**As** an OpenProject user
**I want** to calculate the work package start and end dates based on the duration
**so** that I only have to set the duration.

# **Acceptance criteria:**

The duration feature affects a range of views and modules:

### Work package attributes and date picker

* In the date picker modal there is a text field `duration`.
* When the user enters a duration and at least one of the dates is set, the other is derived:
* The contrary is also true: when a user enters dates, the duration is derived.
* The duration represents the amount of days between the start and the finish date (inclusive):
* Monday to Tuesday: 2 days
* Monday to Monday (same day): 1 day
* Duration is always in full days (never floating point values).
* Once configuring non-working days is implemented (<mention class="mention" data-id="18416" data-type="work_package" data-text="#18416">#18416</mention>), these non-working days are _skipped_ _over_ and do not count towards the total duration:
* Friday to Monday: 2 days _(Saturday and Sunday are skipped over)_
* The user is able to override configured non-working days per work package by choosing to include them via the date-picker (more details on [this feature describing the datepicker](https://community.openproject.org/work_packages/41341):  <mention class="mention" data-id="41341" data-type="work_package" data-text="#41341">#41341</mention>).
* Begin of the deletion When an administrator changes non-working days via instance admin settings (adds or removes a working day), this will affect dates of scheduled work packages. If non-working days are added or removed for the instance by an admin, the _duration_ is preserved, which might mean the start and finish dates might change:
* The user is warned that changing which days are considered working days (eg. adding/removing Friday as a non-working day) will affect the dates of all work packages of all project in the the instance, and that there is no preview of what these changes will be.
* This warning is specified in the feature concerning the new &quot;Working days&quot; admin settings page (<mention class="mention" data-id="42316" data-type="work_package" data-text="#42316">#42316</mention>).
* If a work package included a date that is now a non-working day, the finish date moves to the corresponding number of now-excluded days to maintain duration.
* If a work package was scheduled to start on a date it is now a non-working day, the start date moves to the earliest working day in the future (and the finish date changes by consequence).
* Even if a work package does not span or included a day that is now a non-working day, it might nevertheless be affected because of relations.
* Eg. A preceeding work package has pushed its dates forwards or backwards such that it now spans a non-working day.End of the deletion In Begin of the deletion this case, the work package will be pushed/pulled as it does today, and the work package will be rescheduled as any other work package (it adapt it start and finish dates to maintain duration).
* The journal will be displayed to the user for _affected_ work packages only, attributed to the author (admin who make the change), like so:
* For changes to the work week:
* _**Working days** changed (Friday is now non-working) by Jean-Cérien._
* _**Start date** changed from {old date} to {new date}._
* _**Finish date** changed from {old date} to {new date}._
* <mention class="mention" data-id="87" data-type="user" data-text="@Jens Ulferts">@Jens Ulferts</mention>: Does this phrase work for change in working days? To what kind of information do we have access?
* ~~For changes to individual non-working days: &quot;Jean Cérien has configured 2022-10-10 as a non-working day. Duration changed from 2 to 3 days.&quot;~~ (descoped)
* ~~The only exception is if a start/end date of a work package falls on a date that is now configured to be a non-working day; in this case, the duration is unchanged and the &quot;Include non-working days&quot; option is checked to allow the the duration to be preserved.~~
* InEnd of the deletion all cases, the duration is consistent with the start and the finish date. Updating dates will update duration, and updating duration will update dates.
* It will not possible, for example, to specify a duration of 8 days for a task that starts and finishes the same week. Begin of the deletion
* For a work package that has a start date, a finish date and thus also a duration, removing one of the dates (start or finish) will also remove the duration
* Of course, clicking on a second date (or manually adding a second date) will add a new duration and the duration will be changed and all three fields will now be complete.
* This also means that it is not possible to conserve duration when deleting dates, since deleting one date will also delete duration. To remove start and finish dates from a work package that already has these fields but keep the duration, the duration will then have to be re-entered after removing the dates.
* It is not possible to remove duration from a field that has start and end dates. (For example, if the user clears the text field manually, the value will automatically be re-entered on blur based on start and finish dates).End of the deletion
* The duration and the position of the start and finish dates can not be configured via the form configuration. They are always present at the same place within the work package show page and form.
* This will be later updated with <mention class="mention" data-id="40539" data-type="work_package" data-text="#40539">#40539</mention>.
* New work packages have an empty (not set) default duration.
* Certain date/duration information is derived (third value when two fields are filled).
* Setting start _and_ end dates automatically sets duration.
* Setting only one of the dates does not automatically set duration (unable to derive).
* Setting only one of the dates plus the duration sets the other date (derived).
* It is possible to have _no attributes_, _only one attribute_ or all three. It is not possible to have just two (since the third will be derived from the other two).
* Concretely, these are **possible**:
* No start date, no finish date; no duration -- is possible.
* No start date; no finish dates; duration set -- is possible
* Start date specified; no finish date; no duration -- is possible.
* No start date; finish date specified; no duration -- is possible
* But these are **not possible**:
* Start date specified; no finish date; duration specified -- is _not possible_. (End date is derived)
* No start date; finish date specified; duration specified -- is _not possible_. (Start date is derived)
* Start date specified; no finish date; duration specified -- is _not possible_. (End date is derived)
* No start date; finish date specified; duration specified -- is _not possible_. (Start date is derived). Begin of the insertion

