make rule incremental to avoid expensive calculation

Karim Alweheshy · Karim Alweheshy · commit 854e37eae6cc · 2025-03-23T21:19:06.000+01:00
diff --git a/xcodeproj/internal/custom_toolchain.bzl b/xcodeproj/internal/custom_toolchain.bzl
@@ -10,10 +10,10 @@ def _get_xcode_product_version(*, xcode_config):
 """)
 
     version_components = raw_version.split(".")
-    if len(version_components) < 4:
-        # This will result in analysis cache misses, but it's better than
-        # failing
-        return raw_version
+    if len(version_components) != 4:
+        fail("""\
+`xcode_config.xcode_version` returned an unexpected number of components: {}
+""".format(len(version_components)))
 
     return version_components[3]
 
@@ -25,7 +25,10 @@ def _custom_toolchain_impl(ctx):
     toolchain_name_base = ctx.attr.toolchain_name
     toolchain_id = "com.rules_xcodeproj.{}.{}".format(toolchain_name_base, xcode_version)
     full_toolchain_name = "{}{}".format(toolchain_name_base, xcode_version)
-    toolchain_dir = ctx.actions.declare_directory(full_toolchain_name + ".xctoolchain")
+
+    # Create two directories - one for symlinks, one for the final overridden toolchain
+    symlink_toolchain_dir = ctx.actions.declare_directory(full_toolchain_name + ".symlink.xctoolchain")
+    final_toolchain_dir = ctx.actions.declare_directory(full_toolchain_name + ".xctoolchain")
 
     resolved_overrides = {}
     override_files = []
@@ -53,29 +56,36 @@ def _custom_toolchain_impl(ctx):
             if tool_name:  # Skip empty names
                 resolved_overrides[tool_name] = stub_file.path
 
+    # Instead of passing the full map of overrides, just pass the tool names
+    # This way, changes to the stubs don't trigger a rebuild
+    tool_names_list = " ".join(resolved_overrides.keys())
+
     overrides_list = " ".join(["{}={}".format(k, v) for k, v in resolved_overrides.items()])
 
-    script_file = ctx.actions.declare_file(full_toolchain_name + "_setup.sh")
+    symlink_script_file = ctx.actions.declare_file(full_toolchain_name + "_symlink.sh")
+    override_script_file = ctx.actions.declare_file(full_toolchain_name + "_override.sh")
+    override_marker = ctx.actions.declare_file(full_toolchain_name + ".override.marker")
 
+    # Create symlink script
     ctx.actions.expand_template(
         template = ctx.file._symlink_template,
-        output = script_file,
+        output = symlink_script_file,
         is_executable = True,
         substitutions = {
-            "%overrides_list%": overrides_list,
-            "%toolchain_dir%": toolchain_dir.path,
+            "%tool_names_list%": tool_names_list,
+            "%toolchain_dir%": symlink_toolchain_dir.path,
             "%toolchain_id%": toolchain_id,
             "%toolchain_name_base%": full_toolchain_name,
             "%xcode_version%": xcode_version,
         },
     )
 
+    # First run the symlinking script to set up the toolchain
     ctx.actions.run_shell(
-        outputs = [toolchain_dir],
-        inputs = override_files,
-        tools = [script_file],
-        mnemonic = "CreateCustomToolchain",
-        command = script_file.path,
+        outputs = [symlink_toolchain_dir],
+        tools = [symlink_script_file],
+        mnemonic = "CreateSymlinkToolchain",
+        command = symlink_script_file.path,
         execution_requirements = {
             "local": "1",
             "no-cache": "1",
@@ -85,7 +95,36 @@ def _custom_toolchain_impl(ctx):
         use_default_shell_env = True,
     )
 
-    runfiles = ctx.runfiles(files = override_files + [script_file])
+    if override_files:
+        ctx.actions.expand_template(
+            template = ctx.file._override_template,
+            output = override_script_file,
+            is_executable = True,
+            substitutions = {
+                "%final_toolchain_dir%": final_toolchain_dir.path,
+                "%marker_file%": override_marker.path,
+                "%overrides_list%": overrides_list,
+                "%symlink_toolchain_dir%": symlink_toolchain_dir.path,
+                "%tool_names_list%": tool_names_list,
+            },
+        )
+
+        ctx.actions.run_shell(
+            inputs = override_files + [symlink_toolchain_dir],
+            outputs = [final_toolchain_dir, override_marker],
+            tools = [override_script_file],
+            mnemonic = "ApplyCustomToolchainOverrides",
+            command = override_script_file.path,
+            execution_requirements = {
+                "local": "1",
+                "no-cache": "1",
+                "no-sandbox": "1",
+                "requires-darwin": "1",
+            },
+            use_default_shell_env = True,
+        )
+
+    runfiles = ctx.runfiles(files = override_files + [symlink_script_file, override_script_file, override_marker])
 
