Auto merge of #66605 - GuillaumeGomez:drop-python2, r=Mark-Simulacrum

Stop explicitly depending on python 2

This PR revises our previous policy of officially only supporting and testing with python 2 in the CI environment to instead test with python 3. It also changes the defaults to python 3 in our various scripts (usually, by way of `python` rather than `python3` to preserve compatibility with systems that do not have a python 3 available).

The effect of this is that we expect all new patches to support python 3 (and will test as such). We explicitly also expect that patches support python 2.7 as well -- and test as such, though only on one builder. This is intended as a temporary, though likely long-lived, measure to preserve compatibility while looking towards the future which is likely to be a python 3 only world. We do not at this point set a timeline for when we'll drop support for python 2.7; it's plausible that this is months or years into the future, depending on how quickly the ecosystem drops support and how painful it is for us to maintain that support over time.

Closes #65063 (as far as I can tell; please file explicit and separate issues or PRs if not).

Author: bors

README.md

@@ -27,7 +27,7 @@ or reading the [rustc dev guide][rustcguidebuild].
 1. Make sure you have installed the dependencies:
 
    * `g++` 5.1 or later or `clang++` 3.5 or later
-   * `python` 2.7 (but not 3.x)
+   * `python` 3 or 2.7
    * GNU `make` 3.81 or later
    * `cmake` 3.4.3 or later
    * `curl`
@@ -113,7 +113,7 @@ build.
                make \
                diffutils \
                tar \
-               mingw-w64-x86_64-python2 \
+               mingw-w64-x86_64-python \
                mingw-w64-x86_64-cmake \
                mingw-w64-x86_64-gcc
    ```

config.toml.example

@@ -168,11 +168,9 @@
 
 # Python interpreter to use for various tasks throughout the build, notably
 # rustdoc tests, the lldb python interpreter, and some dist bits and pieces.
-# Note that Python 2 is currently required.
 #
-# Defaults to python2.7, then python2. If neither executable can be found, then
-# it defaults to the Python interpreter used to execute x.py.
-#python = "python2.7"
+# Defaults to the Python interpreter used to execute x.py.
+#python = "python"
 
 # Force Cargo to check that Cargo.lock describes the precise dependency
 # set that all the Cargo.toml files create, instead of updating it.

configure

@@ -11,6 +11,7 @@ try() {
     fi
 }
 
+try python3 "$@"
 try python2.7 "$@"
 try python27 "$@"
 try python2 "$@"

src/bootstrap/job.rs

@@ -103,7 +103,12 @@ pub unsafe fn setup(build: &mut Build) {
     };
 
     let parent = OpenProcess(PROCESS_DUP_HANDLE, FALSE, pid.parse().unwrap());
-    assert!(!parent.is_null(), "{}", io::Error::last_os_error());
+    assert!(
+        !parent.is_null(),
+        "PID `{}` doesn't seem to exist: {}",
+        pid,
+        io::Error::last_os_error()
+    );
     let mut parent_handle = ptr::null_mut();
     let r = DuplicateHandle(
         GetCurrentProcess(),

src/bootstrap/sanity.rs

@@ -132,8 +132,6 @@ pub fn check(build: &mut Build) {
         .python
         .take()
         .map(|p| cmd_finder.must_have(p))
-        .or_else(|| cmd_finder.maybe_have("python2.7"))
-        .or_else(|| cmd_finder.maybe_have("python2"))
         .or_else(|| env::var_os("BOOTSTRAP_PYTHON").map(PathBuf::from)) // set by bootstrap.py
         .or_else(|| Some(cmd_finder.must_have("python")));
 

src/ci/docker/arm-android/Dockerfile

@@ -31,7 +31,7 @@ ENV TARGETS=arm-linux-androideabi
 
 ENV RUST_CONFIGURE_ARGS --arm-linux-androideabi-ndk=/android/ndk/arm-14
 
-ENV SCRIPT python2.7 ../x.py test --target $TARGETS
+ENV SCRIPT python3 ../x.py test --target $TARGETS
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh

src/ci/docker/armhf-gnu/Dockerfile

@@ -14,7 +14,7 @@ RUN apt-get update -y && apt-get install -y --no-install-recommends \
       libc6-dev \
       libc6-dev-armhf-cross \
       make \
-      python2.7 \
+      python3 \
       qemu-system-arm \
       xz-utils
 