### Single-date work packages (milestones)

End of the insertion Begin of the deletion
End of the deletion * Milestone-typed work packages don&#39;t have a duration field (see <mention class="mention" data-id="41341" data-type="work_package" data-text="#41341">#41341</mention> for details).
* In 12.2 and 12.3, they will internally have a value of 1 day and behave as it does today.
* This means that when a milestone has a follows/precedes relation with a work package, there will still be a minimum gap of a day between them.
* GANTT chart: a milestone is still displayed as a diamond.
* Team planner: a milestone spans 1 day.
* Uses the &quot;simple&quot; date picker, with just one date field and no duration. Begin of the deletion
* Concerning following/preceeding relations:
* If a &quot;following&quot; or &quot;preceding&quot; relationship is added to a work package without dates or duration, this will not automatically give it a duration.
* When adding a relationship leads to a derivation of a date (start or finish), the duration is still not set (empty), since only one date is available.End of the deletion

### Manual scheduling and non-working days

* Scheduling modes (manual/automatic scheduling) are independent of non-working days (and thus constrained by it)
* A work package that is manually scheduled does not automatically also include non-working days; in other words, a manually scheduled work package ignores relations (parent/child, following/preceeding) but nevertheless skips weekends.
* **Eg.** A manually scheduled work package that starts on Thursday, Feb 11, 20211 and has a duration of 4 days still ends on Tuesday, Feb 16, 2011.
* Dragging a manually-scheduled work package (that does not already have the option to including non-working days enabled) into a non-working day in the GANTT or the team planner does is not possible.
* The same goes for dragging the edges  into a non-working day; this is also not possible unless the option to include non-working days is already enabled.
* Should the user want a manually scheduled work package to start on a Saturday (for example), they can do so by enabline the option to include non-working days for that work package and selecting the desired date (that is normally non-working).

### Begin of the insertionDuration and work package relations

* If children only have duration (no dates), then the parent cannot have start/end dates, nor duration.
* The duration of a parent is _à minima_ a sum of the duration of the children, but this cannot be inferred, since there can be a gap between children. Therefore, duration will be left plank.
* For parent work packages, &quot;Include weekends&quot; is automatically enabled if _any_ of the children have this enabled.
* This is notably important when children with the earliest start date and the latest finish date (that define the start and finish date for the parent) have this option enabled. But the rule is general; even a &quot;middle&quot; child that does not normally affect the start and finish date that is set to &quot;include weekends&quot; will apply this setting to the parent.
* If a &quot;following&quot; or &quot;preceding&quot; relationship is added to a work package without dates or duration, this will not automatically give it a duration.
* When adding a relationship leads to a derivation of one date (start or finish), the duration is still not set (empty), since only one date is available.
* Current behaviour is maintained for date changes to a work package as a result of the date change of a preceeding/following work package. Some precisions: 
* If a date change is a result of enabling &quot;include weekend&quot; on a preceeding work package, the start date of the following work package can move backwards in time (earlier). Its duration and delay are conserved, as it is today.
* If a date change is a result of disabling &quot;include weekend&quot; on a preceeding work package, the start date of the following work package can move forwards in time (later). Its duration and delay are conserved, as it is today.
* The same rules apply to a preceeding work package when a date change is required by the modification of a following work package.

