Speed up 'maven' compilation error message regexp

Anchor the regexp at line-start to prevent quadratic behaviour when
it doesn't match (bug#39595).  It's unclear whether the type tag, like
[ERROR], is always present; we keep it optional just in case.

* lisp/progmodes/compile.el (compilation-error-regexp-alist-alist):
Rewrite 'maven' regexp, using rx for clarity.
* etc/compilation.txt (maven): More examples.
* test/lisp/progmodes/compile-tests.el
(compile-tests--test-regexps-data): No leading spaces; they seems to
stem from a misunderstanding in bug#11517.

etc/compilation.txt

@@ -341,6 +341,8 @@ makepp: bla bla `/foo/bar.c' and `/foo/bar.h'
 symbol: maven
 
 FooBar.java:[111,53] no interface expected here
+[ERROR] /Users/cinsk/hello.java:[651,96] ';' expected
+[WARNING] /foo/bar/Test.java:[27,43] unchecked conversion
 
 
 * MIPS lint; looks good for SunPro lint also

lisp/progmodes/compile.el

@@ -268,12 +268,24 @@ of[ \t]+\"?\\([a-zA-Z]?:?[^\":\n]+\\)\"?:" 3 2 nil (1))
     (jikes-file
      "^\\(?:Found\\|Issued\\) .* compiling \"\\(.+\\)\":$" 1 nil nil 0)
 
-
-    ;; This used to be pathologically slow on long lines (Bug#3441),
-    ;; due to matching filenames via \\(.*?\\).  This might be faster.
     (maven
      ;; Maven is a popular free software build tool for Java.
-     "\\(\\[WARNING\\] *\\)?\\([^ \n]\\(?:[^\n :]\\| [^-/\n]\\|:[^ \n]\\)*?\\):\\[\\([0-9]+\\),\\([0-9]+\\)\\] " 2 3 4 (1))
+     ,(rx bol
+          ;; It is unclear whether the initial [type] tag is always present.
+          (? "["
+             (or "ERROR" (group-n 1 "WARNING") (group-n 2 "INFO"))
+             "] ")
+          (group-n 3                    ; File
+                   (not (any "\n ["))
+                   (* (or (not (any "\n :"))
+                          (: " " (not (any "\n/-")))
+                          (: ":" (not (any "\n ["))))))
+          ":["
+          (group-n 4 (+ digit))         ; Line
+          ","
+          (group-n 5 (+ digit))         ; Column
+          "] ")
+     3 4 5 (1 . 2))
 
     (jikes-line
      "^ *\\([0-9]+\\)\\.[ \t]+.*\n +\\(<-*>\n\\*\\*\\* \\(?:Error\\|Warnin\\(g\\)\\)\\)"

test/lisp/progmodes/compile-tests.el

@@ -242,7 +242,7 @@
     ;; maven
     ("FooBar.java:[111,53] no interface expected here"
      1 53 111 "FooBar.java" 2)
-    ("  [ERROR] /Users/cinsk/hello.java:[651,96] ';' expected"
+    ("[ERROR] /Users/cinsk/hello.java:[651,96] ';' expected"
      15 96 651 "/Users/cinsk/hello.java" 2) ;Bug#11517.
     ("[WARNING] /foo/bar/Test.java:[27,43] unchecked conversion"
      11 43 27 "/foo/bar/Test.java" 1) ;Bug#20556