fix(developer): verify context(n) offsets are valid in kmcmplib

developer/src/common/include/kmn_compiler_errors.h

@@ -272,6 +272,9 @@ namespace KmnCompilerMessages {
 
     HINT_IndexStoreLong =                               SevHint | 0x0B0,
 
+    ERROR_ContextExCannotReferenceIf =                  SevError | 0x0B1,
+    ERROR_ContextExCannotReferenceNul =                 SevError | 0x0B2,
+
     FATAL_BufferOverflow =                                SevFatal | 0x0C0
 //    FATAL_Break =                                         SevFatal | 0x0C1,      unused
   };

developer/src/kmc-kmn/src/compiler/kmn-compiler-messages.ts

@@ -737,7 +737,19 @@ export class KmnCompilerMessages {
   static HINT_IndexStoreLong                                  = SevHint | 0x0B0;
   static Hint_IndexStoreLong                                  = () => m(
     this.HINT_IndexStoreLong,
-    `The store referenced in index() is longer than the store referenced in any()`
+    `The store referenced in index() is longer than the store referenced in any()`,
+  );
+
+  static ERROR_ContextExCannotReferenceIf                     = SevError | 0x0B1;
+  static Error_ContextExCannotReferenceIf                     = () => m(
+    this.ERROR_ContextExCannotReferenceIf,
+    `The offset in context() points to a non-character if() statement in the context`,
+  );
+
+  static ERROR_ContextExCannotReferenceNul                    = SevError | 0x0B2;
+  static Error_ContextExCannotReferenceNul                     = () => m(
+    this.ERROR_ContextExCannotReferenceNul,
+    `The offset in context() points to a non-character nul statement in the context`,
   );
 
   static FATAL_BufferOverflow                                 = SevFatal | 0x0C0;

developer/src/kmc-kmn/test/fixtures/invalid-keyboards/error_contextex_cannot_reference_if.kmn

@@ -0,0 +1,11 @@
+store(&TARGETS) 'any'
+
+begin Unicode > use(main)
+
+store(cons) 'bcd'
+store(ifx) '1'
+
+group(main) using keys
+
+c ERROR_ContextExCannotReferenceIf:
+if(ifx = '1') any(cons) + 'd' > context(1)

developer/src/kmc-kmn/test/fixtures/invalid-keyboards/error_contextex_cannot_reference_nul.kmn

@@ -0,0 +1,10 @@
+store(&TARGETS) 'any'
+
+begin Unicode > use(main)
+
+store(cons) 'bcd'
+
+group(main) using keys
+
+c ERROR_ContextExCannotReferenceNul:
+nul any(cons) + 'a' > 'x' context(1)

developer/src/kmc-kmn/test/fixtures/invalid-keyboards/error_contextex_has_invalid_offset_if.kmn

@@ -0,0 +1,12 @@
+store(&TARGETS) 'any'
+
+begin Unicode > use(main)
+
+store(cons) 'bcd'
+store(ifx) '1'
+
+group(main) using keys
+
+c ERROR_ContextExHasInvalidOffset: `context(3)` should be `context(2)`
+if(ifx='1') any(cons) + 'a' > 'x' context(3) 'z'
+

developer/src/kmc-kmn/test/fixtures/invalid-keyboards/error_contextex_has_invalid_offset_long.kmn

@@ -0,0 +1,11 @@
+store(&TARGETS) 'any'
+
+begin Unicode > use(main)
+
+store(cons) 'bcd'
+
+group(main) using keys
+
+c ERROR_ContextExHasInvalidOffset: `context(2)` is longer than range
+any(cons) + 'a' > 'x' context(2) 'z'
+

developer/src/kmc-kmn/test/fixtures/invalid-keyboards/error_contextex_has_invalid_offset_nul.kmn

@@ -0,0 +1,12 @@
+store(&TARGETS) 'any'
+
+begin Unicode > use(main)
+
+store(cons) 'bcd'
+store(ifx) '1'
+
+group(main) using keys
+
+c ERROR_ContextExHasInvalidOffset: `context(3)` should be `context(2)`
+nul any(cons) + 'a' > 'x' context(3) 'z'
+

developer/src/kmc-kmn/test/fixtures/invalid-keyboards/error_contextex_has_invalid_offset_zero.kmn

