Stdin was picking up info noise as the manifest

.github/bump-version.get.sh

@@ -28,6 +28,8 @@ if [ -z "${VERSFILES}" ] ; then
 fi
 
 # Read the versions.
+CARGOERR=$(mktemp)
+trap 'rm -f "${CARGOERR}"' EXIT
 CURRENTVERS=""
 for FILE in ${VERSFILES} ; do
     # Parse each version file according to its type.
@@ -40,12 +42,20 @@ for FILE in ${VERSFILES} ; do
         # read-manifest reports only the package this manifest defines. `cargo metadata` resolves the
         # entire workspace no matter which member it's pointed at and orders packages alphabetically,
         # so it returned whichever member sorted first instead of the file we're reading.
-        if ! MANIFEST_JSON=$(cargo read-manifest --manifest-path "${FILE}" 2>&1) ; then
-            # A virtual manifest defines no package, so it has no version to contribute.
-            if [[ ${MANIFEST_JSON} == *"is a virtual manifest"* ]] ; then
-                continue
-            fi
-            echo "${MANIFEST_JSON}" 1>&2
+        # Stderr goes to a file rather than into the captured stdout: when the repo pins a toolchain
+        # that isn't installed yet, the rustup shim writes "info: ..." progress lines there, and
+        # merging them with 2>&1 handed them to jq as if they were the manifest.
+        CARGOSTATUS=0
+        MANIFEST_JSON=$(cargo read-manifest --manifest-path "${FILE}" 2>"${CARGOERR}") || CARGOSTATUS=$?
+        # A virtual manifest defines no package, so it has no version to contribute. We expect that,
+        # so swallow the complaint cargo makes about it.
+        if [ "${CARGOSTATUS}" -ne 0 ] && grep -q "is a virtual manifest" "${CARGOERR}" ; then
+            continue
+        fi
+        # The file is only a holding pen to keep stderr away from jq. Anything else cargo had to say
+        # still reaches the log, whether or not it succeeded.
+        cat "${CARGOERR}" 1>&2
+        if [ "${CARGOSTATUS}" -ne 0 ] ; then
             exit 1
         fi
         VERS=$(echo "${MANIFEST_JSON}" | jq -re '.version')

.github/spec/get_spec.sh

@@ -6,9 +6,24 @@ Describe 'bump-version.get.sh'
     setup_repo() {
         REPO=$(mktemp -d)
         mkdir -p "${REPO}/.git"
+        ORIGPATH="${PATH}"
     }
     cleanup_repo() {
         rm -rf "${REPO}"
+        PATH="${ORIGPATH}"
+    }
+
+    # Stands in for the rustup shim, which announces itself on stderr while it installs a pinned
+    # toolchain before handing off to the real cargo.
+    stub_noisy_cargo() {
+        mkdir -p "${REPO}/.stub-bin"
+        {
+            printf '#!/bin/sh\n'
+            printf "echo \"info: syncing channel updates for '1.93.1-x86_64-unknown-linux-gnu'\" 1>&2\n"
+            printf 'exec %s "$@"\n' "$(command -v cargo)"
+        } > "${REPO}/.stub-bin/cargo"
+        chmod +x "${REPO}/.stub-bin/cargo"
+        PATH="${REPO}/.stub-bin:${PATH}"
     }
 
     write_crate() {
@@ -70,4 +85,24 @@ Describe 'bump-version.get.sh'
         The output should equal "4.5.6-pre"
         The status should be success
     End
+
+    # Regression: cargo's stderr was folded into its stdout with 2>&1, so any chatter ahead of the
+    # JSON reached jq and it died with "Invalid numeric literal". Keeping the two apart must not cost
+    # us the chatter itself, which is worth having in the log.
+    It 'keeps cargo chatter out of the parsed json but still logs it'
+        write_crate . solo 9.8.7-pre
+        stub_noisy_cargo
+        When call run_get
+        The output should equal "9.8.7-pre"
+        The stderr should include "syncing channel updates"
+        The status should be success
+    End
+
+    It 'still reports cargo errors that are not a virtual manifest'
+        printf 'this is not valid toml\n' > "${REPO}/Cargo.toml"
+        When call run_get
+        The output should equal ""
+        The stderr should not equal ""
+        The status should be failure
+    End
 End