     toolchain_provider = ToolchainInfo(
         name = full_toolchain_name,
@@ -94,7 +133,7 @@ def _custom_toolchain_impl(ctx):
 
     return [
         DefaultInfo(
-            files = depset([toolchain_dir]),
+            files = depset([final_toolchain_dir if override_files else symlink_toolchain_dir]),
             runfiles = runfiles,
         ),
         toolchain_provider,
@@ -109,6 +148,10 @@ custom_toolchain = rule(
             doc = "Map from stub target to comma-separated list of tool names that should use that stub",
         ),
         "toolchain_name": attr.string(mandatory = True),
+        "_override_template": attr.label(
+            allow_single_file = True,
+            default = Label("//xcodeproj/internal/templates:custom_toolchain_override.sh"),
+        ),
         "_symlink_template": attr.label(
             allow_single_file = True,
             default = Label("//xcodeproj/internal/templates:custom_toolchain_symlink.sh"),
diff --git a/xcodeproj/internal/templates/custom_toolchain_override.sh b/xcodeproj/internal/templates/custom_toolchain_override.sh
@@ -0,0 +1,64 @@
+#!/bin/bash
+set -euo pipefail
+
+SYMLINK_TOOLCHAIN_DIR="%symlink_toolchain_dir%"
+FINAL_TOOLCHAIN_DIR="%final_toolchain_dir%"
+MARKER_FILE="%marker_file%"
+
+# Get the default toolchain path
+DEFAULT_TOOLCHAIN=$(xcrun --find clang | sed 's|/usr/bin/clang$||')
+
+OVERRIDES_FILE=$(mktemp)
+echo "%overrides_list%" > "$OVERRIDES_FILE"
+
+TOOL_NAMES_FILE=$(mktemp)
+echo "%tool_names_list%" > "$TOOL_NAMES_FILE"
+
+for tool_name in $(cat "$TOOL_NAMES_FILE"); do
+    VALUE=""
+    for override in $(cat "$OVERRIDES_FILE"); do
+        KEY="${override%%=*}"
+        if [[ "$KEY" == "$tool_name" ]]; then
+            VALUE="${override#*=}"
+            break
+        fi
+    done
+
+    if [[ -z "$VALUE" ]]; then
+        echo "Error: No override found for tool: $tool_name"
+        echo "ERROR: No override found for tool: $tool_name" >> "$MARKER_FILE"
+        continue
+    fi
+
+    find "$DEFAULT_TOOLCHAIN" -name "$tool_name" | while read -r default_tool_path; do
+        rel_path="${default_tool_path#"$DEFAULT_TOOLCHAIN/"}"
+        target_file="$FINAL_TOOLCHAIN_DIR/$rel_path"
+
+        mkdir -p "$(dirname "$target_file")"
+
+        override_path="$PWD/$VALUE"
+        cp "$override_path" "$target_file"
+
+        echo "Copied $override_path to $target_file (rel_path: $rel_path)" >> "$MARKER_FILE"
+    done
+done
+
+# Clean up temporary files
+rm -f "$OVERRIDES_FILE"
+rm -f "$TOOL_NAMES_FILE"
+
+# Copy the symlink toolchain to the final toolchain directory
+mkdir -p "$FINAL_TOOLCHAIN_DIR"
+cp -RP "$SYMLINK_TOOLCHAIN_DIR/"* "$FINAL_TOOLCHAIN_DIR/"
+
+# Create a symlink to the toolchain in the user's Library directory
+HOME_TOOLCHAIN_NAME=$(basename "$FINAL_TOOLCHAIN_DIR")
+USER_TOOLCHAIN_PATH="/Users/$(id -un)/Library/Developer/Toolchains/$HOME_TOOLCHAIN_NAME"
+mkdir -p "$(dirname "$USER_TOOLCHAIN_PATH")"
+if [[ -e "$USER_TOOLCHAIN_PATH" || -L "$USER_TOOLCHAIN_PATH" ]]; then
+    rm -rf "$USER_TOOLCHAIN_PATH"
+fi
+ln -sf "$PWD/$FINAL_TOOLCHAIN_DIR" "$USER_TOOLCHAIN_PATH"
+echo "Created symlink: $USER_TOOLCHAIN_PATH -> $PWD/$FINAL_TOOLCHAIN_DIR" >> "$MARKER_FILE"
+
+
diff --git a/xcodeproj/internal/templates/custom_toolchain_symlink.sh b/xcodeproj/internal/templates/custom_toolchain_symlink.sh
@@ -6,67 +6,50 @@ TOOLCHAIN_NAME_BASE="%toolchain_name_base%"
 TOOLCHAIN_DIR="%toolchain_dir%"
 XCODE_VERSION="%xcode_version%"
 