@@ -0,0 +1,11 @@
+store(&TARGETS) 'any'
+
+begin Unicode > use(main)
+
+store(cons) 'bcd'
+
+group(main) using keys
+
+c ERROR_ContextExHasInvalidOffset: `context(0)` is lower than 1
+any(cons) + 'a' > 'x' context(0) 'z'
+

developer/src/kmc-kmn/test/messages.tests.ts

@@ -185,16 +185,35 @@ describe('KmnCompilerMessages', function () {
 
   it('should generate WARN_IndexStoreShort if a store referenced in index() is shorter than the corresponding any() store', async function() {
     await testForMessage(this, ['keyboards', 'warn_index_store_short.kmn'], KmnCompilerMessages.WARN_IndexStoreShort);
-    callbacks.clear();
     await testForMessage(this, ['keyboards', 'warn_index_store_short_key.kmn'], KmnCompilerMessages.WARN_IndexStoreShort);
   });
 
   // HINT_IndexStoreLong
 
   it('should generate HINT_IndexStoreLong if a store referenced in index() is longer than the corresponding any() store', async function() {
     await testForMessage(this, ['keyboards', 'hint_index_store_long.kmn'], KmnCompilerMessages.HINT_IndexStoreLong);
-    callbacks.clear();
     await testForMessage(this, ['keyboards', 'hint_index_store_long_key.kmn'], KmnCompilerMessages.HINT_IndexStoreLong);
   });
 
+  // ERROR_ContextExHasInvalidOffset
+
+  it('should generate ERROR_ContextExHasInvalidOffset if the offset is lower than 1 or greater than the context length', async function() {
+    await testForMessage(this, ['invalid-keyboards', 'error_contextex_has_invalid_offset_if.kmn'], KmnCompilerMessages.ERROR_ContextExHasInvalidOffset);
+    await testForMessage(this, ['invalid-keyboards', 'error_contextex_has_invalid_offset_long.kmn'], KmnCompilerMessages.ERROR_ContextExHasInvalidOffset);
+    await testForMessage(this, ['invalid-keyboards', 'error_contextex_has_invalid_offset_nul.kmn'], KmnCompilerMessages.ERROR_ContextExHasInvalidOffset);
+    await testForMessage(this, ['invalid-keyboards', 'error_contextex_has_invalid_offset_zero.kmn'], KmnCompilerMessages.ERROR_ContextExHasInvalidOffset);
+  });
+
+  // ERROR_ContextExCannotReferenceIf
+
+  it('should generate ERROR_ContextExCannotReferenceIf if the offset points to an if() statement', async function() {
+    await testForMessage(this, ['invalid-keyboards', 'error_contextex_cannot_reference_if.kmn'], KmnCompilerMessages.ERROR_ContextExCannotReferenceIf);
+  });
+
+  // ERROR_ContextExCannotReferenceNul
+
+  it('should generate ERROR_ContextExCannotReferenceNul if the offset points to a nul statement', async function() {
+    await testForMessage(this, ['invalid-keyboards', 'error_contextex_cannot_reference_nul.kmn'], KmnCompilerMessages.ERROR_ContextExCannotReferenceNul);
+  });
+
 });

developer/src/kmcmplib/src/Compiler.cpp

@@ -1458,13 +1458,23 @@ KMX_DWORD CheckStatementOffsets(PFILE_KEYBOARD fk, PFILE_GROUP gp, PKMX_WCHAR co
         }
       } else if (*(p + 1) == CODE_CONTEXTEX) {
         int contextOffset = *(p + 2);
-        if (contextOffset > xstrlen(context))
+        if (contextOffset > xstrlen(context)) {
           return KmnCompilerMessages::ERROR_ContextExHasInvalidOffset;
+        }
+
+        // contextOffset <= 0 is tested in parse stage
+
+        for (q = context, i = 1; *q && i < contextOffset; q = incxstr(q), i++);
+        if(*q == UC_SENTINEL && (*(q + 1) == CODE_IFOPT || *(q + 1) == CODE_IFSYSTEMSTORE)) {
+          return KmnCompilerMessages::ERROR_ContextExCannotReferenceIf;
+        }
+        if(*q == UC_SENTINEL && *(q + 1) == CODE_NUL) {
+          return KmnCompilerMessages::ERROR_ContextExCannotReferenceNul;
+        }
 
