==========
shellcheck - FAILED


 ====== Checking before the patch ======
No files specified.

Usage: shellcheck [OPTIONS...] FILES...
  -a                  --check-sourced            Include warnings from sourced files
  -C[WHEN]            --color[=WHEN]             Use color (auto, always, never)
  -i CODE1,CODE2..    --include=CODE1,CODE2..    Consider only given types of warnings
  -e CODE1,CODE2..    --exclude=CODE1,CODE2..    Exclude types of warnings
                      --extended-analysis=bool   Perform dataflow analysis (default true)
  -f FORMAT           --format=FORMAT            Output format (checkstyle, diff, gcc, json, json1, quiet, tty)
                      --list-optional            List checks disabled by default
                      --norc                     Don't look for .shellcheckrc files
                      --rcfile=RCFILE            Prefer the specified configuration file over searching for one
  -o check1,check2..  --enable=check1,check2..   List of optional checks to enable (or 'all')
  -P SOURCEPATHS      --source-path=SOURCEPATHS  Specify path when looking for sourced files ("SCRIPTDIR" for script's dir)
  -s SHELLNAME        --shell=SHELLNAME          Specify dialect (sh, bash, dash, ksh, busybox)
  -S SEVERITY         --severity=SEVERITY        Minimum severity of errors to consider (error, warning, info, style)
  -V                  --version                  Print version information
  -W NUM              --wiki-link-count=NUM      The number of wiki links to show, when applicable
  -x                  --external-sources         Allow 'source' outside of FILES
                      --help                     Show this usage summary and exit

 ====== Checking the tree with the patch ======
tools/testing/selftests/tc-testing/tdc.sh was shellcheck compliant, not anymore
New errors added
--- /tmp/tmp.kqZdplbMkP	2025-06-14 10:32:52.088226541 -0700
+++ /tmp/tmp.1SHoQCwgXn	2025-06-14 10:32:52.849222239 -0700
@@ -0,0 +1,18 @@
+
+In tdc.sh line 8:
+   if [ $? -ne 0 ]; then
+        ^-- SC2181 (style): Check exit code directly with e.g. 'if ! mycmd;', not indirectly with $?.
+
+
+In tdc.sh line 71:
+./tdc.py -J`nproc`
+           ^-----^ SC2046 (warning): Quote this to prevent word splitting.
+           ^-----^ SC2006 (style): Use $(...) notation instead of legacy backticks `...`.
+
+Did you mean: 
+./tdc.py -J$(nproc)
+
+For more information:
+  https://www.shellcheck.net/wiki/SC2046 -- Quote this to prevent word splitt...
+  https://www.shellcheck.net/wiki/SC2006 -- Use $(...) notation instead of le...
+  https://www.shellcheck.net/wiki/SC2181 -- Check exit code directly with e.g...