pw_assert: Rename assert_backend.h to check_backend.h

The backend for the PW_CHECK macro was originally defined in
assert_backend.h, but it makes more sense for the PW_CHECK backend to be
defined in check_backend.h.

Change-Id: Iaad62d2f872fa66b3ac3864340331a2f7a19086f
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/96740
Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Ewout van Bekkum <ewout@google.com>
diff --git a/pw_assert/BUILD.bazel b/pw_assert/BUILD.bazel
index 5f1b45a..a2a38cd 100644
--- a/pw_assert/BUILD.bazel
+++ b/pw_assert/BUILD.bazel
@@ -76,7 +76,7 @@
 pw_cc_library(
     name = "print_and_abort_backend",
     hdrs =
-        ["print_and_abort_public_overrides/pw_assert_backend/assert_backend.h"],
+        ["print_and_abort_public_overrides/pw_assert_backend/check_backend.h"],
     includes = ["print_and_abort_public_overrides"],
     deps = [":print_and_abort"],
 )
diff --git a/pw_assert/BUILD.gn b/pw_assert/BUILD.gn
index 30df50a..e0c88e3 100644
--- a/pw_assert/BUILD.gn
+++ b/pw_assert/BUILD.gn
@@ -130,7 +130,7 @@
   public_configs = [ ":print_and_abort_backend_overrides" ]
   public_deps = [ ":print_and_abort" ]
   public =
-      [ "print_and_abort_public_overrides/pw_assert_backend/assert_backend.h" ]
+      [ "print_and_abort_public_overrides/pw_assert_backend/check_backend.h" ]
 }
 
 group("print_and_abort_backend.impl") {
diff --git a/pw_assert/docs.rst b/pw_assert/docs.rst
index 702745d..8294f09 100644
--- a/pw_assert/docs.rst
+++ b/pw_assert/docs.rst
@@ -522,7 +522,7 @@
 
 The backend must provide the header
 
-``pw_assert_backend/backend.h``
+``pw_assert_backend/check_backend.h``
 
 and that header must define the following macros:
 
diff --git a/pw_assert/print_and_abort_public_overrides/pw_assert_backend/assert_backend.h b/pw_assert/print_and_abort_public_overrides/pw_assert_backend/check_backend.h
similarity index 100%
rename from pw_assert/print_and_abort_public_overrides/pw_assert_backend/assert_backend.h
rename to pw_assert/print_and_abort_public_overrides/pw_assert_backend/check_backend.h
diff --git a/pw_assert/public/pw_assert/check.h b/pw_assert/public/pw_assert/check.h
index 31ffca7..7c0a276 100644
--- a/pw_assert/public/pw_assert/check.h
+++ b/pw_assert/public/pw_assert/check.h
@@ -111,4 +111,12 @@
 //   Note that for the assert failures, the handler should assume the assert
 //   has already failed (the facade checks the condition before delegating).
 //
+
+// Temporarily check for the presence of the new header for backwards
+// compatibilty. This will be removed once users migrate.
+#if __has_include("pw_assert_backend/check_backend.h")
+#include "pw_assert_backend/check_backend.h"
+#else
+// If the new header doesn't exist, use the old header.
 #include "pw_assert_backend/assert_backend.h"
+#endif  // __has_include("pw_assert_backend/check_backend.h")
diff --git a/pw_assert_basic/BUILD.bazel b/pw_assert_basic/BUILD.bazel
index 95f5a5b..efc1ede 100644
--- a/pw_assert_basic/BUILD.bazel
+++ b/pw_assert_basic/BUILD.bazel
@@ -25,7 +25,7 @@
     name = "headers",
     hdrs = [
         "public/pw_assert_basic/assert_basic.h",
-        "public_overrides/pw_assert_backend/assert_backend.h",
+        "public_overrides/pw_assert_backend/check_backend.h",
     ],
     includes = [
         "public",
diff --git a/pw_assert_basic/BUILD.gn b/pw_assert_basic/BUILD.gn
index 72c22f1..79e0181 100644
--- a/pw_assert_basic/BUILD.gn
+++ b/pw_assert_basic/BUILD.gn
@@ -46,7 +46,7 @@
   public = [
     "public/pw_assert_basic/assert_basic.h",
     "public/pw_assert_basic/handler.h",
-    "public_overrides/pw_assert_backend/assert_backend.h",
+    "public_overrides/pw_assert_backend/check_backend.h",
   ]
 }
 