###End of the insertion Work package table view

* In the work packages list there is a column &quot;duration&quot;. When clicking on this, the date modal with the date picker is opened, with the focus on the duration field.
* Ideally the value is displayed with the value followed by the unit as a full word &quot;days&quot; (and &quot;jours&quot;, &quot;Tage&quot; and so forth) handling pluralisation correctly. If we don&#39;t already have a system in place to do that, we can fall back on &quot;d&quot; (and &quot;j&quot;, and &quot;t&quot; and so forth)
* Filtering by duration is possible.
* Sorting by duration is possible.

### GANTT chart

* For work packages without start/finish dates but _with_ duration, the width of a &quot;strip&quot; representing such a work package on hover on a GANTT view has a width that is relative to its total duration (on drag over GANTT).
* &quot;Relative&quot; because width depends on the zoom level of the GANTT chart.
* On click, end date is calculated based on the the start date selected.
* If the duration is very long one (finish date is outside of current view), the user will first have to click to commit, and then zoom out or scroll to view the finish date.
* If the user modifies a work package via the drag handles on the left/right edges of the strips the in Gantt chart, both the start/finish date as well as the duration are altered in lockstep, based on which side is dragged.
* If non-working are included for that work package (via the date-picker), they will need to be taken into account in the GANTT too (for example, the work package should span the weekend if the weekend is included).
* For how work packages in GANTT view are affected by non-working days, refer to <mention class="mention" data-id="43637" data-type="work_package" data-text="#43637">#43637</mention>

### Team planner

* For work packages without start/finish dates but _with_ duration:
* they are not visible on the Team planner calendar until a date is specified (they can of course be accessed using the &quot;Add Existing&quot; function)
* the width of a card that is dragged onto the team planner (from the left-hand &quot;Add Existing&quot; panel, for example) is relative to the total duration of that work package (within the limits of the viewport, of course).
* Once dragged, the start date is set and therefore the finish date is also derived.
* If the user modifies a work package via the drag handles on the left/right edges of the cards on the Team planner, both the start/finish date as well as the duration are altered in lockstep.
* For how work packages in the team planner are affected by non-working days, refer to <mention class="mention" data-id="43638" data-type="work_package" data-text="#43638">#43638</mention>.

Begin of the insertion### Activity logEnd of the insertion Begin of the deletion # Open questions answeredEnd of the deletion

* Begin of the deletion Visuals for the rework and repositioning of the dates &amp; duration fields in a work package are handled separately (<mention class="mention" data-id="40539" data-type="work_package" data-text="#40539">#40539</mention>)
* Inheritance of the duration between a work package and its children:
* As is the case today, the parent&#39;s start and end dates dates (and thus also duration) are derived from the children.
* It is nevertheless possible to enable manual scheduling, in which case the user has full agency to change the dates as they please (on working days, or any day if non-working days are included); however, the dates of children will no longer affect the parent, and will no longer be constrainted by them.
* End of the deletion If Begin of the deletion children only have duration, then the parent cannot have start/end dates, nor duration.
* The duration of a parent is _à minima_ a sum of the duration of the children, but this cannot be inferred, since there can be a gap between children. Therefore, this information will be left blank,
* How will the duration be reflected in the activity, assuming that duration should be part of the activity? (<mention class="mention" data-id="42924" data-type="work_package" data-text="#42924">#42924</mention> )
* IfEnd of the deletion dates are changed (which affects duration), or duration is changed (which affects dates), then that will considered both a date and duration change: Begin of the insertion
End of the insertion Begin of the deletion
End of the deletion * Begin of the insertion**&quot;FinishEnd of the insertion Begin of the deletion **FinishEnd of the deletion date** changed from {date} to Begin of the insertion{date}&quot;
End of the insertion Begin of the deletion {date}.
End of the deletion * Begin of the insertion**&quot;Duration**End of the insertion Begin of the deletion **Duration**End of the deletion changed to {n} Begin of the insertiondays&quot;
End of the insertion Begin of the deletion days.
End of the deletion * For work packages with only duration, then the duration will be an independent journal entry: Begin of the insertion
End of the insertion Begin of the deletion
End of the deletion * Begin of the insertion**&quot;Duration**End of the insertion Begin of the deletion **Duration**End of the deletion changed to {n} Begin of the insertiondays&quot;End of the insertion Begin of the deletion days.End of the deletion