@@ -78,6 +78,6 @@ COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh
 
 ENV RUST_CONFIGURE_ARGS --qemu-armhf-rootfs=/tmp/rootfs
-ENV SCRIPT python2.7 ../x.py test --target arm-unknown-linux-gnueabihf
+ENV SCRIPT python3 ../x.py test --target arm-unknown-linux-gnueabihf
 
 ENV NO_CHANGE_USER=1

src/ci/docker/disabled/aarch64-gnu/Dockerfile

@@ -14,7 +14,7 @@ RUN apt-get update -y && apt-get install -y --no-install-recommends \
       libc6-dev \
       libc6-dev-arm64-cross \
       make \
-      python2.7 \
+      python3 \
       qemu-system-aarch64 \
       xz-utils
 
@@ -75,5 +75,5 @@ RUN sh /scripts/sccache.sh
 
 ENV RUST_CONFIGURE_ARGS \
       --qemu-aarch64-rootfs=/tmp/rootfs
-ENV SCRIPT python2.7 ../x.py test --target aarch64-unknown-linux-gnu
+ENV SCRIPT python3 ../x.py test --target aarch64-unknown-linux-gnu
 ENV NO_CHANGE_USER=1

src/ci/docker/disabled/asmjs/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   file \
   curl \
   ca-certificates \
-  python \
+  python3 \
   git \
   cmake \
   sudo \
@@ -33,7 +33,7 @@ ENV EMCC_CFLAGS=-O1
 # Emscripten installation is user-specific
 ENV NO_CHANGE_USER=1
 
-ENV SCRIPT python2.7 ../x.py test --target $TARGETS
+ENV SCRIPT python3 ../x.py test --target $TARGETS
 
 # This is almost identical to the wasm32-unknown-emscripten target, so
 # running with assertions again is not useful

src/ci/docker/disabled/dist-aarch64-android/Dockerfile

@@ -19,7 +19,7 @@ ENV RUST_CONFIGURE_ARGS \
       --enable-extended \
       --enable-cargo-openssl-static
 
-ENV SCRIPT python2.7 ../x.py dist --target $HOSTS --host $HOSTS
+ENV SCRIPT python3 ../x.py dist --target $HOSTS --host $HOSTS
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh

src/ci/docker/disabled/dist-armv7-android/Dockerfile

@@ -33,11 +33,11 @@ ENV RUST_CONFIGURE_ARGS \
 # build to finish we use --warn-unresolved-symbols. Note that the missing
 # symbols does not affect std, only the compiler (llvm) and cargo (openssl).
 ENV SCRIPT \
-  python2.7 ../x.py build src/llvm --host $HOSTS --target $HOSTS && \
+  python3 ../x.py build src/llvm --host $HOSTS --target $HOSTS && \
   (export RUSTFLAGS="\"-C link-arg=-Wl,--warn-unresolved-symbols\""; \
     rm /android/ndk/arm && \
     ln -s /android/ndk/arm-14 /android/ndk/arm && \
-    python2.7 ../x.py dist --host $HOSTS --target $HOSTS)
+    python3 ../x.py dist --host $HOSTS --target $HOSTS)
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh

src/ci/docker/disabled/dist-i686-android/Dockerfile

@@ -33,11 +33,11 @@ ENV RUST_CONFIGURE_ARGS \
 # build to finish we use --warn-unresolved-symbols. Note that the missing
 # symbols does not affect std, only the compiler (llvm) and cargo (openssl).
 ENV SCRIPT \
-  python2.7 ../x.py build src/llvm --host $HOSTS --target $HOSTS && \
+  python3 ../x.py build src/llvm --host $HOSTS --target $HOSTS && \
   (export RUSTFLAGS="\"-C link-arg=-Wl,--warn-unresolved-symbols\""; \
     rm /android/ndk/x86 && \
     ln -s /android/ndk/x86-14 /android/ndk/x86 && \
-    python2.7 ../x.py dist --host $HOSTS --target $HOSTS)
+    python3 ../x.py dist --host $HOSTS --target $HOSTS)
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh

src/ci/docker/disabled/dist-powerpcspe-linux/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   file \
   curl \
   ca-certificates \
-  python2.7 \
+  python3 \
   git \
   cmake \
   sudo \
@@ -23,4 +23,4 @@ RUN sh /scripts/sccache.sh
 ENV HOSTS=powerpc-unknown-linux-gnuspe
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/disabled/dist-sparc64-linux/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   file \
   curl \
   ca-certificates \
-  python2.7 \
+  python3 \
   git \
   cmake \
   sudo \
@@ -23,4 +23,4 @@ RUN sh /scripts/sccache.sh
 ENV HOSTS=sparc64-unknown-linux-gnu
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/disabled/dist-x86_64-android/Dockerfile

@@ -19,7 +19,7 @@ ENV RUST_CONFIGURE_ARGS \
       --enable-extended \
       --enable-cargo-openssl-static
 
-ENV SCRIPT python2.7 ../x.py dist --target $HOSTS --host $HOSTS
+ENV SCRIPT python3 ../x.py dist --target $HOSTS --host $HOSTS
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh

src/ci/docker/disabled/dist-x86_64-dragonfly/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   file \
   curl \
   ca-certificates \
-  python2.7 \
+  python3 \
   git \
   cmake \
   sudo \
@@ -33,4 +33,4 @@ ENV \
 ENV HOSTS=x86_64-unknown-dragonfly
 
 ENV RUST_CONFIGURE_ARGS --enable-extended
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/disabled/dist-x86_64-haiku/Dockerfile

@@ -18,7 +18,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   make \
   nasm \
   pkg-config \
-  python2.7 \
+  python3 \
   sudo \
   texinfo \
   wget \
@@ -46,4 +46,4 @@ ENV RUST_CONFIGURE_ARGS --disable-jemalloc \
   --set=$TARGET.cc=x86_64-unknown-haiku-gcc \
   --set=$TARGET.cxx=x86_64-unknown-haiku-g++ \
   --set=$TARGET.llvm-config=/bin/llvm-config-haiku
-ENV SCRIPT python2.7 ../x.py dist --host=$HOST --target=$HOST
+ENV SCRIPT python3 ../x.py dist --host=$HOST --target=$HOST

src/ci/docker/disabled/dist-x86_64-redox/Dockerfile

@@ -19,4 +19,4 @@ ENV \
     CXX_x86_64_unknown_redox=x86_64-unknown-redox-g++
 
 ENV RUST_CONFIGURE_ARGS --enable-extended
-ENV SCRIPT python2.7 ../x.py dist --target x86_64-unknown-redox
+ENV SCRIPT python3 ../x.py dist --target x86_64-unknown-redox

src/ci/docker/dist-aarch64-linux/Dockerfile

@@ -36,4 +36,4 @@ ENV RUST_CONFIGURE_ARGS \
       --enable-extended \
       --enable-profiler \
       --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-android/Dockerfile

@@ -32,7 +32,7 @@ ENV RUST_CONFIGURE_ARGS \
       --x86_64-linux-android-ndk=/android/ndk/x86_64-21 \
       --disable-docs
 
