acquire: Use priority queues and a 3 stage pipeline design

[apt.git] / doc / external-dependency-solver-protocol.txt

diff --git a/doc/external-dependency-solver-protocol.txt b/doc/external-dependency-solver-protocol.txt
index e2bd95866f303abea02de859fbdff9202a7d5672..56689066539e71c1e3218c0aeaf081bdbb17e88b 100644 (file)
--- a/doc/external-dependency-solver-protocol.txt
+++ b/doc/external-dependency-solver-protocol.txt
@@ -70,6 +70,11 @@ configuration documentation for more, and more up to date, information.
   of the solver you are using if and what is supported as a value here.
   Defaults to the empty string.
 
   of the solver you are using if and what is supported as a value here.
   Defaults to the empty string.
 

+- **APT::Solver::RunAsUser**: if APT itself is run as root it will
+  change to this user before executing the solver. Defaults to the value
+  of APT::Sandbox::User, which itself defaults to `_apt`. Can be
+  disabled by set this option to `root`.
+

 The options **Strict-Pinning** and **Preferences** can also be set for
 a specific solver only via **APT::Solver::NAME::Strict-Pinning** and
 **APT::Solver::NAME::Preferences** respectively where `NAME` is the name
 The options **Strict-Pinning** and **Preferences** can also be set for
 a specific solver only via **APT::Solver::NAME::Strict-Pinning** and
 **APT::Solver::NAME::Preferences** respectively where `NAME` is the name


@@ -156,17 +161,26 @@ The following **action fields** are supported in request stanzas:
   Install. This field denotes a list of packages that the user wants to
   remove, usually via APT `remove` or `purge` requests.
 
   Install. This field denotes a list of packages that the user wants to
   remove, usually via APT `remove` or `purge` requests.
 

-- **Upgrade:** (optional, defaults to `no`). Allowed values: `yes`,
+- **Upgrade-All:** (optional, defaults to `no`). Allowed values `yes`,

   `no`. When set to `yes`, an upgrade of all installed packages has been
   `no`. When set to `yes`, an upgrade of all installed packages has been

-  requested, usually via an APT `upgrade` request.
-
-- **Dist-Upgrade:** (optional, defaults to `no`). Allowed values: `yes`,
-  `no`. Same as Upgrade, but for APT `dist-upgrade` requests.
+  requested, usually via an upgrade command like 'apt full-upgrade'.

 
 - **Autoremove:** (optional, defaults to `no`). Allowed values: `yes`,
   `no`. When set to `yes`, a clean up of unused automatically installed
   packages has been requested, usually via an APT `autoremove` request.
 
 
 - **Autoremove:** (optional, defaults to `no`). Allowed values: `yes`,
   `no`. When set to `yes`, a clean up of unused automatically installed
   packages has been requested, usually via an APT `autoremove` request.
 

+- **Upgrade:** (deprecated, optional, defaults to `no`). Allowed values:
+  `yes`, `no`. When set to `yes`, an upgrade of all installed packages
+  has been requested, usually via an APT `upgrade` request. A value of
+  `yes` is equivalent to the fields `Upgrade-All`,
+  `Forbid-New-Install`and `Forbid-Remove` all set to `yes`.
+
+- **Dist-Upgrade:** (deprecated, optional, defaults to `no`). Allowed
+  values: `yes`, `no`. Same as Upgrade, but for APT `dist-upgrade`
+  requests. A value of `yes` is equivalent to the field `Upgrade-All`
+  set to `yes` and the fields `Forbid-New-Install`and `Forbid-Remove`
+  set to `no`.
+

 The following **preference fields** are supported in request stanzas:
 
 - **Strict-Pinning:** (optional, defaults to `yes`). Allowed values:
 The following **preference fields** are supported in request stanzas:
 
 - **Strict-Pinning:** (optional, defaults to `yes`). Allowed values:


@@ -178,6 +192,14 @@ The following **preference fields** are supported in request stanzas:
   field comes from the `APT::Solver::Strict-Pinning` configuration
   option.
 
   field comes from the `APT::Solver::Strict-Pinning` configuration
   option.
 

+- **Forbid-New-Install:* (optional, defaults to `no`). Allowed values:
+  `yes`, `no`. When set to `yes` the resolver is forbidden to install
+  new packages in its returned solution.
+
+- **Forbid-Remove:* (optional, defaults to `no`). Allowed values: `yes`,
+  `no`.  When set to `yes` the resolver is forbidden to remove currently
+  installed packages in its returned solution.
+

 - **Solver:** (optional, defaults to the empty string) a purely
   informational string specifying to which solver this request was send
   initially.
 - **Solver:** (optional, defaults to the empty string) a purely
   informational string specifying to which solver this request was send
   initially.


@@ -263,11 +285,11 @@ the user.
 
 #### Solution
 
 
 #### Solution
 

-A solution is a list of Deb 822 stanzas. Each of them could be an
-install stanza (telling APT to install a specific package), a remove
-stanza (telling APT to remove one), or an autoremove stanza (telling APT
-about the *future* possibility of removing a package using the
-Autoremove action).
+A solution is a list of Deb 822 stanzas. Each of them could be an install
+stanza (telling APT to install a specific new package or to upgrade or
+downgrade a package to a specific version), a remove stanza (telling APT to
+remove one), or an autoremove stanza (telling APT about the *future*
+possibility of removing a package using the Autoremove action).

 
 An **install stanza** starts with an Install field and supports the
 following fields:
 
 An **install stanza** starts with an Install field and supports the
 following fields:


@@ -289,6 +311,16 @@ this protocol makes no assumption on the fact that a subsequent
 invocation of an Autoremove action will actually remove the very same
 packages indicated by Autoremove stanzas in the former solution.
 
 invocation of an Autoremove action will actually remove the very same
 packages indicated by Autoremove stanzas in the former solution.
 

+A package can't be installed in multiple versions at the same time, so
+for each package there can at most one version be selected either for
+installation or removal. This especially means that a solver is neither
+allowed to represent package upgrades as a remove of the installed
+version and the installation of another (the remove is implicit and must
+be omitted from the solution) nor is it supported to revert previous
+actions in the solution with later actions. APT is allowed to show
+warnings and might even misbehave in earlier versions if a solver is
+violating this assumption.
+

 In terms of expressivity, install and remove stanzas can carry one
 single field each, as APT-IDs are enough to pinpoint packages to be
 installed/removed. Nonetheless, for protocol readability, it is
 In terms of expressivity, install and remove stanzas can carry one
 single field each, as APT-IDs are enough to pinpoint packages to be
 installed/removed. Nonetheless, for protocol readability, it is


@@ -320,8 +352,9 @@ information to APT using **progress stanzas**. A progress stanza starts
 with the Progress field and might contain the following fields:
 
 - **Progress:** (mandatory). The value of this field is a date and time
 with the Progress field and might contain the following fields:
 
 - **Progress:** (mandatory). The value of this field is a date and time

-  timestamp, in RFC 2822 format. The timestamp provides a time
-  annotation for the progress report.
+  timestamp from the UTC timezone, in RFC 2822 format (see 'date -uR' as
+  an example). The timestamp provides a time annotation for the
+  progress report.

 
 - **Percentage:** (optional). An integer from 0 to 100, representing the
   completion of the dependency solving process, as declared by the
 
 - **Percentage:** (optional). An integer from 0 to 100, representing the
   completion of the dependency solving process, as declared by the