cabal-install: stage-qualified package configuration (package build:*) by andreabedini · Pull Request #378 · stable-haskell/cabal

andreabedini · 2026-06-11T05:40:00Z

Adds package <stage>:* project-file stanzas so per-package configuration can target a single build stage.

Commits

Cabal-syntax: allow colons in section header arguments — the field parser rejected : in a section argument, so a header such as package build:pkg was a parse error. Colon-joined argument tokens are now combined into a single SectionArg, letting stage-qualified package stanzas be written unquoted. This accepts strictly more input; all golden parser tests still pass.
cabal-install: stage-qualified package configuration (package build:*) — adds package build:* / package host:* stanzas. The same package can be built in both the build and host stages, so package *, top-level fields and package <name> cannot distinguish them; a stage qualifier can.
- ProjectConfig gains projectConfigStagePackages :: MapMappend Stage PackageConfig (+ lens, parsec parser, field grammar). The legacy parser does not support the new syntax.
- Per-package option lookup and the shared/profiling-lib downward-closed property in ProjectPlanning are made stage-aware, e.g. package build:* shared: False keeps the build stage static even when the host stage is built dynamic.
- Adds a parser test (project-config-stage-packages).
fix: cover QualBase and drop redundant import for -Werror (validate) — latent -Wincomplete-patterns / -Wunused-imports warnings that -Werror promotes to errors only under validate; unrelated to the feature above.

🤖 Generated with Claude Code

Copilot

Pull request overview

Adds support for stage-qualified per-package configuration in cabal.project (e.g. package build:* / package host:*) so options can be applied independently to build-stage vs host-stage packages during staged builds. This is enabled by extending the Cabal fields parser to accept colon-joined section arguments, and then plumbing stage-aware package config through cabal-install’s project parsing and planning.

Changes:

Cabal-syntax: allow : inside section header arguments by joining adjacent arg tokens with colons.
cabal-install: introduce projectConfigStagePackages and apply stage-qualified config during per-package option lookup and shared/profiling closure computation.
Tests + cleanup: add parser test coverage for stage-qualified stanzas and fix a few validate-only -Werror warnings.

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
Cabal-syntax/src/Distribution/Fields/Parser.hs	Permits colon-joined section arguments (enables `package build:*` without quoting).
cabal-install/src/Distribution/Client/ProjectPlanning.hs	Makes per-package option lookup and shared/profiling closure stage-aware.
cabal-install/src/Distribution/Client/ProjectConfig/Types.hs	Adds `projectConfigStagePackages :: MapMappend Stage PackageConfig`.
cabal-install/src/Distribution/Client/ProjectConfig/Parsec.hs	Parses `package <stage>:*` stanzas and stores config per stage.
cabal-install/src/Distribution/Client/ProjectConfig/Lens.hs	Adds lens for `projectConfigStagePackages`.
cabal-install/src/Distribution/Client/ProjectConfig/Legacy.hs	Initializes `projectConfigStagePackages = mempty` (legacy parser unsupported).
cabal-install/src/Distribution/Client/ProjectConfig/FieldGrammar.hs	Extends `ProjectConfig` grammar construction with a default for stage packages.
cabal-install/parser-tests/Tests/ParserTests.hs	Adds parsec-only helper and a test asserting stage-qualified stanza parsing.
cabal-install/parser-tests/Tests/files/project-config-stage-packages/cabal.project	New golden test input for `package build:` / `package host:`.
cabal-install-solver/src/Distribution/Solver/Types/PackagePath.hs	Covers `QualBase` in pretty-printing/qualifier display.
cabal-install-solver/src/Distribution/Solver/Types/PackageConstraint.hs	Ensures constraint scope matching doesn’t accidentally match base-qualified deps.
cabal-install-solver/src/Distribution/Solver/Modular/Validate.hs	Removes unused binding to satisfy `-Werror` under validate.
cabal-install-solver/src/Distribution/Solver/Modular/Linking.hs	Removes unused state read to satisfy `-Werror` under validate.
cabal-install-solver/src/Distribution/Solver/Modular/Builder.hs	Avoids unused pattern binding to satisfy `-Werror` under validate.
cabal-install-solver/src/Distribution/Solver/Modular.hs	Drops unused verbosity imports to satisfy `-Werror` under validate.
Cabal-described/src/Distribution/Described.hs	Drops unused verbosity import to satisfy `-Werror` under validate.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