Begin of the insertion### ChangeEnd of the insertion Begin of the deletion # Still open questions

**Duration/NWDEnd of the deletion in Begin of the insertionset of working days (instance admin) End of the insertion Begin of the deletion parents**End of the deletion

Begin of the insertion* When an administrator changes non-working days via instance admin settings (adds or removesEnd of the insertion Begin of the deletion There&#39;sEnd of the deletion a Begin of the insertionworking day), this will affect datesEnd of the insertion Begin of the deletion particular challenge in determining the duration (and sometimes, start/finish dates)End of the deletion of Begin of the insertionscheduledEnd of the insertion Begin of the deletion parentEnd of the deletion work Begin of the insertionpackages. IfEnd of the insertion Begin of the deletion packages when some children includeEnd of the deletion non-working days Begin of the insertionare added or removed for the instance by an admin, the _duration_ is preserved, which might mean the startEnd of the insertion and Begin of the insertionfinish dates might change:End of the insertion Begin of the deletion some don&#39;t. Take this case:

* A parent has two children:End of the deletion
* Begin of the insertionThe user is warned that changing which days are considered working days (eg. adding/removing Friday as a non-working day) will affect the dates of all work packages of all project in the the instance, and that there is no preview of what these changes will be.
End of the insertion Begin of the deletion Task 1: Thursday 4 – Tuesday 9 (4 days, NWD not included)
End of the deletion * Begin of the insertionThis warning is specified in the feature concerning the new &quot;Working days&quot; admin settings page (<mention class="mention" data-id="42316" data-type="work_package" data-text="#42316">#42316</mention>).End of the insertion Begin of the deletion Task 2: Wednesday 10 – Saturday 13 (4 days, NWD included)

Questions:

