Stop retaining a second SourceFile per file in the VFS environment#3616
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Gxrvish wants to merge 1 commit into
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Stop retaining a second SourceFile per file in the VFS environment#3616Gxrvish wants to merge 1 commit into
Gxrvish wants to merge 1 commit into
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createVirtualTypeScriptEnvironment's createFile and updateFile parsed a SourceFile and passed it to the virtual compiler host, which stored it in its sourceFiles map. The language service never reads that map: it reads text through getScriptSnapshot and parses and caches its own SourceFiles. Every file written through the environment was therefore held as two full ASTs for the lifetime of the environment, and the parse which produced the second one was discarded. The environment now writes contents through a text-only path, added as writeFileText on createVirtualCompilerHost and updateFileText on createVirtualLanguageServiceHost. writeFileText drops any cached AST for the file so a standalone compiler host cannot return stale contents. The existing updateFile(sourceFile) entry points are unchanged. In a 40 file benchmark this cut retained heap from 318MB to 209MB and removed 80 redundant parses.
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createVirtualTypeScriptEnvironment's createFile and updateFile parsed a SourceFile and passed it to the virtual compiler host, which stored it in its sourceFiles map. The language service never reads that map: it reads text through getScriptSnapshot and parses and caches its own SourceFiles. Every file written through the environment was therefore held as two full ASTs for the lifetime of the environment, and the parse which produced the second one was discarded.
The environment now writes contents through a text-only path, added as writeFileText on createVirtualCompilerHost and updateFileText on createVirtualLanguageServiceHost. writeFileText drops any cached AST for the file so a standalone compiler host cannot return stale contents. The existing updateFile(sourceFile) entry points are unchanged.
In a 40 file benchmark this cut retained heap from 318MB to 209MB and removed 80 redundant parses.
Fixes: #3614