tmpdir,local-exec: implement --local_tmp_root

Add new flag called `--local_tmp_root`, which (if
specified) tells Bazel what temp directory should
locally executed actions use.

Fixes https://github.com/bazelbuild/bazel/issues/4621
Related to https://github.com/bazelbuild/bazel/issues/3215

RELNOTES[NEW]: The new "--local_tmp_root=<path>" flag allows specifying the temp directory for locally executed actions.

Change-Id: Ice69a5e63d0bf4d3b5c9ef4dbdd1ed1c5025f85e
PiperOrigin-RevId: 185509555

1 files changed, 17 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/exec/local/LocalExecutionOptions.java b/src/main/java/com/google/devtools/build/lib/exec/local/LocalExecutionOptions.java
index 08aaa53e33..dfcd5d06d8 100644
--- a/src/main/java/com/google/devtools/build/lib/exec/local/LocalExecutionOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/exec/local/LocalExecutionOptions.java
@@ -60,4 +60,21 @@ public class LocalExecutionOptions extends OptionsBase {
             + "locally executed actions which don't use sandboxing"
   )
   public boolean collectLocalExecutionStatistics;
+
+  @Option(
+    name = "local_tmp_root",
+    defaultValue = "",
+    documentationCategory = OptionDocumentationCategory.EXECUTION_STRATEGY,
+    effectTags = {OptionEffectTag.EXECUTION},
+    help =
+        "Sets the TMPDIR environment variable's value for locally executed actions. If this flag's "
+            + "value is not empty, Bazel exports TMPDIR (on Linux/macOS) or TMP and TEMP (on "
+            + "Windows) with this value for locally executed actions. (This doesn't influence "
+            + "action caching, as TMPDIR/TMP/TEMP are not part of the action's cache key.) If this "
+            + "flag's value is empty, then Bazel picks up the user-defined TMPDIR (on Linux/macOS) "
+            + "or TMP/TEMP (on Windows) and exports that for local actions; and if that value is "
+            + "also empty, Bazel exports \"/tmp\" (on Linux/macOS) or a directory in the execroot "
+            + "(on Windows)."
+  )
+  public String localTmpRoot;
 }