         // Due to a limitation in earlier versions of KeymanWeb, the minimum version
         // for context() referring to notany() is 14.0. See #917 for details.
         if (kmcmp::CompileTarget == CKF_KEYMANWEB) {
-          for (q = context, i = 1; *q && i < contextOffset; q = incxstr(q), i++);
           if (*q == UC_SENTINEL && *(q + 1) == CODE_NOTANY) {
             if(!VerifyKeyboardVersion(fk, VERSION_140)) {
               return KmnCompilerMessages::ERROR_140FeatureOnlyContextAndNotAnyWeb;
@@ -2267,7 +2277,9 @@ KMX_DWORD GetXStringImpl(PKMX_WCHAR tstr, PFILE_KEYBOARD fk, PKMX_WCHAR str, KMX
           }
           int n1b;
           n1b = atoiW(q);
-          if (n1b < 1 || n1b >= 0xF000) return KmnCompilerMessages::ERROR_InvalidToken;
+          if (n1b < 1 || n1b >= 0xF000) {
+            return KmnCompilerMessages::ERROR_ContextExHasInvalidOffset;
+          }
           tstr[mx++] = UC_SENTINEL;
           tstr[mx++] = CODE_CONTEXTEX;
           tstr[mx++] = n1b;

developer/src/kmcmplib/tests/gtest-compiler.tests.cpp

@@ -1281,10 +1281,10 @@ TEST_F(CompilerTest, GetXStringImpl_type_c_test) {
     const KMX_WCHAR tstr_context_offset_valid[] = { UC_SENTINEL, CODE_CONTEXTEX, 1, 0 };
     EXPECT_EQ(0, u16cmp(tstr_context_offset_valid, tstr));
 
-    // context, CERR_InvalidToke, offset < 1
+    // context, ERROR_ContextExHasInvalidOffset, offset < 1
     fileKeyboard.version = VERSION_60;
     u16cpy(str, u"context(0)");
-    EXPECT_EQ(KmnCompilerMessages::ERROR_InvalidToken, GetXStringImpl(tstr, &fileKeyboard, str, u"", output, 80, 0, &newp, FALSE));
+    EXPECT_EQ(KmnCompilerMessages::ERROR_ContextExHasInvalidOffset, GetXStringImpl(tstr, &fileKeyboard, str, u"", output, 80, 0, &newp, FALSE));
 
     // context, large offset < 0xF000, valid
     fileKeyboard.version = VERSION_60;
@@ -1293,10 +1293,10 @@ TEST_F(CompilerTest, GetXStringImpl_type_c_test) {
     const KMX_WCHAR tstr_context_large_offset_valid[] = { UC_SENTINEL, CODE_CONTEXTEX, 61439, 0 };
     EXPECT_EQ(0, u16cmp(tstr_context_large_offset_valid, tstr));
 
-    // context, KmnCompilerMessages::ERROR_InvalidToken, too large offset == 0xF000
+    // context, KmnCompilerMessages::ERROR_ContextExHasInvalidOffset, too large offset == 0xF000
     fileKeyboard.version = VERSION_60;
     u16cpy(str, u"context(61440)"); //0xF000
-    EXPECT_EQ(KmnCompilerMessages::ERROR_InvalidToken, GetXStringImpl(tstr, &fileKeyboard, str, u"", output, 80, 0, &newp, FALSE));
+    EXPECT_EQ(KmnCompilerMessages::ERROR_ContextExHasInvalidOffset, GetXStringImpl(tstr, &fileKeyboard, str, u"", output, 80, 0, &newp, FALSE));
 
     // context, KmnCompilerMessages::ERROR_60FeatureOnly_Contextn
     fileKeyboard.version = VERSION_50;