        Nothing -> do
          lift $ parseWarning pos PWTUnknownSection "target package name or * required"
          return ()


    parseName secName = case runParsecParser parser "<parsePackageName>" (fieldLineStreamFromBS secName) of
      Left _ -> do
        parseFailure pos ("Invalid package name" ++ fromUTF8BS secName)
        return Nothing
      Right cfgTarget -> return $ pure cfgTarget


        -- This is where we merge the options from the project config that
-        -- apply to all packages, all project local packages, and to specific
-        -- named packages
-        global `mappend` local `mappend` perpkg
+        -- apply to all packages, all packages of a given stage, all project
+        -- local packages, and to specific named packages. Later (more specific)
+        -- entries override earlier ones.
+        global `mappend` local `mappend` stagecfg `mappend` perpkg


    <*> blurFieldGrammar L.projectConfigLocalPackages (packageConfigFieldGrammar knownPrograms)
    -- \^ PackageConfig to be applied to locally built packages, specified not inside a stanza
    <*> pure mempty
-  where
    -- \^ PackageConfig applied to explicitly named packages
+    <*> pure mempty
+  where
+    -- \^ PackageConfig applied to all packages of a given stage ('package build:*' etc.)
    provenance = Set.singleton (Explicit source)


These warnings are promoted to errors under validate's -Werror but were masked behind the earlier SolverInstallPlan failure. Clean them up so the build proceeds: - drop unused imports across Dependency, ProjectPlanning(.Types), InLibrary, SetupWrapper, ProjectBuilding.UnpackedPackage, CmdRepl and the InstallPlan and DSL unit-test modules - bind the discarded result of runBuild explicitly (-Wunused-do-bind) - underscore the unused indepGoals parameter in the solver DSL - remove the dead internalSetupMethod, buildTypeAction and selfExecSetupMethod (unexported, unreferenced, not dispatched by runSetupMethod) along with the imports they alone used (Distribution.Make, withEnv/withEnvOverrides/ withExtraPathEnv, System.Environment)

The field parser rejected ':' in a section argument, so a section header such as `package build:pkg` was a parse error. Combine colon-joined argument tokens into a single SectionArg, which lets stage-qualified package stanzas be written unquoted. A colon in this position was previously always an error, so this accepts strictly more input; all Cabal-tests golden parser tests still pass. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

angerman · 2026-06-15T01:19:18Z

+      , -- The legacy parser does not support stage-qualified package stanzas.
+        projectConfigStagePackages = mempty


For the legacy configuration, the current parse would be qualified as host packages I believe.

Yes, it should. I will make sure of it.

angerman · 2026-06-15T01:22:57Z

+package build:*
+    shared: False
+    executable-dynamic: False
+
+package host:*
+    shared: True


Should we test

package * ...

as well? I would assume that applies to build + host?

Isn't that in testProjectConfigStagePackages already?

assertEqual "Unqualified 'package *' should apply to all packages, not a single stage" expectedAll (projectConfigAllPackages (snd (condTreeData config)))

andreabedini · 2026-06-15T07:02:11Z

@angerman I think any unqualified name should be "host: + build:". Then host: will be only host and build: only build. Does it make sense to you?

Add `package <stage>:*` project-file stanzas (e.g. `package build:*`, `package host:*`) so per-package configuration can target a single build stage. The same package can be built in both the build and host stages, so `package *`, top-level fields and `package <name>` cannot distinguish them; a stage qualifier can. - ProjectConfig gains projectConfigStagePackages :: MapMappend Stage PackageConfig (+ lens, parsec parser and field grammar). The legacy parser does not support the new syntax. - Per-package option lookup and the shared/profiling-lib downward-closed property in ProjectPlanning are made stage-aware, so e.g. `package build:* shared: False` keeps the build stage static even when the host stage is built dynamic. - Add a parser test (project-config-stage-packages). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

These are latent warnings that -Wincomplete-patterns / -Wunused-imports promote to errors only under validate's -Werror; they predate and are unrelated to the stage-qualified package configuration work below. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

angerman · 2026-06-15T08:47:20Z

@angerman I think any unqualified name should be "host: + build:". Then host: will be only host and build: only build. Does it make sense to you?

I can kinda see the reasoning. Still wonder if host: would be the more ergonomical ... this is a tricky question.

…e default stage (validate -Werror) - TestCaseUtils.toQPN: add missing QualIndep case (incomplete-patterns -Werror), mirroring QualIndepSetup which already ignores its independence argument. - PackagePath: render the stage prefix only for Build (new dispStage helper); Host stays invisible as the old DefaultNamespace did. Both Pretty instances. - Package.showI / Message.showOption: revert to the original stage-agnostic format; the stage now lives solely on the QPN. - TestCaseUtils: compare the install plan as a set (sort both sides), since the stage-aware UnitId reshuffled the topological order. Fixes the validate build (unit-tests, mem-use-tests) and reduces /Modular/ failures 89 -> 32. Remaining 32 are pre-existing solver-semantics regressions (independent goals, base shims, reinstall protection, setup-dep merging, build-tool exe staging), not rendering. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

hasufell · 2026-06-24T06:52:43Z

Cabal-syntax: allow colons in section header arguments — the field parser rejected : in a section argument, so a header such as package build:pkg was a parse error. Colon-joined argument tokens are now combined into a single SectionArg, letting stage-qualified package stanzas be written unquoted. This accepts strictly more input; all golden parser tests still pass.

What does this mean? I have no idea. package "build:pkg" was accepted before, but now we also accept package build:pkg?

What does "accepts strictly more input" mean?

I'm afraid I can't follow this generated summary.

cabal-install: stage-qualified package configuration (package build:) — adds package build: / package host:* stanzas. The same package can be built in both the build and host stages, so package *, top-level fields and package cannot distinguish them; a stage qualifier can.

Can we start with a clear motivation, even if it is obvious? What are we trying to solve?

What can the end user do now that they couldn't do before?

hasufell · 2026-06-24T06:56:19Z


 colon, openBrace, closeBrace :: Parser ()
+
+-- | A single section argument.


What is a section argument?

Section arguments are what follows the opening a section, e.g.

-- name 'test', argument 'my-test' test my-test ... -- name 'if', arguments 'impl(ghc)' if impl(ghc) ...

hasufell · 2026-06-24T06:56:47Z

+-- was previously a parse error, so this accepts strictly more input.
 sectionArg :: Parser (SectionArg Position)
-sectionArg = tokSym' <|> tokStr <|> tokOther <?> "section parameter"
+sectionArg = do


Where is the test for the new syntax?

The change in Cabal-syntax is not specific to the host: or build: syntax but it is necessary to allow it. I guess I should add some tests to Cabal-syntax to describe this change anyway.

Note: Cabal-syntax has no in-package tests. Tests for the build:*/host:* syntax are in test-parser which is in [cabal-install].

hasufell · 2026-06-24T07:15:22Z

            Right name -> return $ Just name

-data PackageConfigTarget = AllPackages | SpecificPackage !PackageName
+data PackageConfigTarget = AllPackages | AllStagePackages !Stage | SpecificPackage !PackageName


How does this work? We don't have a stage for SpecificPackage?

Actually not, this PR only implements "build:" and "host:", not "build:pkg" or "host:pkg". It's the minimum required for building our ghc.

hasufell · 2026-06-24T07:23:38Z

 showI :: I -> String
-showI (I s v (InRepo pn)) = intercalate ":" [showStage s, "source", prettyShow (PackageIdentifier pn v)]
-showI (I s _v (Inst uid)) = intercalate ":" [showStage s, "installed", prettyShow uid]
+showI (I _s v (InRepo _pn)) = showVer v


Are there some unit tests for this that showcase what the changes are?

See ParserTests.hs and project-config-stage-packages/cabal.project

hasufell · 2026-06-24T07:27:13Z

+-- ordinary (non-cross) builds, where every package is on the 'Host' stage,
+-- stay free of stage noise; only the 'Build' stage is called out explicitly.
+dispStage :: Stage -> Disp.Doc
+dispStage Host = Disp.empty


This seems confusing if the default is build+host?

hasufell · 2026-06-24T07:32:13Z

+-- A base-qualified dependency is never matched by a toplevel/setup/exe scope.
+constraintQualifierMatches (ScopeTarget _) (QualBase _) _ = False
+constraintQualifierMatches (ScopeAnySetupQualifier _) (QualBase _) _ = False
+constraintQualifierMatches (ScopeAnyExeQualifier _) (QualBase _) _ = False


Is this part related to the PR? It seems like an unrelated bugfix?

