Profile IUSE injection is in EAPI 5.

This reverts commit 9d2b8ee57bf3be941cfdfe13650952d91b9edfdc.

3 files changed, 77 insertions, 7 deletions

diff --git a/eapi-differences.tex b/eapi-differences.tex
index 83e2e58..8ece012 100644
--- a/eapi-differences.tex
+++ b/eapi-differences.tex
@@ -109,6 +109,9 @@ Use dependencies & \compactfeatureref{use-deps} &
 \t{MERGE\_TYPE} & \compactfeatureref{merge-type} &
     No & No & No & No & Yes & Yes \\
 
+Profile \t{IUSE} injection & \compactfeatureref{profile-iuse-injection} &
+    No & No & No & No & No & Yes \\
+
 \t{REPLACING\_VERSIONS} & \compactfeatureref{replace-version-vars} &
     No & No & No & No & Yes & Yes \\
 
@@ -246,6 +249,7 @@ EAPI 5 is EAPI 4 with the following changes:
 
 \begin{compactitem}
 \item Slot operator dependencies, \featureref{slot-operator-deps}.
+\item \t{USE} is calculated differently, \featureref{profile-iuse-injection}.
 \item \t{econf} adds \t{-{}-disable-silent-rules}, \featureref{econf-options}.
 \end{compactitem}
 
diff --git a/ebuild-env-vars.tex b/ebuild-env-vars.tex
index 4d3330e..db636c9 100644
--- a/ebuild-env-vars.tex
+++ b/ebuild-env-vars.tex
@@ -283,9 +283,13 @@ This section discusses the handling of four variables:
 In all cases, the values of \t{IUSE\_REFERENCEABLE} and \t{IUSE\_EFFECTIVE} are undefined during
 metadata generation.
 
-\t{IUSE\_REFERENCEABLE} is equal to the calculated \t{IUSE} value.
+For EAPIs listed in table~\ref{tab:profile-iuse-injection-table} as not supporting profile defined
+\t{IUSE} injection, \t{IUSE\_REFERENCEABLE} is equal to the calculated \t{IUSE} value. For EAPIs
+where profile defined \t{IUSE} injection is supported, \t{IUSE\_REFERENCEABLE} is equal to
+\t{IUSE\_EFFECTIVE}.
 
-\t{IUSE\_EFFECTIVE} contains the following values:
+For EAPIs listed in table~\ref{tab:profile-iuse-injection-table} as not supporting profile defined
+\t{IUSE} injection, \t{IUSE\_EFFECTIVE} contains the following values:
 
 \begin{compactitem}
 \item All values in the calculated \t{IUSE} value.
@@ -294,10 +298,36 @@ metadata generation.
     the profile \t{USE\_EXPAND} variable followed by an underscore.
 \end{compactitem}
 
+\featurelabel{profile-iuse-injection} For EAPIs listed in
+table~\ref{tab:profile-iuse-injection-table} as supporting profile defined \t{IUSE} injection,
+\t{IUSE\_EFFECTIVE} contains the following values:
+
+\begin{compactitem}
+\item All values in the calculated \t{IUSE} value.
+\item All values in the profile \t{IUSE\_IMPLICIT} variable.
+\item All values in the profile variable named \t{USE\_EXPAND\_VALUES\_\$\{v\}}, where \t{\$\{v\}}
+    is any value in the intersection of the profile \t{USE\_EXPAND\_UNPREFIXED} and
+    \t{USE\_EXPAND\_IMPLICIT} variables.
+\item All values for \t{\$\{lower\_v\}\_\$\{x\}}, where \t{\$\{x\}} is all values in the profile
+    variable named \t{USE\_EXPAND\_VALUES\_\$\{v\}}, where \t{\$\{v\}} is any value in the
+    intersection of the profile \t{USE\_EXPAND} and \t{USE\_EXPAND\_IMPLICIT} variables and
+    \t{\$\{lower\_v\}} is the lowercase equivalent of \t{\$\{v\}}.
+\end{compactitem}
+
 The \t{USE} variable is set by the package manager. For each value in \t{IUSE\_EFFECTIVE}, \t{USE}
 shall contain that value if the flag is to be enabled for the ebuild in question, and shall not
-contain that value if it is to be disabled. \t{USE} may contain other flag names that are not
-relevant for the ebuild.
+contain that value if it is to be disabled. In EAPIs listed in
+table~\ref{tab:profile-iuse-injection-table} as not supporting profile defined \t{IUSE} injection,
+\t{USE} may contain other flag names that are not relevant for the ebuild.
+
+For EAPIs listed in table~\ref{tab:profile-iuse-injection-table} as supporting profile defined
+\t{IUSE} injection, the variables named in \t{USE\_EXPAND} and \t{USE\_EXPAND\_UNPREFIXED} shall
+have their profile-provided values reduced to contain only those values that are present in
+\t{IUSE\_EFFECTIVE}.
+
+For EAPIs listed in table~\ref{tab:profile-iuse-injection-table} as supporting profile defined
+\t{IUSE} injection, the package manager must save the calculated value of \t{IUSE\_EFFECTIVE} when
+installing a package. Details are beyond the scope of this specification.
 
