[build] Add exec_script() inputs as dependencies

Per
https://gn.googlesource.com/gn/+/main/docs/reference.md#buildfile-functions-exec_script_synchronously-run-a-script-and-return-the-output_back-to-top-arguments,
files that a script uses must be passed in `exec_script()`'s
`dependencies` parameter so that the GN generation will re-run if they
change.

Previously, running `fx build` after modifying text in
`//sdk/version_history.json` would rebuild affected files but not
regenerate the build files. GN needs to be reprocessed because GN
variables are generated from the JSON file.

Make similar changes to some other uses of `exec_script()`, and update
and add references to https://fxbug.dev/42141201.

Bug: 325448727
Change-Id: Iffef68d6850dabbfdc86718cbdcd595fc7fef9e8
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1150973
Commit-Queue: David Dorwin <[email protected]>
Reviewed-by: David Turner <[email protected]>

Author: ddorwin

.gn

@@ -43,9 +43,9 @@ exec_script_whitelist = [
   "//build/config/mac/mac_sdk.gni",
   "//build/config/profile/BUILD.gn",
   "//build/config/sanitizers/BUILD.gn",
+  "//build/icu/config.gni",
   "//build/toolchain/default_concurrent_jobs.gni",
   "//build/toolchain/zircon/zircon_toolchain.gni",
-  "//build/icu/config.gni",
   "//zircon/kernel/arch/x86/phys/BUILD.gn",
 ]
 

build/config/fuchsia/platform_version.gni

@@ -9,15 +9,21 @@
 
 _script = "get_platform_version.py"
 version_history_path = "//sdk/version_history.json"
-_process_versions_args = [
-  "-S",  # https://bugs.fuchsia.dev/p/fuchsia/issues/detail?id=62771
+_get_platform_version_args = [
+  "-S",  # See https://fxbug.dev/42141201.
   rebase_path(_script, root_build_dir),
   "--version-history-path",
   rebase_path(version_history_path, root_build_dir),
 ]
+_file_dependencies = [
+  _script,  # See https://fxbug.dev/42141201#comment6.
+  version_history_path,
+]
 
-platform_version =
-    exec_script(python_exe_src, _process_versions_args, "json", [ _script ])
+platform_version = exec_script(python_exe_src,
+                               _get_platform_version_args,
+                               "json",
+                               _file_dependencies)
 
 declare_args() {
   # If true, generate golden files for API level N+1, where N is

build/config/mac/mac_sdk.gni

@@ -14,13 +14,18 @@ declare_args() {
 
 _script = "//build/mac/find_sdk.py"
 _find_sdk_args = [
-  "-S",  # https://bugs.fuchsia.dev/p/fuchsia/issues/detail?id=62771
+  "-S",  # See https://fxbug.dev/42141201.
   rebase_path(_script, root_build_dir),
   "--print-sdk-path",
   mac_sdk_min,
 ]
 _find_sdk_lines =
-    exec_script(python_exe_src, _find_sdk_args, "list lines", [ _script ])
+    exec_script(python_exe_src,
+                _find_sdk_args,
+                "list lines",
+                [
+                  _script,  # See https://fxbug.dev/42141201#comment6.
+                ])
 mac_sdk_version = _find_sdk_lines[1]
 
 if (mac_sdk_path == "") {

build/icu/config.gni

@@ -28,7 +28,11 @@ if (icu_config_use_jiri_hook) {
                     "--fuchsia-dir=" + rebase_path("//", root_build_dir),
                     "--mode=print",
                   ],
-                  "json")
+                  "json",
+                  [
+                    "//third_party/icu/default",
+                    "//third_party/icu/latest",
+                  ])
 }
 
 # A target that verifies that the content of config.json is valid at build time.

build/toolchain/default_concurrent_jobs.gni

@@ -8,7 +8,7 @@ assert(
 
 _script = "get_concurrent_jobs.py"
 _args = [
-  "-S",  # https://bugs.fuchsia.dev/p/fuchsia/issues/detail?id=62771
+  "-S",  # See https://fxbug.dev/42141201.
   rebase_path(_script, root_build_dir),
   "--reserve-memory=1GB",
 ]
@@ -19,4 +19,9 @@ _args += [
 ]
 
 default_concurrent_jobs =
-    exec_script(python_exe_src, _args, "json", [ _script ])
+    exec_script(python_exe_src,
+                _args,
+                "json",
+                [
+                  _script,  # See https://fxbug.dev/42141201#comment6.
+                ])