fix: pad source read buffers in all parse passes (tree-sitter lookahead)

Same fix as read_file in pass_definitions: the calls/usages/semantic/k8s/lsp_cross passes each read a source file into a malloc'd buffer and re-parse it, so they hit the same tree-sitter lexer over-read past EOF under ASan. Over-allocate by 16 and zero the tail in every reader.

src/pipeline/pass_calls.c

@@ -46,7 +46,9 @@ static char *read_file(const char *path, int *out_len) {
         return NULL;
     }
 
-    char *buf = malloc(size + SKIP_ONE);
+    /* +pad: tree-sitter lexer lookahead reads past EOF; keep it in-bounds */
+    enum { CBM_TS_LOOKAHEAD_PAD = 16 };
+    char *buf = malloc((size_t)size + CBM_TS_LOOKAHEAD_PAD);
     if (!buf) {
         (void)fclose(f);
         return NULL;
@@ -58,7 +60,7 @@ static char *read_file(const char *path, int *out_len) {
     if (nread > (size_t)size) {
         nread = (size_t)size;
     }
-    buf[nread] = '\0';
+    memset(buf + nread, 0, CBM_TS_LOOKAHEAD_PAD);
     *out_len = (int)nread;
     return buf;
 }

src/pipeline/pass_k8s.c

@@ -44,7 +44,9 @@ static char *k8s_read_file(const char *path, int *out_len) {
         return NULL;
     }
 
-    char *buf = malloc(size + SKIP_ONE);
+    /* +pad: tree-sitter lexer lookahead reads past EOF; keep it in-bounds */
+    enum { CBM_TS_LOOKAHEAD_PAD = 16 };
+    char *buf = malloc((size_t)size + CBM_TS_LOOKAHEAD_PAD);
     if (!buf) {
         (void)fclose(f);
         return NULL;
@@ -55,7 +57,7 @@ static char *k8s_read_file(const char *path, int *out_len) {
     if (nread > (size_t)size) {
         nread = (size_t)size;
     }
-    buf[nread] = '\0';
+    memset(buf + nread, 0, CBM_TS_LOOKAHEAD_PAD);
     *out_len = (int)nread;
     return buf;
 }

src/pipeline/pass_lsp_cross.c

@@ -64,7 +64,9 @@ static char *pxc_read_file(const char *path, int *out_len) {
         (void)fclose(f);
         return NULL;
     }
-    char *buf = (char *)malloc((size_t)size + 1);
+    /* +pad: tree-sitter lexer lookahead reads past EOF; keep it in-bounds */
+    enum { CBM_TS_LOOKAHEAD_PAD = 16 };
+    char *buf = (char *)malloc((size_t)size + CBM_TS_LOOKAHEAD_PAD);
     if (!buf) {
         (void)fclose(f);
         return NULL;
@@ -73,7 +75,7 @@ static char *pxc_read_file(const char *path, int *out_len) {
     (void)fclose(f);
     if (nread > (size_t)size)
         nread = (size_t)size;
-    buf[nread] = '\0';
+    memset(buf + nread, 0, CBM_TS_LOOKAHEAD_PAD);
     *out_len = (int)nread;
     return buf;
 }

src/pipeline/pass_semantic.c

@@ -36,7 +36,9 @@ static char *read_file(const char *path, int *out_len) {
         (void)fclose(f);
         return NULL;
     }
-    char *buf = malloc(size + SKIP_ONE);
+    /* +pad: tree-sitter lexer lookahead reads past EOF; keep it in-bounds */
+    enum { CBM_TS_LOOKAHEAD_PAD = 16 };
+    char *buf = malloc((size_t)size + CBM_TS_LOOKAHEAD_PAD);
     if (!buf) {
         (void)fclose(f);
         return NULL;
@@ -46,7 +48,7 @@ static char *read_file(const char *path, int *out_len) {
     if (nread > (size_t)size) {
         nread = (size_t)size;
     }
-    buf[nread] = '\0';
+    memset(buf + nread, 0, CBM_TS_LOOKAHEAD_PAD);
     *out_len = (int)nread;
     return buf;
 }

src/pipeline/pass_usages.c

@@ -36,7 +36,9 @@ static char *read_file(const char *path, int *out_len) {
         (void)fclose(f);
         return NULL;
     }
-    char *buf = malloc(size + SKIP_ONE);
+    /* +pad: tree-sitter lexer lookahead reads past EOF; keep it in-bounds */
+    enum { CBM_TS_LOOKAHEAD_PAD = 16 };
+    char *buf = malloc((size_t)size + CBM_TS_LOOKAHEAD_PAD);
     if (!buf) {
         (void)fclose(f);
         return NULL;
@@ -46,7 +48,7 @@ static char *read_file(const char *path, int *out_len) {
     if (nread > (size_t)size) {
         nread = (size_t)size;
     }
-    buf[nread] = '\0';
+    memset(buf + nread, 0, CBM_TS_LOOKAHEAD_PAD);
     *out_len = (int)nread;
     return buf;
 }