 \subsection{\t{REPLACING\_VERSIONS} and \t{REPLACED\_BY\_VERSION}}
 \label{sec:replacing-versions}
diff --git a/profile-variables.tex b/profile-variables.tex
index cb6e63f..cf8cac2 100644
--- a/profile-variables.tex
+++ b/profile-variables.tex
@@ -20,10 +20,36 @@ variables must be treated in this fashion:
 \item \t{CONFIG\_PROTECT\_MASK}
 \end{compactitem}
 
+If the package manager supports any EAPI listed in table~\ref{tab:profile-iuse-injection-table} as
+using profile-defined \t{IUSE} injection, the following variables must also be treated
+incrementally; otherwise, the following variables may or may not be treated incrementally:
+\begin{compactitem}
+\item \t{IUSE\_IMPLICIT}
+\item \t{USE\_EXPAND\_IMPLICIT}
+\item \t{USE\_EXPAND\_UNPREFIXED}
+\end{compactitem}
+
 Other variables, except where they affect only package-manager-specific functionality (such as
 Portage's \t{FEATURES} variable), must not be treated incrementally---later definitions shall
 completely override those in parent profiles.
 
+\ChangeWhenAddingAnEAPI{5}
+\begin{centertable}{Profile-defined \t{IUSE} injection for EAPIs} \label{tab:profile-iuse-injection-table}
+    \begin{tabular}{ l l l }
+        \toprule
+        \multicolumn{1}{c}{\textbf{EAPI}} &
+        \multicolumn{1}{c}{\textbf{Supports profile-defined \t{IUSE} injection?}} \\
+        \midrule
+    \t{0} & No \\
+    \t{1} & No \\
+    \t{2} & No \\
+    \t{3} & No \\
+    \t{4} & No \\
+    \t{5} & Yes \\
+    \bottomrule
+    \end{tabular}
+\end{centertable}
+
 \subsection{Specific variables and their meanings}
 The following variables have specific meanings when set in profiles.
 \begin{description}
@@ -37,11 +63,21 @@ The following variables have specific meanings when set in profiles.
 \item[USE\_EXPAND] Defines a list of variables which are to be treated incrementally and whose
     contents are to be expanded into the USE variable as passed to ebuilds. See
     section~\ref{sec:use-iuse-handling} for details.
-\item[USE\_EXPAND\_HIDDEN] Contains a (possibly empty) subset of names from \t{USE\_EXPAND}. The
-    package manager may use this set as a hint to avoid displaying uninteresting or unhelpful
-    information to an end user.
+\item[USE\_EXPAND\_UNPREFIXED] Similar to \t{USE\_EXPAND}, but no prefix is used. If the repository
+    contains any package using an EAPI supporting profile-defined \t{IUSE} injection (see
+    table~\ref{tab:profile-iuse-injection-table}), this list must contain at least \t{ARCH}. See
+    section~\ref{sec:use-iuse-handling} for details.
+\item[USE\_EXPAND\_HIDDEN] Contains a (possibly empty) subset of names from \t{USE\_EXPAND} and
+    \t{USE\_EXPAND\_UNPREFIXED}. The package manager may use this set as a hint to avoid displaying
+    uninteresting or unhelpful information to an end user.
+\item[USE\_EXPAND\_IMPLICIT, IUSE\_IMPLICIT] Used to inject implicit values into \t{IUSE}. See
+    section~\ref{sec:use-iuse-handling} for details.
 \end{description}
 
+In addition, for EAPIs listed in table~\ref{tab:profile-iuse-injection-table} as supporting profile
+defined \t{IUSE} injection, the variables named in \t{USE\_EXPAND} and \t{USE\_EXPAND\_UNPREFIXED}
+have special handling as described in section~\ref{sec:use-iuse-handling}.
+
 Any other variables set in \t{make.defaults} must be passed on into the ebuild environment as-is,
 and are not required to be interpreted by the package manager.