tidy-up: drop redundant == NULL syntax

Where missed by checksrc.

Closes #21935

lib/cfilters.h

@@ -657,7 +657,7 @@ struct cf_call_data {
 #define CF_DATA_SAVE(save, cf, data) \
   do { \
     (save) = CF_CTX_CALL_DATA(cf); \
-    DEBUGASSERT((save).data == NULL || (save).depth > 0); \
+    DEBUGASSERT(!(save).data || (save).depth > 0); \
     CF_CTX_CALL_DATA(cf).depth++;  \
     CF_CTX_CALL_DATA(cf).data = (struct Curl_easy *)CURL_UNCONST(data); \
   } while(0)
@@ -665,7 +665,7 @@ struct cf_call_data {
 #define CF_DATA_RESTORE(cf, save) \
   do { \
     DEBUGASSERT(CF_CTX_CALL_DATA(cf).depth == (save).depth + 1); \
-    DEBUGASSERT((save).data == NULL || (save).depth > 0); \
+    DEBUGASSERT(!(save).data || (save).depth > 0); \
     CF_CTX_CALL_DATA(cf) = (save); \
   } while(0)
 

lib/easy.c

@@ -942,7 +942,7 @@ static void dupeasy_meta_freeentry(void *p)
   /* Always FALSE. Cannot use a 0 assert here since compilers
    * are not in agreement if they then want a NORETURN attribute or
    * not. *sigh* */
-  DEBUGASSERT(p == NULL);
+  DEBUGASSERT(!p);
 }
 
 /*

lib/ftplistparser.c

@@ -196,7 +196,7 @@ void Curl_wildcard_dtor(struct WildcardData **wcp)
     wc->dtor = ZERO_NULL;
     wc->ftpwc = NULL;
   }
-  DEBUGASSERT(wc->ftpwc == NULL);
+  DEBUGASSERT(!wc->ftpwc);
 
   Curl_llist_destroy(&wc->filelist, NULL);
   curlx_safefree(wc->path);

lib/multi.c

@@ -220,7 +220,7 @@ static void ph_freeentry(void *p)
   /* Always FALSE. Cannot use a 0 assert here since compilers
    * are not in agreement if they then want a NORETURN attribute or
    * not. *sigh* */
-  DEBUGASSERT(p == NULL);
+  DEBUGASSERT(!p);
 }
 
 /*

lib/pingpong.c

@@ -152,7 +152,7 @@ CURLcode Curl_pp_vsendf(struct Curl_easy *data,
 
   DEBUGASSERT(pp->sendleft == 0);
   DEBUGASSERT(pp->sendsize == 0);
-  DEBUGASSERT(pp->sendthis == NULL);
+  DEBUGASSERT(!pp->sendthis);
 
   if(!conn)
     /* cannot send without a connection! */

lib/url.c

@@ -442,7 +442,7 @@ static void easy_meta_freeentry(void *p)
   /* Always FALSE. Cannot use a 0 assert here since compilers
    * are not in agreement if they then want a NORETURN attribute or
    * not. *sigh* */
-  DEBUGASSERT(p == NULL);
+  DEBUGASSERT(!p);
 }
 
 /**
@@ -2591,7 +2591,7 @@ static void conn_meta_freeentry(void *p)
   /* Always FALSE. Cannot use a 0 assert here since compilers
    * are not in agreement if they then want a NORETURN attribute or
    * not. *sigh* */
-  DEBUGASSERT(p == NULL);
+  DEBUGASSERT(!p);
 }
 
 static CURLcode url_create_needle(struct Curl_easy *data,

lib/vssh/libssh.c

@@ -1888,8 +1888,8 @@ static void sshc_cleanup(struct ssh_conn *sshc)
     }
 
     /* worst-case scenario cleanup */
-    DEBUGASSERT(sshc->ssh_session == NULL);
-    DEBUGASSERT(sshc->scp_session == NULL);
+    DEBUGASSERT(!sshc->ssh_session);
+    DEBUGASSERT(!sshc->scp_session);
 
     if(sshc->readdir_tmp) {
       ssh_string_free_char(sshc->readdir_tmp);

lib/vssh/libssh2.c

@@ -152,8 +152,7 @@ static void kbd_callback(const char *name, int name_len,
     /* this function must allocate memory that can be freed by libssh2, which
        uses the LIBSSH2_FREE_FUNC callback */
     responses[0].text = Curl_cstrdup(passwd);
-    responses[0].length =
-      responses[0].text == NULL ? 0 : curlx_uztoui(strlen(passwd));
+    responses[0].length = responses[0].text ? curlx_uztoui(strlen(passwd)) : 0;
   }
   (void)prompts;
 } /* kbd_callback */
@@ -2607,12 +2606,12 @@ static CURLcode sshc_cleanup(struct ssh_conn *sshc, struct Curl_easy *data,
   }
 
   /* worst-case scenario cleanup */
-  DEBUGASSERT(sshc->ssh_session == NULL);
-  DEBUGASSERT(sshc->ssh_channel == NULL);
-  DEBUGASSERT(sshc->sftp_session == NULL);
-  DEBUGASSERT(sshc->sftp_handle == NULL);
-  DEBUGASSERT(sshc->kh == NULL);
-  DEBUGASSERT(sshc->ssh_agent == NULL);
+  DEBUGASSERT(!sshc->ssh_session);
+  DEBUGASSERT(!sshc->ssh_channel);
+  DEBUGASSERT(!sshc->sftp_session);
+  DEBUGASSERT(!sshc->sftp_handle);
+  DEBUGASSERT(!sshc->kh);
+  DEBUGASSERT(!sshc->ssh_agent);
 
   curlx_safefree(sshc->rsa_pub);
   curlx_safefree(sshc->rsa);

lib/vtls/rustls.c

@@ -1100,7 +1100,7 @@ static CURLcode cr_init_backend(struct Curl_cfilter *cf,
     return CURLE_SSL_CONNECT_ERROR;
   }
 
-  DEBUGASSERT(rconn == NULL);
+  DEBUGASSERT(!rconn);
   rr = rustls_client_connection_new(backend->config,
                                     connssl->peer.dest->hostname,
                                     &rconn);