mkDummySrcTests: avoid unnecessarily adding main.rs (#770)

checks/default.nix

@@ -458,6 +458,10 @@ in
       '';
     };
 
+  multiBinSmoke = myLib.buildPackage {
+    src = myLib.cleanCargoSource ./mkDummySrcTests/multibin/input;
+  };
+
   multiOutputDerivation = myLib.buildPackage {
     src = ./simple;
     outputs = [ "out" "doc" ];

checks/mkDummySrcTests/declaredBinWithMainrs/expected/Cargo.toml

@@ -0,0 +1,8 @@
+[[bin]]
+name = "mybin"
+
+[package]
+build = "cranespecific-dummy.rs"
+edition = "2021"
+name = "mybin"
+version = "0.1.0"

checks/mkDummySrcTests/declaredBinWithMainrs/expected/src/main.rs

@@ -0,0 +1,14 @@
+#![allow(clippy::all)]
+#![allow(dead_code)]
+#![cfg_attr(any(target_os = "none", target_os = "uefi"), no_std)]
+#![cfg_attr(any(target_os = "none", target_os = "uefi"), no_main)]
+
+#[allow(unused_extern_crates)]
+extern crate core;
+
+#[cfg_attr(any(target_os = "none", target_os = "uefi"), panic_handler)]
+fn panic(_info: &::core::panic::PanicInfo<'_>) -> ! {
+    loop {}
+}
+
+pub fn main() {}

checks/mkDummySrcTests/declaredBinWithMainrs/input/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "mybin" # Loadbearing name matching bin
+version = "0.1.0"
+edition = "2021"
+
+[[bin]]
+name = "mybin" # Name of the package

checks/mkDummySrcTests/declaredBinWithMainrs/input/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

checks/mkDummySrcTests/declaredBinWithSrcBin/expected/Cargo.toml

@@ -0,0 +1,8 @@
+[[bin]]
+name = "mybin"
+
+[package]
+build = "cranespecific-dummy.rs"
+edition = "2021"
+name = "mybin"
+version = "0.1.0"

checks/mkDummySrcTests/declaredBinWithSrcBin/expected/src/bin/mybin.rs

@@ -0,0 +1,14 @@
+#![allow(clippy::all)]
+#![allow(dead_code)]
+#![cfg_attr(any(target_os = "none", target_os = "uefi"), no_std)]
+#![cfg_attr(any(target_os = "none", target_os = "uefi"), no_main)]
+
+#[allow(unused_extern_crates)]
+extern crate core;
+
+#[cfg_attr(any(target_os = "none", target_os = "uefi"), panic_handler)]
+fn panic(_info: &::core::panic::PanicInfo<'_>) -> ! {
+    loop {}
+}
+
+pub fn main() {}

checks/mkDummySrcTests/declaredBinWithSrcBin/input/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "mybin" # Loadbearing name matching bin
+version = "0.1.0"
+edition = "2021"
+
+[[bin]]
+name = "mybin" # Name of the package

checks/mkDummySrcTests/declaredBinWithSrcBin/input/src/bin/mybin.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

checks/mkDummySrcTests/default.nix

@@ -110,4 +110,10 @@ linkFarmFromDrvs "cleanCargoToml" (lib.flatten [
 
   customized
   customizedDummyrs
+
+  # https://github.com/ipetkov/crane/issues/768
+  (cmpDummySrc "declaredBinWithMainrs" ./declaredBinWithMainrs)
+  (cmpDummySrc "declaredBinWithSrcBin" ./declaredBinWithSrcBin)
+  (cmpDummySrc "omittedBinWithMainrs" ./omittedBinWithMainrs)
+  (cmpDummySrc "omittedBinWithSrcBin" ./omittedBinWithSrcBin)
 ])

checks/mkDummySrcTests/multibin/input/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

checks/mkDummySrcTests/omittedBinWithMainrs/expected/Cargo.toml

@@ -0,0 +1,5 @@
+[package]
+build = "cranespecific-dummy.rs"
+edition = "2021"
+name = "mybin"
+version = "0.1.0"

checks/mkDummySrcTests/omittedBinWithMainrs/expected/src/main.rs

@@ -0,0 +1,14 @@
+#![allow(clippy::all)]
+#![allow(dead_code)]
+#![cfg_attr(any(target_os = "none", target_os = "uefi"), no_std)]
+#![cfg_attr(any(target_os = "none", target_os = "uefi"), no_main)]
+
+#[allow(unused_extern_crates)]
+extern crate core;
+
+#[cfg_attr(any(target_os = "none", target_os = "uefi"), panic_handler)]
+fn panic(_info: &::core::panic::PanicInfo<'_>) -> ! {
+    loop {}
+}
+
+pub fn main() {}

checks/mkDummySrcTests/omittedBinWithMainrs/input/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "mybin" # Loadbearing name matching bin
+version = "0.1.0"
+edition = "2021"

checks/mkDummySrcTests/omittedBinWithMainrs/input/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

checks/mkDummySrcTests/omittedBinWithSrcBin/expected/Cargo.toml

@@ -0,0 +1,5 @@
+[package]
+build = "cranespecific-dummy.rs"
+edition = "2021"
+name = "mybin"
+version = "0.1.0"

checks/mkDummySrcTests/omittedBinWithSrcBin/expected/src/bin/mybin.rs

@@ -0,0 +1,14 @@
+#![allow(clippy::all)]
+#![allow(dead_code)]
+#![cfg_attr(any(target_os = "none", target_os = "uefi"), no_std)]
+#![cfg_attr(any(target_os = "none", target_os = "uefi"), no_main)]
+
+#[allow(unused_extern_crates)]
+extern crate core;
+
+#[cfg_attr(any(target_os = "none", target_os = "uefi"), panic_handler)]
+fn panic(_info: &::core::panic::PanicInfo<'_>) -> ! {
+    loop {}
+}
+
+pub fn main() {}

checks/mkDummySrcTests/omittedBinWithSrcBin/input/Cargo.toml

@@ -0,0 +1,4 @@
+[package]
+name = "mybin" # Loadbearing name matching bin
+version = "0.1.0"
+edition = "2021"

checks/mkDummySrcTests/omittedBinWithSrcBin/input/src/bin/mybin.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

lib/mkDummySrc.nix

@@ -231,13 +231,18 @@ let
               candidates = candidatePathsForBin t.name;
               inherit (candidates) long;
               short = "${candidates.short}.rs";
+
+              # If we have a declared target that matches the package name then exactly one of the
+              # following needs to be true for a well-formed cargo project:
+              # * the target has an explictly declared path (handled above)
+              # * the project has a `src/main.rs` file (detected above and handled further below)
+              # * the project has a `src/bin/${name}.rs` file which will show up in discoveredBins
+              # Hence if the target's name matches the package name, we have nothing further to add
+              nothingToAdd = t.name == trimmedCargoToml.package.name
+                # Otherwise if the target was already discovered, nothing else for us to add
+                || lib.any (i: i == short || i == long) discoveredBins;
             in
-            if t.name == trimmedCargoToml.package.name
-            then (if hasMainrs then null else srcMainrs)
-            else
-              if lib.any (i: i == short || i == long) discoveredBins
-              then null
-              else short
+            if nothingToAdd then null else short
         ));
 
         allBins = concatStringsSep " " (discoveredBins ++ declaredBins);