron which skips job
-        invocations when the computer is asleep, launchd will start the job the next time the computer wakes
+        This optional key causes the job to be started every calendar interval as specified. The semantics are
+        much like {manpage}`crontab(5)`: Missing attributes are considered to be wildcard. Unlike cron which skips
+        job invocations when the computer is asleep, launchd will start the job the next time the computer wakes
         up.  If multiple intervals transpire before the computer is woken, those events will be coalesced into
-        one event upon wake from sleep.
-      '';
-      type = types.nullOr (types.listOf (types.submodule {
-        options = {
-          Minute = mkOption {
-            type = types.nullOr types.int;
-            default = null;
-            description = ''
-              The minute on which this job will be run.
-            '';
-          };
-
-          Hour = mkOption {
-            type = types.nullOr types.int;
-            default = null;
-            description = ''
-              The hour on which this job will be run.
-            '';
-          };
-
-          Day = mkOption {
-            type = types.nullOr types.int;
-            default = null;
-            description = ''
-              The day on which this job will be run.
-            '';
-          };
+        one event upon waking from sleep.
 
-          Weekday = mkOption {
-            type = types.nullOr types.int;
-            default = null;
-            description = ''
-              The weekday on which this job will be run (0 and 7 are Sunday).
-            '';
-          };
+        ::: {.important}
+        The list must not be empty and must not contain duplicate entries (attrsets which compare equally).
+        :::
 
-          Month = mkOption {
-            type = types.nullOr types.int;
-            default = null;
-            description = ''
-              The month on which this job will be run.
-            '';
-          };
-        };
-      }));
+        ::: {.caution}
+        Since missing attrs become wildcards, an empty attrset effectively means "every minute".
+        :::
+      '';
+      type = types.nullOr launchdTypes.StartCalendarInterval;
     };
 
     StandardInPath = mkOption {
@@ -895,6 +865,5 @@ with lib;
     };
   };
 
-  config = {
-  };
+  config = {};
 }
diff --git a/modules/launchd/types.nix b/modules/launchd/types.nix
new file mode 100644
index 0000000..38d7f20
--- /dev/null
+++ b/modules/launchd/types.nix
@@ -0,0 +1,110 @@
+{ lib, ... }:
+
+let
+  inherit (lib) imap1 types mkOption showOption optionDescriptionPhrase mergeDefinitions;
+  inherit (builtins) map filter length deepSeq throw toString concatLists;
+  inherit (lib.options) showDefs;
+  wildcardText = lib.literalMD "`*`";
+
+  /**
+    A type of list which does not allow duplicate elements. The base/inner
+    list type to use (e.g. `types.listOf` or `types.nonEmptyListOf`) is passed
+    via argument `listType`, which must be the final type and not a function.
+
+    NOTE: The extra check for duplicates is quadratic and strict, so use this
+    type sparingly and only:
+
+      * when needed, and
+      * when the list is expected to be recursively short (e.g. < 10 elements)
+        and shallow (i.e. strict evaluation of the list won't take too long)
+
+    The implementation of this function is similar to that of
+    `types.nonEmptyListOf`.
+  */
+  types'.uniqueList = listType: listType // {
+      description = "unique ${types.optionDescriptionPhrase (class: class == "noun") listType}";
+      substSubModules = m: types'.uniqueList (listType.substSubModules m);
+      # This has been taken from the implementation of `types.listOf`, but has
+      # been modified to throw on duplicates. This check cannot be done in the
+      # `check` fn as this check is deep/strict, and because `check` runs
+      # prior to merging.
+      merge = loc: defs:
+        let
+          # Each element of `dupes` is a list. When there are duplicates,
+          # later lists will be duplicates of earlier lists, so just throw on
+          # the first set of duplicates found so that we don't have duplicate
+          # error msgs.
+          checked = filter (li:
+            if length li > 1
+            then throw "The option `${showOption loc}' contains duplicate entries after merging:\n${showDefs li}"
+            else false) dupes;
+          dupes = map (def: filter (def': def'.value == def.value) merged) merged;
+          merged = filter (x: x ? value) (concatLists (imap1 (n: def:
+            imap1 (m: el:
+              let
+                inherit (def) file;
+                loc' = loc ++ ["[definition ${toString n}-entry ${toString m}]"];
+              in
+                (mergeDefinitions
+                  loc'
+                  listType.nestedTypes.elemType
+                  [{ inherit file; value = el; }]
+                ).optionalValue // {inherit loc' file;}
+            ) def.value
+          ) defs));
+      in
+        deepSeq checked (map (x: x.value) merged);
+    };
+in {
+  StartCalendarInterval = let
+    CalendarIntervalEntry = types.submodule {
+      options = {
+        Minute = mkOption {
+          type = types.nullOr (types.ints.between 0 59);
+          default = null;
+          defaultText = wildcardText;
+          description = ''
+            The minute on which this job will be run.
+          '';
+        };
+
+        Hour = mkOption {
+          type = types.nullOr (types.ints.between 0 23);
+          default = null;
+          defaultText = wildcardText;
+          description = ''
+            The hour on which this job will be run.
+          '';
+        };
+
+        Day = mkOption {
+          type = types.nullOr (types.ints.between 1 31);
+          default = null;
+          defaultText = wildcardText;
+          description = ''
+            The day on which this job will be run.
+          '';
+        };
+
+        Weekday = mkOption {
+          type = types.nullOr (types.ints.between 0 7);
+          default = null;
+          defaultText = wildcardText;
+          description = ''
+            The weekday on which this job will be run (0 and 7 are Sunday).
+          '';
+        };
+
+        Month = mkOption {
+          type = types.nullOr (types.ints.between 1 12);
+          default = null;
+          defaultText = wildcardText;
+          description = ''
+            The month on which this job will be run.
+          '';
+        };
+      };
+    };
+  in
+    types.either CalendarIntervalEntry (types'.uniqueList (types.nonEmptyListOf CalendarIntervalEntry));
+}