Merge pull request #5759 from grondo/issue#5755

shell: unset `HWLOC_COMPONENTS` with `hwloc.xmlfile`

Author: mergify[bot]

doc/man1/common/job-shell-options.rst

@@ -38,7 +38,10 @@
        nonzero exit code.
 
    * - :option:`hwloc.xmlfile`
-     - Write hwloc XML gathered by job to a file and set ``HWLOC_XMLFILE``
+     - Write hwloc XML gathered by job to a file and set ``HWLOC_XMLFILE``.
+       Note that this option will also unset ``HWLOC_COMPONENTS`` if set, since
+       presence of this environment variable may cause hwloc to ignore
+       ``HWLOC_XMLFILE``.
 
    * - :option:`output.limit`
      - Set KVS output limit to SIZE bytes, where SIZE may be a floating point

doc/man1/flux-shell.rst

@@ -449,6 +449,8 @@ plugins include:
 .. option:: hwloc.xmlfile
 
   Write the job shell's copy of hwloc XML to a file and set ``HWLOC_XMLFILE``.
+  Note that this option will also unset ``HWLOC_COMPONENTS`` since presence
+  of this environment variable may cause hwloc to ignore ``HWLOC_XMLFILE``.
 
 .. warning::
   The directory referenced by :envvar:`FLUX_JOB_TMPDIR` is cleaned up when the

src/shell/hwloc.c

@@ -62,6 +62,14 @@ static int create_xmlfile (flux_shell_t *shell)
         shell_log_errno ("failed to set HWLOC_XMLFILE in job environment");
         goto error;
     }
+    /*  Note: HWLOC_XMLFILE will be ignored if HWLOC_COMPONENTS is also set
+     *  in the environment, so unset that variable here.
+     */
+    if (flux_shell_unsetenv (shell, "HWLOC_COMPONENTS") < 0
+        && errno != ENOENT) {
+        shell_log_errno ("failed to unset HWLOC_COMPONENTS");
+        goto error;
+    }
     return 0;
 error:
     if (fd >= 0)

t/t2619-job-shell-hwloc.t

@@ -14,6 +14,10 @@ test_expect_success 'shell: HWLOC_XMLFILE is not set for normal jobs' '
 test_expect_success 'shell: -o hwloc.xmlfile sets HWLOC_XMLFILE' '
 	flux run -o hwloc.xmlfile printenv HWLOC_XMLFILE
 '
+test_expect_success 'shell: -o hwloc.xmlfile unsets HWLOC_COMPONENTS' '
+	test_must_fail flux run --env=HWLOC_COMPONENTS=x86 -o hwloc.xmlfile \
+		printenv HWLOC_COMPONENTS
+'
 command -v hwloc-info >/dev/null && test_set_prereq HWLOC_INFO
 test_expect_success HWLOC_INFO 'shell: -o hwloc.xmlfile HWLOC_XMLFILE is valid' '
 	flux run -o hwloc.xmlfile sh -c "hwloc-info --input \$HWLOC_XMLFILE"