+# Store the list of tools that will be overridden
+TOOL_NAMES_FILE=$(mktemp)
+echo "%tool_names_list%" > "$TOOL_NAMES_FILE"
+
 # Get Xcode version and default toolchain path
 DEFAULT_TOOLCHAIN=$(xcrun --find clang | sed 's|/usr/bin/clang$||')
 XCODE_RAW_VERSION=$(xcodebuild -version | head -n 1)
 
-# Define toolchain names
+# Define toolchain names for reference only
 HOME_TOOLCHAIN_NAME="BazelRulesXcodeProj${XCODE_VERSION}"
-USER_TOOLCHAIN_PATH="/Users/$(id -un)/Library/Developer/Toolchains/${HOME_TOOLCHAIN_NAME}.xctoolchain"
-BUILT_TOOLCHAIN_PATH="$PWD/$TOOLCHAIN_DIR"
 
 mkdir -p "$TOOLCHAIN_DIR"
 
-# Parse overrides into a file for safer processing
-OVERRIDES_FILE=$(mktemp)
-echo "%overrides_list%" > "$OVERRIDES_FILE"
-
 # Process all files from the default toolchain
 find "$DEFAULT_TOOLCHAIN" -type f -o -type l | while read -r file; do
-    base_name="$(basename "$file")"
     rel_path="${file#"$DEFAULT_TOOLCHAIN/"}"
+    base_name=$(basename "$rel_path")
 
     # Skip ToolchainInfo.plist as we'll create our own
     if [[ "$rel_path" == "ToolchainInfo.plist" ]]; then
         continue
     fi
 
-    # Ensure parent directory exists
-    mkdir -p "$TOOLCHAIN_DIR/$(dirname "$rel_path")"
-
-    # Check if this file has an override
-    override_found=false
-    override_value=""
-
-    for override in $(cat "$OVERRIDES_FILE"); do
-        KEY="${override%%=*}"
-        VALUE="${override#*=}"
-
-        if [[ "$KEY" == "$base_name" ]]; then
-            override_value="$VALUE"
-            override_found=true
+    # Check if this file is in the list of tools to be overridden
+    should_skip=0
+    for tool_name in $(cat "$TOOL_NAMES_FILE"); do
+        if [[ "$base_name" == "$tool_name" ]]; then
+            # Skip creating a symlink for overridden tools
+            echo "Skipping symlink for tool to be overridden: $base_name"
+            should_skip=1
             break
         fi
     done
 
-    # Apply the override or create symlink
-    if [[ "$override_found" == "true" ]]; then
-        # Make path absolute
-        override_path="$PWD/$override_value"
-        cp "$override_path" "$TOOLCHAIN_DIR/$rel_path"
-
-        # Make executable if original is executable
-        if [[ -x "$file" ]]; then
-            chmod +x "$TOOLCHAIN_DIR/$rel_path"
-        fi
-    else
-        # If no override found, symlink the original
-        ln -sf "$file" "$TOOLCHAIN_DIR/$rel_path"
+    if [[ $should_skip -eq 1 ]]; then
+        continue
     fi
-done
 
-# Clean up
-rm -f "$OVERRIDES_FILE"
+    # Ensure parent directory exists
+    mkdir -p "$TOOLCHAIN_DIR/$(dirname "$rel_path")"
+
+    # Create symlink to the original file
+    ln -sf "$file" "$TOOLCHAIN_DIR/$rel_path"
+done
 
 # Generate the ToolchainInfo.plist directly with Xcode version information
 cat > "$TOOLCHAIN_DIR/ToolchainInfo.plist" << EOF
@@ -96,8 +79,5 @@ cat > "$TOOLCHAIN_DIR/ToolchainInfo.plist" << EOF
 </plist>
 EOF
 
-mkdir -p "$(dirname "$USER_TOOLCHAIN_PATH")"
-if [[ -e "$USER_TOOLCHAIN_PATH" || -L "$USER_TOOLCHAIN_PATH" ]]; then
-    rm -rf "$USER_TOOLCHAIN_PATH"
-fi
-ln -sf "$BUILT_TOOLCHAIN_PATH" "$USER_TOOLCHAIN_PATH"
+# Clean up
+rm -f "$TOOL_NAMES_FILE"
