Rework [76c8435a] to eliminate automatic JS-to-WASM function conversions of sqlite3_set_auxdata() destructors because it can leads to leaks on every call of a UDF. This feature never worked before [76c8435a] but fixing it was ill-conceived because of the memory leakage it introduces. WASM function pointers can still be used as destructors in this context.

FossilOrigin-Name: 3fb993af0caf041da934cea29c039b27c468be0b75bce1537a6425767cf9bf8d

ext/wasm/api/sqlite3-api-glue.c-pp.js

@@ -229,14 +229,15 @@ globalThis.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
       '*'
     ]],
     /**
-       2025-02-03: We do not have a way to automatically clean up
+       We do not have a way to automatically clean up destructors
-       destructors which are automatically converted from JS functions
+       which are automatically converted from JS functions via the
-       via the final argument to sqlite3_set_auxdata(). Because of
+       final argument to sqlite3_set_auxdata(). Because of that,
-       that, it is strongly recommended that clients use
+       automatic function conversion is not supported for this
-       wasm.installFunction() to create such callbacks, then pass that
+       function.  Clients should use wasm.installFunction() to create
-       pointer to sqlite3_set_auxdata(). Relying on automated
+       such callbacks, then pass that pointer to
-       conversions here will lead to leaks of JS/WASM proxy functions
+       sqlite3_set_auxdata(). Relying on automated conversions here
-       because sqlite3_set_auxdata() is frequently called in UDFs.
+       would lead to leaks of JS/WASM proxy functions because
+       sqlite3_set_auxdata() is frequently called in UDFs.
 
        The sqlite3.oo1.DB class's onclose handlers can be used for this
        purpose. For example:
@@ -252,14 +253,24 @@ globalThis.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
 
        Then pass pAuxDtor as the final argument to appropriate
        sqlite3_set_auxdata() calls.
+
+       Note that versions prior to 3.49.0 ostensibly had automatic
+       function conversion here but a typo prevented it from
+       working.  Rather than fix it, it was removed because testing the
+       fix brought the huge potential for memory leaks to the
+       forefront.
     */
     ["sqlite3_set_auxdata", undefined, [
       "sqlite3_context*", "int", "*",
-      new wasm.xWrap.FuncPtrAdapter({
+      true
-        name: 'xDestroyAuxData',
+        ? "*"
-        signature: 'v(p)',
+        : new wasm.xWrap.FuncPtrAdapter({
-        contextKey: (argv, argIndex)=>argv[0/* sqlite3_context* */]
+          /* If we can find a way to automate their cleanup, JS functions can
-      })
+             be auto-converted with this. */
+          name: 'xDestroyAuxData',
+          signature: 'v(p)',
+          contextKey: (argv, argIndex)=>argv[0/* sqlite3_context* */]
+        })
     ]],
     ["sqlite3_shutdown", undefined],
     ["sqlite3_sourceid", "string"],

ext/wasm/tester1.c-pp.js

@@ -3469,9 +3469,9 @@ globalThis.sqlite3InitModule = sqlite3InitModule;
                    We do not currently an automated way to clean up
                    auxdata finalizer functions (the 4th argument to
                    sqlite3_set_auxdata()) which get automatically
-                   converted from JS to WASM. Because of that, relying
+                   converted from JS to WASM. Because of that, enabling
-                   on automated conversions for those is not
+                   automated conversions here would lead to leaks more
-                   recommended. Instead, follow the pattern show in
+                   often than not. Instead, follow the pattern show in
                    this function: use wasm.installFunction() to create
                    the function, then pass the resulting function
                    pointer this function, and cleanup (at some point)

