fix for #4534, find xcode without spotlight

This avoids using spotlight to find Xcode if it can, avoiding some times when Spotlight has been unreliable on the CO machines. It also solves #4503 by making the selection of Xcode on CI machines deterministic (given identical installs of Xcode).

scripts/swift-version.sh

@@ -1,37 +1,66 @@
+#!/usr/bin/env bash
+
 get_swift_version() {
-    swift_command=$@
-    $swift_command --version 2>/dev/null | sed -ne 's/^Apple Swift version \([^\b ]*\).*/\1/p'
+    "$1" --version 2>/dev/null | sed -ne 's/^Apple Swift version \([^\b ]*\).*/\1/p'
 }
 
-find_xcode_for_swift() {
-    # First check if the currently active one is fine
-    version="$(get_swift_version xcrun swift || true)"
-    if [[ "$version" = "$1" ]]; then
-        export DEVELOPER_DIR="$(xcode-select -p)"
-        return 0
+test_xcode_for_swift_version() {
+    if [ -z "$1" ] || [ -z "$2" ]; then
+        echo "test_xcode_for_swift_version called with empty parameter(s): `$1` or `$2`" >&2
+        exit 1
     fi
+    local path=$1
+    local required_version=$2
+
+    for swift in "$path"/Toolchains/*.xctoolchain/usr/bin/swift; do
+        if [[ $(get_swift_version "$swift") == "$required_version" ]]; then
+            return 0
+        fi
+    done
+    return 1
+}
 
-    local xcodes dev_dir version
+find_xcode_for_swift() {
+    local path required_version
+
+    if [ -z "$1" ]; then
+        echo "find_xcode_for_swift requres a Swift version" >&2
+        exit 1
+    fi
+    required_version=$1
+
+    # First check if the currently active one is fine, unless we are in a CI run
+    if [ -z "$JENKINS_HOME" ]; then
+        if [[ $(get_swift_version `xcrun -f swift`) = "$required_version" ]]; then
+            export DEVELOPER_DIR=$(xcode-select -p)
+            return 0
+        fi
+    fi
 
-    # Check all installed copies of Xcode for the desired Swift version
-    xcodes=()
-    dev_dir="Contents/Developer"
-    for dir in $(mdfind "kMDItemCFBundleIdentifier == 'com.apple.dt.Xcode'" 2>/dev/null); do
-        [[ -d "$dir" && -n "$(ls -A "$dir/$dev_dir")" ]] && xcodes+=("$dir/$dev_dir")
+    # Check all of the items in /Applications that look promising per #4534
+    for path in /Applications/Xcode*.app/Contents/Developer; do
+        if test_xcode_for_swift_version "$path" "$required_version"; then
+            export DEVELOPER_DIR=$path
+            return 0
+        else
+            echo "nope: $path"
+        fi
     done
-
-    for xcode in "${xcodes[@]}"; do
-        for swift in "$xcode"/Toolchains/*.xctoolchain/usr/bin/swift; do
-            version="$(get_swift_version $swift)"
-            if [[ "$version" = "$1" ]]; then
-                export DEVELOPER_DIR="$xcode"
-                return 0
-            fi
-        done
+
+    # Use Spotlight to see if we can find others installed copies of Xcode
+    for path in $(mdfind "kMDItemCFBundleIdentifier == 'com.apple.dt.Xcode'" 2>/dev/null); do
+        path="$path/Contents/Developer"
+        if [ ! -d "$path" ]; then
+            continue
+        fi
+        if test_xcode_for_swift_version "$path" "$required_version"; then
+            export DEVELOPER_DIR=$path
+            return 0
+        fi
     done
-
-    >&2 echo "No version of Xcode found that supports Swift $1"
-    return 1
+    
+    echo "No version of Xcode found that supports Swift $required_version" >&2
+    exit 1
 }
 
 if [[ "$REALM_SWIFT_VERSION" ]]; then
@@ -42,3 +71,7 @@ else
         export DEVELOPER_DIR="$(xcode-select -p)"
     fi
 fi
+
+return 2>/dev/null || { # only run if called directly
+    echo "Found Swift version $REALM_SWIFT_VERSION in $DEVELOPER_DIR"
+}