To avoid paying the cost of setup and of a full grounding again,
move cycle detection into a separate program and check first if
the solution has cycles.
If it has, ground only the integrity constraint preventing cycles
and solve again.
The "concretizer" section has been extended with a "duplicates:strategy"
attribute, that can take three values:
- "none": only 1 node per package
- "minimal": allow multiple nodes opf specific packages
- "full": allow full duplication for a build tool
This refactor introduces extra indices for triggers and
effect of a condition, so that the corresponding clauses
are evaluated once for every condition they apply to.
All the solution modes we use imply that we have to solve for all
the literals, except for "when possible".
Here we remove a minimization on the number of literals not
solved, and emit directly a fact when a literal *has* to be
solved.
Introduce the concept of "condition sets", i.e. the set of packages on which
a package can require / impose conditions. This currently maps to the link/run
sub-dag of each package + its direct build dependencies.
Parametrize the "condition" and "requirement" logic to multiple nodes.
So far the encoding has a single ID per package, i.e. all the
facts will be node(0, Package). This will prepare the stage for
extending this logic and having multiple nodes from the same
package in a DAG.
Each fact that is deduced from package rules, and start with
a bare package atom, is transformed into a "facts" atom containing
a nested function.
For instance we transformed
version_declared(Package, ...) -> facts(Package, version_declared(...))
This allows us to clearly mark facts that represent a rule on the package,
and will be of help later when we'll have to distinguish the cases where
the atom "Package" is being used referred to package rules and not to a
node in the DAG.
Windows executable paths can have spaces in them, which was leading to
errors when constructing Executable objects: the parser was intended
to handle cases where users could provide an executable along with one
or more space-delimited arguments.
* Executable now assumes that it is constructed with a string argument
that represents the path to the executable, but no additional arguments.
* Invocations of Executable.__init__ that depended on this have been
updated (this includes the core, tests, and one instance of builtin
repository package).
* The error handling for failed invocations of Executable.__call__ now
includes a check for whether the executable name/path contains a
space, to help users debug cases where they (now incorrectly)
concatenate the path and the arguments.
