Make | optional for 'gnu' regexp in compilation-mode (bug#80681)HEADmaster

* lisp/progmodes/compile.el
(compilation-error-regexp-alist-alist): Make leading '|'
optional when there are leading spaces (bug#80681).
* etc/compilation.txt (GNU style): New error with two leading
spaces.
* test/lisp/progmodes/compile-tests.el
(compile-test-error-regexps): Increment expected
compilation-num-errors-found.
(compile-tests--test-regexps-data): New error test case for
'gnu' with two leading spaces.  Change expected match for
'cucumber' to match again 'gnu'.

Copyright-paperwork-exempt: yes

1 files changed, 5 insertions, 2 deletions

diff --git a/test/lisp/progmodes/compile-tests.el b/test/lisp/progmodes/compile-tests.el
index 67a713857e3..caf386b4950 100644
--- a/test/lisp/progmodes/compile-tests.el
+++ b/test/lisp/progmodes/compile-tests.el
@@ -121,7 +121,8 @@
     ;; cucumber
     (cucumber "Scenario: undefined step  # features/cucumber.feature:3"
      29 nil 3 "features/cucumber.feature" error)
-    (cucumber "      /home/gusev/.rvm/foo/bar.rb:500:in `_wrap_assertion'"
+    ;; Below is from cucumber but gnu regexp is consistent and matches first.
+    (gnu "      /home/gusev/.rvm/foo/bar.rb:500:in `_wrap_assertion'"
      1 nil 500 "/home/gusev/.rvm/foo/bar.rb" error)
     ;; edg-1 edg-2
     (edg-1 "build/intel/debug/../../../struct.cpp(42): error: identifier \"foo\" is undefined"
@@ -271,6 +272,8 @@
      1 nil 27041 "{standard input}" warning)
     (gnu "boost/container/detail/flat_tree.hpp:589:25:   [ skipping 5 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]"
      1 25 589 "boost/container/detail/flat_tree.hpp" info)
+    ;; Below from pip install, running g++ to compile python extension module.
+    (gnu "  src/add.cpp:8:31: error: invalid operands of types ‘const double’ and ‘const double*’ to binary ‘operator+’" 1 31 8 "src/add.cpp" error)
     ;; Gradle/Kotlin
     (gradle-kotlin
      "e: file:///src/Test.kt:267:5 foo: bar" 4 5 267 "/src/Test.kt" error)
@@ -556,7 +559,7 @@ The test data is in `compile-tests--test-regexps-data'."
                    1 15 5 "alpha.c")))
         (compile--test-error-line test))
 
-      (should (eq compilation-num-errors-found 110))
+      (should (eq compilation-num-errors-found 111))
       (should (eq compilation-num-warnings-found 37))
       (should (eq compilation-num-infos-found 36)))))