Some SDK headers not compatible with -Wsign-conversion (IDFGH-2901)

[hb-kaertech]

Environment

• IDF version: v4.2-dev-701-g0ae960f2fe
• Build System: idf.py
• Compiler version: (crosstool-NG esp-2019r2) 8.2.0
• Operating System: Linux

Problem Description

I would like to compile my own code with the -Wsign-conversion cflag. Unfortunately, some of ESP-IDF headers are not compatible with this option and generate some warnings.

components/esp_http_server/include/esp_http_server.h:

@@ -1039,7 +1039,7 @@ esp_err_t httpd_resp_send_chunk(httpd_req_t *r, const char *buf, ssize_t buf_len
  *  - ESP_ERR_HTTPD_INVALID_REQ : Invalid request
  */
 static inline esp_err_t httpd_resp_sendstr(httpd_req_t *r, const char *str) {
-    return httpd_resp_send(r, str, (str == NULL) ? 0 : strlen(str));
+    return httpd_resp_send(r, str, (str == NULL) ? 0 : HTTPD_RESP_USE_STRLEN);
 }
 
 /**
@@ -1060,7 +1060,7 @@ static inline esp_err_t httpd_resp_sendstr(httpd_req_t *r, const char *str) {
  *  - ESP_ERR_HTTPD_INVALID_REQ : Invalid request
  */
 static inline esp_err_t httpd_resp_sendstr_chunk(httpd_req_t *r, const char *str) {
-    return httpd_resp_send_chunk(r, str, (str == NULL) ? 0 : strlen(str));
+    return httpd_resp_send_chunk(r, str, (str == NULL) ? 0 : HTTPD_RESP_USE_STRLEN);
 }
 
 /* Some commonly used status codes */

components/freertos/include/freertos/portable.h:
(maybe the right fix is changing the return type of cpu_hal_get_core_id ? Internally, cpu_hal_get_core_id uses an uint32_t.)

@@ -202,7 +202,7 @@ BaseType_t xPortInterruptedFromISRContext(void);
 
 /* Multi-core: get current core ID */
 static inline uint32_t IRAM_ATTR xPortGetCoreID(void) {
-    return cpu_hal_get_core_id();
+    return (uint32_t) cpu_hal_get_core_id();
 }
 
 /* Get tick rate per second */

components/xtensa/include/xtensa/xtruntime.h:

@@ -158,12 +158,12 @@ extern unsigned int       _xtos_ints_on( unsigned int mask );
 /* Newer functions to enable/disable the specified interrupt.  */
 static inline void _xtos_interrupt_enable(unsigned int intnum)
 {
-    _xtos_ints_on(1 << intnum);
+    _xtos_ints_on(1U << intnum);
 }
 
 static inline void _xtos_interrupt_disable(unsigned int intnum)
 {
-    _xtos_ints_off(1 << intnum);
+    _xtos_ints_off(1U << intnum);
 }
 
 extern unsigned                _xtos_set_intlevel( int intlevel );

Could you fix these? Thank you!

Code to reproduce this issue

1. Patch on the SDK examples to include the headers mentioned above.
2. Add this after idf_component_register(): target_compile_options(${COMPONENT_LIB} PRIVATE "-Wsign-conversion")