diff --git a/pw_assert_basic/public_overrides/pw_assert_backend/assert_backend.h b/pw_assert_basic/public_overrides/pw_assert_backend/check_backend.h
similarity index 100%
rename from pw_assert_basic/public_overrides/pw_assert_backend/assert_backend.h
rename to pw_assert_basic/public_overrides/pw_assert_backend/check_backend.h
diff --git a/pw_assert_log/BUILD.bazel b/pw_assert_log/BUILD.bazel
index c27f4b1..bf7dbc9 100644
--- a/pw_assert_log/BUILD.bazel
+++ b/pw_assert_log/BUILD.bazel
@@ -28,7 +28,7 @@
     ],
     hdrs = [
         "public/pw_assert_log/assert_log.h",
-        "public_overrides/pw_assert_backend/assert_backend.h",
+        "public_overrides/pw_assert_backend/check_backend.h",
     ],
     includes = [
         "public",
diff --git a/pw_assert_log/BUILD.gn b/pw_assert_log/BUILD.gn
index 10f8280..b45d8c6 100644
--- a/pw_assert_log/BUILD.gn
+++ b/pw_assert_log/BUILD.gn
@@ -36,7 +36,7 @@
     ":default_config",
   ]
   public_deps = [ "$dir_pw_log" ]
-  public = [ "public_overrides/pw_assert_backend/assert_backend.h" ]
+  public = [ "public_overrides/pw_assert_backend/check_backend.h" ]
   deps = [
     "$dir_pw_assert:config",
     "$dir_pw_assert:facade",
diff --git a/pw_assert_log/public_overrides/pw_assert_backend/assert_backend.h b/pw_assert_log/public_overrides/pw_assert_backend/check_backend.h
similarity index 100%
rename from pw_assert_log/public_overrides/pw_assert_backend/assert_backend.h
rename to pw_assert_log/public_overrides/pw_assert_backend/check_backend.h
diff --git a/pw_assert_tokenized/BUILD.bazel b/pw_assert_tokenized/BUILD.bazel
index aa9f79f..fd29970 100644
--- a/pw_assert_tokenized/BUILD.bazel
+++ b/pw_assert_tokenized/BUILD.bazel
@@ -28,7 +28,7 @@
     ],
     hdrs = [
         "assert_public_overrides/pw_assert_backend/assert_lite_backend.h",
-        "check_public_overrides/pw_assert_backend/assert_backend.h",
+        "check_public_overrides/pw_assert_backend/check_backend.h",
         "public/pw_assert_tokenized/assert_tokenized.h",
         "public/pw_assert_tokenized/check_tokenized.h",
         "public/pw_assert_tokenized/handler.h",
diff --git a/pw_assert_tokenized/BUILD.gn b/pw_assert_tokenized/BUILD.gn
index 2b66d8b..9670b5a 100644
--- a/pw_assert_tokenized/BUILD.gn
+++ b/pw_assert_tokenized/BUILD.gn
@@ -72,7 +72,7 @@
     "$dir_pw_tokenizer",
   ]
   public = [
-    "check_public_overrides/pw_assert_backend/assert_backend.h",
+    "check_public_overrides/pw_assert_backend/check_backend.h",
     "public/pw_assert_tokenized/check_tokenized.h",
   ]
 }
diff --git a/pw_assert_tokenized/check_public_overrides/pw_assert_backend/assert_backend.h b/pw_assert_tokenized/check_public_overrides/pw_assert_backend/check_backend.h
similarity index 100%
rename from pw_assert_tokenized/check_public_overrides/pw_assert_backend/assert_backend.h
rename to pw_assert_tokenized/check_public_overrides/pw_assert_backend/check_backend.h
diff --git a/pw_assert_zephyr/public_overrides/pw_assert_backend/assert_backend.h b/pw_assert_zephyr/public_overrides/pw_assert_backend/check_backend.h
similarity index 100%
rename from pw_assert_zephyr/public_overrides/pw_assert_backend/assert_backend.h
rename to pw_assert_zephyr/public_overrides/pw_assert_backend/check_backend.h