fix two typos in apt.conf & apt-cache manpage

[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..c932b8b77955f0f50c2821515bb379781a85122d 100644 (file)
--- a/doc/external-dependency-solver-protocol.txt
+++ b/doc/external-dependency-solver-protocol.txt
@@ -156,17 +156,26 @@ 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.
 
-- **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
-  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.
 
+- **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:
@@ -178,6 +187,14 @@ The following **preference fields** are supported in request stanzas:
   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.
@@ -263,11 +280,11 @@ the user.
 
 #### 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:
@@ -289,6 +306,16 @@ 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.
 
+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