Add a repeatable string list flag rule to skylib

docs/common_settings_doc.md

@@ -126,6 +126,24 @@ A string list-typed build setting that can be set on the command line
 | <a id="string_list_flag-scope"></a>scope |  The scope indicates where a flag can propagate to   | String | optional |  `"universal"`  |
 
 
+<a id="string_list_repeatable_flag"></a>
+
+## string_list_repeatable_flag
+
+<pre>
+string_list_repeatable_flag(<a href="#string_list_repeatable_flag-name">name</a>)
+</pre>
+
+A string list-typed build setting that can be accumulated on the command line
+
+**ATTRIBUTES**
+
+
+| Name  | Description | Type | Mandatory | Default |
+| :------------- | :------------- | :------------- | :------------- | :------------- |
+| <a id="string_list_repeatable_flag-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/concepts/labels#target-names">Name</a> | required |  |
+
+
 <a id="string_list_setting"></a>
 
 ## string_list_setting

rules/common_settings.bzl

@@ -123,6 +123,12 @@ string_list_flag = rule(
     doc = "A string list-typed build setting that can be set on the command line",
 )
 
+string_list_repeatable_flag = rule(
+    implementation = _impl,
+    build_setting = config.string_list(flag = True, repeatable = True),
+    doc = "A string list-typed build setting that can be accumulated on the command line",
+)
+
 string_list_setting = rule(
     implementation = _impl,
     build_setting = config.string_list(),

tests/common_settings_test.sh

@@ -66,7 +66,8 @@ def _volcano_impl(ctx):
     height = ctx.attr.height[BuildSettingInfo].value,
     active = ctx.attr.active[BuildSettingInfo].value,
     namer = ctx.attr.namer[BuildSettingInfo].value,
-    nicknames = ctx.attr.nicknames[BuildSettingInfo].value
+    nicknames = ctx.attr.nicknames[BuildSettingInfo].value,
+    hazards = ctx.attr.hazards[BuildSettingInfo].value
   )
   print(description)
 
@@ -77,6 +78,7 @@ volcano = rule(
     "active" : attr.label(),
     "namer": attr.label(),
     "nicknames": attr.label(),
+    "hazards": attr.label(),
   }
 )
 EOF
@@ -89,6 +91,7 @@ load(
   "bool_flag",
   "string_flag",
   "string_list_flag",
+  "string_list_repeatable_flag",
 )
 load("//volcano:rules.bzl", "volcano")
 
@@ -113,6 +116,11 @@ string_list_flag(
   build_setting_default = ["loowit", "loowitiatkla", "lavelatla"]
 )
 
+string_list_repeatable_flag(
+  name = "hazards-flag",
+  build_setting_default = ["lava", "pyroclastic-flow", "ash"]
+)
+
 int_setting(
   name = "height-setting",
   build_setting_default = 9677
@@ -124,6 +132,7 @@ volcano(
   active = ":active-flag",
   namer = ":namer-flag",
   nicknames = ":nicknames-flag",
+  hazards = ":hazards-flag",
 )
 EOF
 
@@ -136,12 +145,15 @@ function test_can_set_flags() {
   bazel build volcano:mt-st-helens --//volcano:height-flag=8366 \
     --//volcano:active-flag=False --//volcano:namer-flag=puyallup-tribe \
     --//volcano:nicknames-flag=volcano-mc-volcanoface \
+    --//volcano:hazards-flag=lava \
+    --//volcano:hazards-flag=hydrogen-sulfide \
     >"$TEST_log" 2>&1 || fail "Expected test to pass"
 
   expect_log "active = False"
   expect_log "height = 8366"
   expect_log "namer = \"puyallup-tribe\""
   expect_log "nicknames = \[\"volcano-mc-volcanoface\"\]"
+  expect_log "hazards = \[\"lava\"\, \"hydrogen-sulfide\"]"
 }
 
 function test_cannot_set_settings() {