-ENV SCRIPT python2.7 ../x.py dist --target $TARGETS
+ENV SCRIPT python3 ../x.py dist --target $TARGETS
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh

src/ci/docker/dist-arm-linux/Dockerfile

@@ -28,4 +28,4 @@ ENV CC_arm_unknown_linux_gnueabi=arm-unknown-linux-gnueabi-gcc \
 ENV HOSTS=arm-unknown-linux-gnueabi
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-armhf-linux/Dockerfile

@@ -28,4 +28,4 @@ ENV CC_arm_unknown_linux_gnueabihf=arm-unknown-linux-gnueabihf-gcc \
 ENV HOSTS=arm-unknown-linux-gnueabihf
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-armv7-linux/Dockerfile

@@ -28,4 +28,4 @@ ENV CC_armv7_unknown_linux_gnueabihf=armv7-unknown-linux-gnueabihf-gcc \
 ENV HOSTS=armv7-unknown-linux-gnueabihf
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-i586-gnu-i586-i686-musl/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   file \
   curl \
   ca-certificates \
-  python2.7 \
+  python3 \
   git \
   cmake \
   xz-utils \
@@ -46,5 +46,5 @@ ENV CFLAGS_i586_unknown_linux_musl=-Wa,-mrelax-relocations=no
 ENV TARGETS=i586-unknown-linux-gnu,i686-unknown-linux-musl
 
 ENV SCRIPT \
-      python2.7 ../x.py test --target $TARGETS && \
-      python2.7 ../x.py dist --target $TARGETS,i586-unknown-linux-musl
+      python3 ../x.py test --target $TARGETS && \
+      python3 ../x.py dist --target $TARGETS,i586-unknown-linux-musl

src/ci/docker/dist-i686-freebsd/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   file \
   curl \
   ca-certificates \
-  python2.7 \
+  python3 \
   git \
   cmake \
   sudo \
@@ -30,4 +30,4 @@ ENV \
 ENV HOSTS=i686-unknown-freebsd
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-mips-linux/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   file \
   curl \
   ca-certificates \
-  python2.7 \
+  python3 \
   git \
   cmake \
   sudo \
@@ -23,4 +23,4 @@ RUN sh /scripts/sccache.sh
 ENV HOSTS=mips-unknown-linux-gnu
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-mips64-linux/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   file \
   curl \
   ca-certificates \
-  python2.7 \
+  python3 \
   git \
   cmake \
   sudo \
@@ -22,4 +22,4 @@ RUN sh /scripts/sccache.sh
 ENV HOSTS=mips64-unknown-linux-gnuabi64
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-mips64el-linux/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   file \
   curl \
   ca-certificates \
-  python2.7 \
+  python3 \
   git \
   cmake \
   sudo \
@@ -23,4 +23,4 @@ RUN sh /scripts/sccache.sh
 ENV HOSTS=mips64el-unknown-linux-gnuabi64
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-mipsel-linux/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   file \
   curl \
   ca-certificates \
-  python2.7 \
+  python3 \
   git \
   cmake \
   sudo \
@@ -22,4 +22,4 @@ RUN sh /scripts/sccache.sh
 ENV HOSTS=mipsel-unknown-linux-gnu
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-powerpc-linux/Dockerfile

@@ -35,4 +35,4 @@ ENV \
 ENV HOSTS=powerpc-unknown-linux-gnu
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-powerpc64-linux/Dockerfile

@@ -36,4 +36,4 @@ ENV \
 ENV HOSTS=powerpc64-unknown-linux-gnu
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-powerpc64le-linux/Dockerfile

@@ -33,4 +33,4 @@ ENV \
 ENV HOSTS=powerpc64le-unknown-linux-gnu
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS

src/ci/docker/dist-s390x-linux/Dockerfile

@@ -35,4 +35,4 @@ ENV \
 ENV HOSTS=s390x-unknown-linux-gnu
 
 ENV RUST_CONFIGURE_ARGS --enable-extended --disable-docs
-ENV SCRIPT python2.7 ../x.py dist --host $HOSTS --target $HOSTS
+ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS