Replace --combined with --temp-build?

[VPanteleev-S7]

Consider this simple Dub package:

diff --git a/dub.sdl b/dub.sdl
new file mode 100644
index 0000000..ed75c45
--- /dev/null
+++ b/dub.sdl
@@ -0,0 +1,2 @@
+name "test"
+dependency "mir-ion" version="~>2.0"
diff --git a/dub.selections.json b/dub.selections.json
new file mode 100644
index 0000000..73b904a
--- /dev/null
+++ b/dub.selections.json
@@ -0,0 +1,10 @@
+{
+	"fileVersion": 1,
+	"versions": {
+		"mir-algorithm": "3.21.0",
+		"mir-core": "1.6.0",
+		"mir-cpuid": "1.2.11",
+		"mir-ion": "2.2.0",
+		"silly": "1.1.1"
+	}
+}
diff --git a/source/app.d b/source/app.d
new file mode 100644
index 0000000..ab73b3a
--- /dev/null
+++ b/source/app.d
@@ -0,0 +1 @@
+void main() {}

After generating dub.selections.nix, mkDub.nix and test.nix (with --output), and trying to build the result, it fails with:

this derivation will be built:
  /nix/store/lr3xd1azg8a98bpyilyfwix6zqi0qbsg-test.drv
building '/nix/store/lr3xd1azg8a98bpyilyfwix6zqi0qbsg-test.drv'...
unpacking sources
unpacking source archive /nix/store/rk7kivayz7sxa3pmkcrwjicpawmmfbph-source
source root is source
patching sources
updateAutotoolsGnuConfigScriptsPhase
configuring
no configure script, doing nothing
building
             Registered package: mir-core (version: 1.6.0)
             Registered package: mir-cpuid (version: 1.2.11)
             Registered package: silly (version: 1.1.1)
             Registered package: mir-algorithm (version: 3.21.0)
             Registered package: mir-ion (version: 2.2.0)
    Starting Performing "release" build using dmd for x86_64.
    Building test ~master: building configuration [application]
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1474,36): Error: `pure` function `mir.algebraic.Algebraic!(IonExt_).Algebraic.opEquals!().opEquals` cannot call impure function `mir.annotated.U!(Algebraic!(IonExt_)).Annotated.opEquals`
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1474,36): Error: `@nogc` function `mir.algebraic.Algebraic!(IonExt_).Algebraic.opEquals!().opEquals` cannot call non-@nogc function `mir.annotated.U!(Algebraic!(IonExt_)).Annotated.opEquals`
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1474,36): Error: function `mir.annotated.U!(Algebraic!(IonExt_)).Annotated.opEquals` is not `nothrow`
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1429,10): Error: function `mir.algebraic.Algebraic!(IonExt_).Algebraic.opEquals!().opEquals` may throw but is marked as `nothrow`
/nix/store/a9aywjvvc66p4l146hcmik39ddxbghsp-mir-algorithm/source/mir/annotated.d(69,54): Error: template instance `mir.algebraic.Algebraic!(IonExt_).Algebraic.opEquals!()` error instantiating
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/internal/meta.d(683,39):        instantiated from here: `U!(Algebraic!(IonExt_))`
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(858,36):        12 recursive instantiations from here: `ReplaceTypeUnless!(isVariant, This, Algebraic!(IonExt_), IonNull, bool, long, double, string, Blob, Clob, Timestamp, This[], StringMap!(This), Annotated!(This))`
/nix/store/01jyvn04x0r8cd26ysrrca91mvxsj1r2-mir-ion/source/mir/algebraic_alias/ion_ext.d(56,25):        instantiated from here: `Algebraic!(IonExt_)`
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1474,36): Error: `pure` function `mir.algebraic.Algebraic!(Ion_).Algebraic.opEquals!().opEquals` cannot call impure function `mir.annotated.U!(Algebraic!(Ion_)).Annotated.opEquals`
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1474,36): Error: `@nogc` function `mir.algebraic.Algebraic!(Ion_).Algebraic.opEquals!().opEquals` cannot call non-@nogc function `mir.annotated.U!(Algebraic!(Ion_)).Annotated.opEquals`
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1474,36): Error: function `mir.annotated.U!(Algebraic!(Ion_)).Annotated.opEquals` is not `nothrow`
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1429,10): Error: function `mir.algebraic.Algebraic!(Ion_).Algebraic.opEquals!().opEquals` may throw but is marked as `nothrow`
/nix/store/a9aywjvvc66p4l146hcmik39ddxbghsp-mir-algorithm/source/mir/annotated.d(69,54): Error: template instance `mir.algebraic.Algebraic!(Ion_).Algebraic.opEquals!()` error instantiating
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/internal/meta.d(683,39):        instantiated from here: `U!(Algebraic!(Ion_))`
/nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(858,36):        12 recursive instantiations from here: `ReplaceTypeUnless!(isVariant, This, Algebraic!(Ion_), typeof(null), bool, long, double, string, Blob, Clob, Timestamp, This[], StringMap!(This), Annotated!(This))`
/nix/store/a9aywjvvc66p4l146hcmik39ddxbghsp-mir-algorithm/source/mir/algebraic_alias/ion.d(60,22):        instantiated from here: `Algebraic!(Ion_)`
Error dmd failed with exit code 1.
error: builder for '/nix/store/lr3xd1azg8a98bpyilyfwix6zqi0qbsg-test.drv' failed with exit code 2;
       last 10 log lines:
       > /nix/store/01jyvn04x0r8cd26ysrrca91mvxsj1r2-mir-ion/source/mir/algebraic_alias/ion_ext.d(56,25):        instantiated from here: `Algebraic!(IonExt_)`
       > /nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1474,36): Error: `pure` function `mir.algebraic.Algebraic!(Ion_).Algebraic.opEquals!().opEquals` cannot call impure function `mir.annotated.U!(Algebraic!(Ion_)).Annotated.opEquals`
       > /nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1474,36): Error: `@nogc` function `mir.algebraic.Algebraic!(Ion_).Algebraic.opEquals!().opEquals` cannot call non-@nogc function `mir.annotated.U!(Algebraic!(Ion_)).Annotated.opEquals`
       > /nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1474,36): Error: function `mir.annotated.U!(Algebraic!(Ion_)).Annotated.opEquals` is not `nothrow`
       > /nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(1429,10): Error: function `mir.algebraic.Algebraic!(Ion_).Algebraic.opEquals!().opEquals` may throw but is marked as `nothrow`
       > /nix/store/a9aywjvvc66p4l146hcmik39ddxbghsp-mir-algorithm/source/mir/annotated.d(69,54): Error: template instance `mir.algebraic.Algebraic!(Ion_).Algebraic.opEquals!()` error instantiating
       > /nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/internal/meta.d(683,39):        instantiated from here: `U!(Algebraic!(Ion_))`
       > /nix/store/7y1iy4qlxhnykxi56gb4cjwdx5dppj81-mir-core/source/mir/algebraic.d(858,36):        12 recursive instantiations from here: `ReplaceTypeUnless!(isVariant, This, Algebraic!(Ion_), typeof(null), bool, long, double, string, Blob, Clob, Timestamp, This[], StringMap!(This), Annotated!(This))`
       > /nix/store/a9aywjvvc66p4l146hcmik39ddxbghsp-mir-algorithm/source/mir/algebraic_alias/ion.d(60,22):        instantiated from here: `Algebraic!(Ion_)`
       > Error dmd failed with exit code 1.
       For full logs, run 'nix-store -l /nix/store/lr3xd1azg8a98bpyilyfwix6zqi0qbsg-test.drv'.

This seems to be due to a DMD bug. However, this bug only manifests with --combined.

Considering that --combined might be an unusual way to build Dub packages, perhaps it may make sense to replace it with --temp-build?

Replacing --combined with --temp-build causes the above simple package to successfully build.

[lionello]

Latest version 0.4.1 lets you override dubFlags so you can pass --temp-build.

[VPanteleev-S7]

Nice, thank you!