manifest

@@ -1,5 +1,5 @@
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+C Rework\s[76c8435a]\sto\seliminate\sautomatic\sJS-to-WASM\sfunction\sconversions\sof\ssqlite3_set_auxdata()\sdestructors\sbecause\sit\scan\sleads\sto\sleaks\son\severy\scall\sof\sa\sUDF.\sThis\sfeature\snever\sworked\sbefore\s[76c8435a]\sbut\sfixing\sit\swas\sill-conceived\sbecause\sof\sthe\smemory\sleakage\sit\sintroduces.\sWASM\sfunction\spointers\scan\sstill\sbe\sused\sas\sdestructors\sin\sthis\scontext.
-D 2025-02-03T14:55:56.185
+D 2025-02-03T17:34:12.962
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md e108e1e69ae8e8a59e93c455654b8ac9356a11720d3345df2a4743e9590fb20d
@@ -638,7 +638,7 @@ F ext/wasm/api/post-js-footer.js 365405929f41ca0e6d389ed8a8da3f3c93e11d3ef43a90a
 F ext/wasm/api/post-js-header.js 54b2b4294501b3866245cc94315a16f5424c0e87729d0fb610fba151593c6d26
 F ext/wasm/api/pre-js.c-pp.js a614a2c82b12c4d96d8e3ba77330329efc53c4d56a8a7e60ade900f341866cfb
 F ext/wasm/api/sqlite3-api-cleanup.js 3ac1786e461ada63033143be8c3b00b26b939540661f3e839515bb92f2e35359
-F ext/wasm/api/sqlite3-api-glue.c-pp.js 6e2f2eaf681e342fcb047fcdd01d6e3c1b466fb9b45c1acc38676164a8b60f45
+F ext/wasm/api/sqlite3-api-glue.c-pp.js 5c0209e6a28164b4c2c1a34b0bb4aee3b7b1a264988d7e71fac08b8ede5b7ae3
 F ext/wasm/api/sqlite3-api-oo1.c-pp.js f3a8e2004c6625d17946c11f2fb32008be78bc5207bf746fc77d59848813225f
 F ext/wasm/api/sqlite3-api-prologue.js 5ff913355b3144f1c9719d0406667fa6e13eb813c71ed7ce29440e2e65363e82
 F ext/wasm/api/sqlite3-api-worker1.c-pp.js 5cc22a3c0d52828cb32aad8691488719f47d27567e63e8bc8b832d74371c352d
@@ -696,7 +696,7 @@ F ext/wasm/test-opfs-vfs.html 1f2d672f3f3fce810dfd48a8d56914aba22e45c6834e262555
 F ext/wasm/test-opfs-vfs.js 1618670e466f424aa289859fe0ec8ded223e42e9e69b5c851f809baaaca1a00c
 F ext/wasm/tester1-worker.html ebc4b820a128963afce328ecf63ab200bd923309eb939f4110510ab449e9814c
 F ext/wasm/tester1.c-pp.html 1c1bc78b858af2019e663b1a31e76657b73dc24bede28ca92fbe917c3a972af2
-F ext/wasm/tester1.c-pp.js fb8d0761daaa69bd40c8253cc2d6c8c37ada97e1751b7f07af7369842ba2aeae
+F ext/wasm/tester1.c-pp.js 45000532cf83f23a52b31581c1db44bfb82e383b1b68703ae4d3d838de3a833e
 F ext/wasm/tests/opfs/concurrency/index.html 657578a6e9ce1e9b8be951549ed93a6a471f4520a99e5b545928668f4285fb5e
 F ext/wasm/tests/opfs/concurrency/test.js d08889a5bb6e61937d0b8cbb78c9efbefbf65ad09f510589c779b7cc6a803a88
 F ext/wasm/tests/opfs/concurrency/worker.js 0a8c1a3e6ebb38aabbee24f122693f1fb29d599948915c76906681bb7da1d3d2
@@ -2209,8 +2209,8 @@ F tool/version-info.c 3b36468a90faf1bbd59c65fd0eb66522d9f941eedd364fabccd7227350
 F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee87c1b31a7
 F tool/warnings.sh 49a486c5069de041aedcbde4de178293e0463ae9918ecad7539eedf0ec77a139
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 91ef45fc2902e46813366ec6b8317209f39f10e4a23c3808e33aceedab9da6c7
+P d693c2dddbd10a2e0b77893b04b11502e30b768f1b06814105f7f35172845fb9
-R f2c90877762eddda2efda339cfb2ee34
+R bdcc5096cc30e3d83fdf5d66602909e7
 U stephan
-Z 6cfffa02c18a4e52a298c977368cc8d7
+Z fd720e9f1383b7c5da4643ab36634ed7
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-d693c2dddbd10a2e0b77893b04b11502e30b768f1b06814105f7f35172845fb9
+3fb993af0caf041da934cea29c039b27c468be0b75bce1537a6425767cf9bf8d