You are correct. It is unrelated.

andreabedini · 2026-06-24T08:22:02Z

This change is unfortunate but required to be able to parse host:pkg-name correctly, as it stands the parser will stop at :. The commit message describes this well:

Cabal-syntax: allow colons in section header arguments
The field parser rejected ':' in a section argument, so a section header such as
package build:pkg was a parse error. Combine colon-joined argument tokens into
a single SectionArg, which lets stage-qualified package stanzas be written
unquoted. A colon in this position was previously always an error, so this
accepts strictly more input; all Cabal-tests golden parser tests still pass.

480c9c2

andreabedini · 2026-06-24T08:28:14Z

The changes

fix: cover QualBase and drop redundant import for -Werror (validate)
cabal-install: stage-qualified package configuration (package build:*)
are unrelated to the change but needed to get things to work after the rebase on upstream master.

andreabedini · 2026-06-24T09:35:42Z

What does this mean? I have no idea. package "build:pkg" was accepted before, but now we also accept package build:pkg?

Neither package "build:pkg" or package build:pkg were accepted before by the cabal.project parser and the issue is that Cabal-syntax's parseFields (which is a lower level parser shared with cabal files) could not accept that syntax either.

This is using cabal from stable-haskell/master:

/tmp/tmp.bXfC7W68cv 12s
λ cat cabal.project

extra-packages: lens

package build:lens
    ghc-options: -v

/tmp/tmp.bXfC7W68cv
λ cabal build --dry-run lens
Error: [Cabal-7090]
Error parsing project file cabal.project:4:
 - Parse of field '
   unexpected ":"
   expecting section parameter, "{", field or section name or end of file' failed.

/tmp/tmp.bXfC7W68cv
λ hx cabal.project

/tmp/tmp.bXfC7W68cv
λ cat cabal.project

extra-packages: lens

package "build:lens"
    ghc-options: -v

/tmp/tmp.bXfC7W68cv
λ cabal build --dry-run lens
Error: [Cabal-7090]
Error parsing project file cabal.project:4:
 - a 'package' section requires a package name as an argument

Copilot AI review requested due to automatic review settings June 11, 2026 05:40

Copilot started reviewing on behalf of andreabedini June 11, 2026 05:40 View session

Copilot AI reviewed Jun 11, 2026

View reviewed changes

andreabedini and others added 2 commits June 11, 2026 16:19

angerman reviewed Jun 15, 2026

View reviewed changes

andreabedini force-pushed the wip/andrea/stage-qualified-options branch from 033b9c3 to dc184ee Compare June 15, 2026 03:37

andreabedini force-pushed the stable-haskell/master branch from 843fceb to 01d053a Compare June 15, 2026 03:37

andreabedini and others added 2 commits June 15, 2026 15:07

andreabedini force-pushed the wip/andrea/stage-qualified-options branch from dc184ee to e1b10cc Compare June 15, 2026 09:29

hasufell reviewed Jun 24, 2026

View reviewed changes

andreabedini commented Jun 24, 2026

View reviewed changes

		, -- The legacy parser does not support stage-qualified package stanzas.
		projectConfigStagePackages = mempty


		colon, openBrace, closeBrace :: Parser ()

		-- \| A single section argument.

Uh oh!

Conversation

andreabedini commented Jun 11, 2026

Commits

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

andreabedini commented Jun 15, 2026

Uh oh!

angerman commented Jun 15, 2026

Uh oh!

hasufell commented Jun 24, 2026

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

andreabedini Jun 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

hasufell Jun 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

andreabedini Jun 24, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

andreabedini commented Jun 24, 2026

Uh oh!

andreabedini commented Jun 24, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

andreabedini Jun 24, 2026 •

edited

Loading

hasufell Jun 24, 2026 •

edited

Loading

andreabedini Jun 24, 2026 •

edited

Loading