edsp: support generic and solver-specific configs

[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 477bc23eddf94bf3b402c54e7d3d9eb0c681340a..e2bd95866f303abea02de859fbdff9202a7d5672 100644 (file)
--- a/doc/external-dependency-solver-protocol.txt
+++ b/doc/external-dependency-solver-protocol.txt
@@ -5,6 +5,14 @@ external dependency solvers. The protocol is called APT EDSP, for "APT
 External Dependency Solver Protocol".
 
 
 External Dependency Solver Protocol".
 
 

+## Terminology
+
+In the following we use the term **architecture qualified package name**
+(or *arch-qualified package names* for short) to refer to package
+identifiers of the form "package:arch" where "package" is a package name
+and "arch" a dpkg architecture.
+
+

 ## Components
 
 - **APT**: we know this one.
 ## Components
 
 - **APT**: we know this one.


@@ -50,17 +58,25 @@ configuration documentation for more, and more up to date, information.
 - **APT::Solver**: the name of the solver to be used for
   dependency solving. Defaults to `internal`
 
 - **APT::Solver**: the name of the solver to be used for
   dependency solving. Defaults to `internal`
 

+- **Dir::Bin::Solvers**: absolute path of the directory where to look for
+  external solvers. Defaults to `/usr/lib/apt/solvers`.
+

 - **APT::Solver::Strict-Pinning**: whether pinning must be strictly
   respected (as the internal solver does) or can be slightly deviated
   from. Defaults to `yes`.
 
 - **APT::Solver::Strict-Pinning**: whether pinning must be strictly
   respected (as the internal solver does) or can be slightly deviated
   from. Defaults to `yes`.
 

-- **APT::Solver::NAME::Preferences** (where NAME is a solver name):
-  solver-specific user preference string used during dependency solving,
-  when the solver NAME is in use. Check solver-specific documentation
-  for what is supported here. Defaults to the empty string.
+- **APT::Solver::Preferences**: user preference string used during
+  dependency solving by the requested solver. Check the documentation
+  of the solver you are using if and what is supported as a value here.
+  Defaults to the empty string.
+
+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
+of the external solver this option should apply to. These options if set
+override the generic options; for simplicity the documentation will
+refer only to the generic options.

 
 

-- **Dir::Bin::Solvers**: absolute path of the directory where to look for
-  external solvers. Defaults to `/usr/lib/apt/solvers`.

 
 ## Protocol
 
 
 ## Protocol
 


@@ -132,9 +148,9 @@ The following **configuration fields** are supported in request stanzas:
 The following **action fields** are supported in request stanzas:
 
 - **Install:** (optional, defaults to the empty string) A space
 The following **action fields** are supported in request stanzas:
 
 - **Install:** (optional, defaults to the empty string) A space

-  separated list of package names, with *no version attached*, to
-  install. This field denotes a list of packages that the user wants to
-  install, usually via an APT `install` request.
+  separated list of arch-qualified package names, with *no version
+  attached*, to install. This field denotes a list of packages that the
+  user wants to install, usually via an APT `install` request.

 
 - **Remove:** (optional, defaults to the empty string) Same syntax of
   Install. This field denotes a list of packages that the user wants to
 
 - **Remove:** (optional, defaults to the empty string) Same syntax of
   Install. This field denotes a list of packages that the user wants to


@@ -162,8 +178,13 @@ 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.
 

-- **Preferences:** a solver-specific optimization string, usually coming
-  from the `APT::Solver::Preferences` configuration option.
+- **Solver:** (optional, defaults to the empty string) a purely
+  informational string specifying to which solver this request was send
+  initially.
+
+- **Preferences:** (optional, defaults to the empty string)
+  a solver-specific optimization string, usually coming from the
+  `APT::Solver::Preferences` configuration option.

 
 
 #### Package universe
 
 
 #### Package universe


@@ -201,7 +222,7 @@ field. The following fields are supported in package stanzas:
 - **APT-Candidate:** (optional, defaults to `no`). Allowed values:
   `yes`, `no`. When set to `yes`, the corresponding package is the APT
   candidate for installation among all available packages with the same
 - **APT-Candidate:** (optional, defaults to `no`). Allowed values:
   `yes`, `no`. When set to `yes`, the corresponding package is the APT
   candidate for installation among all available packages with the same

-  name.
+  name and architecture.

 
 - **APT-Automatic:** (optional, defaults to `no`). Allowed values:
   `yes`, `no`. When set to `yes`, the corresponding package is marked by
 
 - **APT-Automatic:** (optional, defaults to `no`). Allowed values:
   `yes`, `no`. When set to `yes`, the corresponding package is marked by


@@ -209,6 +230,22 @@ field. The following fields are supported in package stanzas:
   should be removed by the solver only when the Autoremove action is
   requested (see Request section).
 
   should be removed by the solver only when the Autoremove action is
   requested (see Request section).
 

+- **APT-Release:** (optional) The releases the package belongs to, according to
+  APT. The format of this field is multiline with one value per line and the
+  first line (the one containing the field name) empty. Each subsequent line
+  corresponds to one of the releases the package belongs to and looks like
+  this: `o=Debian,a=unstable,n=sid,l=Debian,c=main`. That is, each release line
+  is a comma-separated list of "key=value" pairs, each of which denotes a
+  Release file entry (Origin, Label, Codename, etc.) in the format of
+  APT_PREFERENCES(5).
+
+- **Source:** (optional) The name of the source package the binary
+  package this record is for was built from.
+  This field does NOT include the version of the source package unlike
+  the Source field in the dpkg database. The version is optionally
+  available in the **Source-Version:** field.
+
+

 ### Answer
 
 An answer from the external solver to APT is either a *solution* or an
 ### Answer
 
 An answer from the external solver to APT is either a *solution* or an


@@ -217,11 +254,11 @@ An answer from the external solver to APT is either a *solution* or an
 The following invariant on **exit codes** must hold true. When the
 external solver is *able to find a solution*, it will write the solution
 to standard output and then exit with an exit code of 0. When the
 The following invariant on **exit codes** must hold true. When the
 external solver is *able to find a solution*, it will write the solution
 to standard output and then exit with an exit code of 0. When the

-external solver is *unable to find a solution* (and s aware of that), it
-will write an error to standard output and then exit with an exit code
-of 0. An exit code other than 0 will be interpreted as a solver crash
-with no meaningful error about dependency resolution to convey to the
-user.
+external solver is *unable to find a solution* (and is aware of that),
+it will write an error to standard output and then exit with an exit
+code of 0. An exit code other than 0 will be interpreted as a solver
+crash with no meaningful error about dependency resolution to convey to
+the user.

 
 
 #### Solution
 
 
 #### Solution