* Does this parent cover:End of the deletion
* Begin of the deletion Thursday 4 – Friday 12 (NWD not included, duration: 7) or
* Thursday 4 – Saturday 13 (NWD included, duration: 10 days)?
* End of the deletion If Begin of the insertiona work package included a dateEnd of the insertion Begin of the deletion the former, this would meanEnd of the deletion that Begin of the insertionis now a non-working day,End of the insertion Begin of the deletion children with NWDs are an exception and that they don&#39;t affectEnd of the deletion the Begin of the insertionfinish date moves to the corresponding number of now-excluded days to maintain duration.End of the insertion Begin of the deletion parents.End of the deletion
* Begin of the insertionIf a work package was scheduled to startEnd of the insertion Begin of the deletion In this case, should we display the this differenceEnd of the deletion on Begin of the insertionaEnd of the insertion Begin of the deletion the GANTT view  (the finshEnd of the deletion date Begin of the insertionit is now a non-working day,End of the insertion Begin of the deletion of Task 2 that ends beyondEnd of the deletion the Begin of the insertionstartEnd of the insertion Begin of the deletion finishEnd of the deletion date Begin of the insertionmoves toEnd of the insertion Begin of the deletion ofEnd of the deletion the Begin of the insertionearliest working dayEnd of the insertion Begin of the deletion parent)End of the deletion in the Begin of the insertionfuture (and the finish date changesEnd of the insertion Begin of the deletion same way we show descrepencies causedEnd of the deletion by Begin of the insertionconsequence).
* Even if a work package does not span or included a dayEnd of the insertion Begin of the deletion manual scheduling? (LinesEnd of the deletion that Begin of the insertionis now a non-working day, it might nevertheless be affected because of relations.
End of the insertion Begin of the deletion can extend from the actual WP block).
End of the deletion * Begin of the insertionEg. A preceeding work package has pushed its dates forwards or backwards suchEnd of the insertion Begin of the deletion If the second, this meansEnd of the deletion that Begin of the insertionit now spans a non-working day. In this case,End of the insertion Begin of the deletion any children including non-workging days will automatically meanEnd of the deletion the Begin of the insertionwork packageEnd of the insertion Begin of the deletion parentsEnd of the deletion will Begin of the insertionbe pushed/pulled as it does today, andEnd of the insertion Begin of the deletion include non-working days (whilst still takingEnd of the deletion the Begin of the insertionwork package will be rescheduled as any other work package (it adapt itEnd of the insertion start and finish Begin of the insertiondates to maintain duration).
* The journalEnd of the insertion Begin of the deletion date of the earlier and latest child, the durationEnd of the deletion will Begin of the deletion thenEnd of the deletion be Begin of the insertiondisplayedEnd of the insertion Begin of the deletion affectedEnd of the deletion to Begin of the insertionthe user for _affected_ work packages only, attributed to the author (admin who make the change), like so:
End of the insertion Begin of the deletion count all non-working days in between):
End of the deletion * Begin of the insertionFor changes to the work week:
* &quot;_**Working days** changed (Friday is now non-working) by Jean-Cérien_&quot;
* &quot;_**Start date** changed from {old date} to {new date}_&quot;
* &quot;_**Finish date** changed from {old date} to {new date}_&quot;
* <mention class="mention" data-id="87" data-type="user" data-text="@Jens Ulferts">@Jens Ulferts</mention>: Does this phrase work for change in working days? To what kind of information do weEnd of the insertion Begin of the deletion This wouldEnd of the deletion have Begin of the insertionaccess?
* ~~For changesEnd of the insertion to Begin of the insertionindividual non-working days: &quot;Jean Cérien has configured 2022-10-10 as a non-working day. Duration changed from 2 to 3 days.&quot;~~ (descoped)
* ~~The only exception isEnd of the insertion Begin of the deletion be evenEnd of the deletion if Begin of the insertiona start/end date of a work package falls on a dateEnd of the insertion that Begin of the deletion the only child including non-working daysEnd of the deletion is Begin of the insertionnow configured to be a non-working day;End of the insertion in Begin of the insertionthis case,End of the insertion Begin of the deletion between and does not normally affectEnd of the deletion the Begin of the insertionduration is unchangedEnd of the insertion Begin of the deletion startEnd of the deletion and Begin of the insertionthe &quot;Include non-working days&quot; option is checked to allow the the duration to be preserved.~~End of the insertion Begin of the deletion finish date of parents.End of the deletion

# Visuals

#### **The new date picker drop modal**

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/37929/content">

Additional visuals for the date picker are in the related work package describing the date picker <mention class="mention" data-id="41341" data-type="work_package" data-text="#41341">#41341</mention>.

#### Duration column in a work package table view

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/36703/content">

#### The date picker drop modal in the work package table view (duration)

Note that the &quot;duration&quot; field is focused when opening the drop modal by clicking on a duration value.

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/37930/content">

#### The duration column can also be used to adjust the GANTT chart

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/36705/content">

# Seed Data

**Static queries in section &quot;Default data&quot;:**

* Gantt chart: Add duration column after column finish date:

**Queries in section favorite views**

* Project plan (Query ID 1): Add duration column after column finish date
* Project plan (Query ID 14): Add duration column after column finish date

# Full screen view

* Currently the status selection is below the subject at the same position for all work package types.
* We also move the dates and the curation to this area (visuals tbd).
* For milestones there is no duration by definition.

# Out-of-Scope

* Consider weekends and holidays (for this ticket, will normally already have been dealt with by <mention class="mention" data-id="18416" data-type="work_package" data-text="#18416">#18416</mention>)
* Summing duration _(need clarification)_
* Grouping by durations _(need clarification)_